tu dien thien van hoc

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CLB THIN VN BCH KHOA

T I NTHIN VN H C

N ng - 2008


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AAbsolute Magnitudea scale for measuring the actual brightness of a celestial object without accounting for the

distance of the object. Absolute magnitude measures how bright an object would appear if itwere exactly 10 parsecs (about 33 light years) away from Earth. On this scale, the Sun has anabsolute magnitude of +4.8 while it has an apparent magnitude of -26.7 because it is so close.

sng tuy t iM t th c o tnh sng hi n t i c a m t thin th m khng k n xa c a n.

sng tuy t i th hi n sng c a m t thin th s nh th no n u n cch xa Tri tng b ng 10 parsec (kho ng 33 nm nh sng). V i n v ny, M t Tr i c sng tuy t i b ng +4,8 trong khi n c sng bi u ki n l -26,7 v n qu g n.

Absolute Zerothe temperature at which the motion of all atoms and molecules stops and no heat is given off.Absolute zero is reached at 0 degrees Kelvin or -273.16 degrees Celsius.

khng tuy t iNhi t m t i chuy n ng c a m i nguyn t v phn t u ng ng h n v

khng pht ra nhi t l ng. khng tuy t i b ng 0 Kelvin hay -273,16 Celsius.

Accretion

process of particles sticking together to form larger bodies; for example, solar nebular dustaccreted to form chondrules, and planetesimals accreted to form planets.

S tng tr ngQu trnh cc m nh v t ch t nh k t n i v i nhau thnh nh ng kh i v t ch t l n h n; v

d , b i c a tinh vn m t tr i lin k t v i nhau tr thnh m nh thin th ch d ng c u v nh ngti n hnh tinh lin k t tr thnh hnh tinh.

Achondrite

a stony meteorite representing differentiated planetary material.

L m t lo i thin th ch c thnh ph n khc v i thnh ph n c a hnh tinh.


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Albedo Featurea dark or light marking on the surface of an object that may or may not be a geological ortopographical feature. Albedo is the measure of the reflectivity of a planet, measured on ascale from zero to one. An albedo of zero describes a planet that absorbs all the light itreceives. A planet with an albedo of one reflects all the light that shines on it.

Su t phn chi u c tr ngM t v t sng ho c t i trn b m t m t thin th m c th ho c khng thu c a ch t

ho c a hnh. Su t phn chi u (albedo) l th c o ph n chi u c a m t hnh tinh, tnhtrong thang t khng t i m t. Khng albedo th hi n hnh tinh h p th t t c nh sngn nh n c. M t hnh tinh c m t albedo ph n x hon ton nh sng t i n.

Alpha Centaurithe closest bright star to our solar system.

Nhn M Alpha ( qui nhn m)Ngi sao sng g n h m t tr i nh t

Altitudeangle in degrees above the horizon.

cao so v i m t bi nGc tnh theo so v i ng chn tr i.

Angstromabbreviated . A unit of length equal to 10 -8 cm (one-hundredth of a millionth of a centimeter).An Angstrom is on the order of the size of an atom.

AngxtrngK hi u . M t n v o chi u di b ng 10-8 cm (m t ph n m t trm nghn centimet).

Angstrom dng bi u di n kch th c c a nguyn t .

Antimattermatter consisting of particles with charges opposite that of ordinary matter. In antimatter,protons have a negative charge while electrons have a positive charge.

Ph n v t ch tH t v t ch t c i n tch ng c l i so v i h t g c. Trong ph n v t ch t, proton c i n

tch m, cn electron c i n tch d ng.


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Antipodal pointthe point that is directly on the opposite side of the planet; e.g., the Earth's north pole isantipodal to its south pole.

i m i l pV tr n m i di n m t bn kia c a hnh tinh; v d , c c b c c a Tri t l i m i

l p c a c c nam.

Apastronthe point of greatest separation of two stars, such as in a binary star system.

i m hai ngi sao cch xa nhau nh t, nh trong m t h sao nh phn.

Aperturethe size of the opening through which light passes in an optical instrument such as a camera

or telescope. A higher number represents a smaller opening while a lower number representsa larger opening.

mKch th c c a c a m nh sng c th i qua cc d ng c quang h c nh my

nh hay knh vi n v ng. Con s l n bi u th cho m nh v con s nh bi u th cho ml n.Aphelionthe point in its orbit where a planet is farthest from the Sun.

i m vi n nh t

V tr trn qu o m m t hnh tinh xa M t Tr i nh t.

Apoapsisthe point in orbit farthest from the planet.

Vi n i m qu oV tr trn qu o xa m t hnh tinh nh t.

Apogeethe point in orbit farthest from the Earth.

i m vi n ai m trn qu o xa Tri t nh t.


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Apparent Magnitudethe apparent brightness of an object in the sky as it appears to an observer on Earth. Brightobjects have a low apparent magnitude while dim objects will have a higher apparentmagnitude.

sng bi u ki n sng bi u ki n c a m t thin th trn b u tr i c o khi quan st trn Tri t.

Nh ng thin th sng c sng bi u ki n th p v nh ng thin th t i c sng bi u ki ncao.

Arc Secondabbreviated arcsec. A unit of angular measure in which there are 60 arc seconds in 1 arcminute and therefore 3600 arc seconds in 1 arc degree. There are 206,265 arcseconds perradian. One arc second is equal to about 725 km on the Sun.

GiyVi t t t arcsec. M t n v c a gc trong 60 giy b ng 1 pht v v v y 3600 giyb ng 1 . 206.265 giy b ng 1 radian. M t giy b ng kho ng 725 km trn M t Tr i.

Arc Degreea unit of angular measure in which there are 360 arc degrees in a full circle.

M t n v o gc trong c 360 trong m t vng trn.

Arc Minuteone 1/60 of a degree.

PhtB ng 1/60 .

Asteroida small planetary body in orbit around the Sun, larger than a meteoroid but smaller than aplanet. Most asteroids can be found in a belt between the orbits of Mars and Jupiter. Theorbits of some asteroids take them close to the Sun, which also takes them across the pathsof the planets.

Ti u hnh tinhM t thin th nh c qu o xoay quanh M t Tr i, l n h n thin th ch nh ng nh h n

hnh tinh. H u h t ti u hnh tinh c th c tm th y trong vnh ai gi a qu o c a SaoH a v Sao M c. Nh ng qu o c a vi ti u hnh tinh lm chng n g n M t tr i, c ng lmchng ngang qua qu o c a nh ng hnh tinh (t o thnh m a sao bng )


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Astrochemistrythe branch of science that explores the chemical interactions between dust and gasinterspersed between the stars.

Ha h c thin thM t ngnh khoa h c nghin c u s t ng tc ha h c gi a b i v kh n m r i rc gi a

cc ngi sao.

Astronomical unit (AU)the average distance from the Earth to the Sun; 1 AU is 149,597,870 kilometers (92,96 0,116miles).

n v thin vn(AU)Kho ng cch trung bnh gi a Tri t v M t Tr i; 1 AU b ng 149.597.870 km.

Atmosphere

one atmosphere is 14.7 pounds per square inch (105 Newtons per square meter); the averageatmospheric pressure at sea level on Earth. Atmosphere is also a layer of gases surroundinga planet, moon, or star. The Earth's atmosphere is 120 miles thick and is composed mainly ofnitrogen, oxygen, carbon dioxide, and a few other trace gases.

AtmosphereM t atmosphere b ng 105 Newton trn mt vung; p su t trung bnh c a kh quy n

m c n c bi n. Kh quy n l l p khng kh bao b c xung quanh m t hnh tinh, m t trng,hay sao. Kh quy n c a Tri t dy 192 km v c thnh ph n ch y u l nit , oxy, cacbonic,v m t s ch t kh khc.

Auroraa glow in a planet's ionosphere caused by the interaction between the planet's magnetic fieldand charged particles from the Sun.

C c quangS pht sng trong t ng i n ly c a m t hnh tinh do s t ng tc gi a t tr ng c a

hnh tinh v i cc h t i n tch t M t Tr i.

Aurora Borealisthe Northern Lights caused by the interaction between the solar wind, the Earth's magneticfield and the upper atmosphere; a similar effect happens in the southern hemisphere where itis known as the aurora australis.

C c quang BorealisCn g i l B c c c quang gy ra b i s t ng tc gi a gi m t tr i, t tr ng c a Tri

t v t ng trn c a b u kh quy n; m t hi n t ng t ng t c ng x y ra bn c u nam ctn l c c quang australis.


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Azimuththe angular distance of an object around or parallel to the horizon from a predefined zeropoint.

Gc ph ng vGc kho ng cch c a m t thin th quanh ho c song song v i ng chn tr i t

i m khng ban u.

BBara unit of measure of atmospheric pressure. One bar is equal t o 0.987 atmospheres, 1.02kg/cm2, 100 kilopascal, and 14.5 lbs/square inch.

Bar

M t n v o l ng p su t kh quy n. M t bar b ng 0,987 atmosphere, 1,02 kg/cm 2,100 kilpascal, v 14,5 lbs/inch2.

Barycenterthe center of mass of a system of bodies; e.g., the center of mass of the solar system.

Tm kh i chungTrung tm c a kh i l ng c a m t h cc v t; v d , trung tm kh i l ng c a h m t

tr i.

Basalta general term for dark -colored, igneous rocks composed of minerals that are relatively rich iniron and magnesium.

BazanM t thu t ng ph bi n ch th m mu, g m cc khong ch t t ng i giu s t

v magie.

Big Bangthe theory that suggests that the universe was formed from a single point in space during acataclysmic explosion about 18 billion years ago. The force of the ex plosion accounts for thecurrent expansion of the universe.

V n l nGi thuy t ni r ng v tr c hnh thnh t m t i m duy nh t trong khng gian

trong m t v n l n kho ng 18 t nm tr c. L c c a v n gi i thch cho hi n tr ng gin nc a v tr hi n t i.


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Binary Starsa system of two stars that revolve around a common center of gravity.

Sao nh phnM t h g m 2 ngi sao quay trn quanh m t tm kh i chung.

Black Holethe collapsed core of a mass ive star. Stars that are very massive will collapse under their owngravity when their fuel is exhausted. The collapse continues until all matter is crushed out ofexistence into what is known as a singularity. The gravitational pull is so strong that not evenlight can escape.

L enNhn b s p c a m t ngi sao l n. Cc ngi sao r t n ng s s p vo l c h p d n

c a chnh chng khi nhin liu c a chng c n ki t. S s p ti p di n cho t i khi t t c v tch t nn thnh m t i m c coi l i m k d. L c d p d n m nh n n i ngay c nh

sng c ng khng thot c.

Blueshifta shift in the lines of an object's spectrum toward the blue end. Blueshift indicates that anobject ismoving toward the observer. The larger the blueshift, the faster the object is moving.

Dch chuy n xanhM t s dch chuy n trn ng quang ph c a m t thin th v pha mu xanh. Dch

chuy n xanh bi u th thin th ang dch chuy n v pha ng i quan st. Dch chuy n v

pha tm cn l n th thin th di chuy n cng nhanh.

Bolidean exploding meteorite.

Sao bngM t v n th ch ang chy.


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CCalderaa large, basin-shaped volcanic depression that is more or less circular in form. Mo st volcaniccalderas are produced by collapse of the roof of a magma chamber due to removal of magmaby voluminous eruptions or subterranean withdrawal of the magma, although some calderasmay be formed by explosive removal of the upper part of a volcano.

Mi ng ni l aM t v t lm l n d ng lng ch o t nhi u d ng hnh trn. H u h t mi ng ni l a c

t o ra b i s s p c a l p n n c a magma do s dch chuy n c a magma b ng cch phuntro ho c s rt i c a magma, d v y m t s mi ng ni l a c t o ra b ng s bng ntrn nh ni l a.

Carbonaceous chondritea type of primitive chondrite with evidence of nebular processes.

M t lo i (xem chondrite) c ch a b ng ch ng v qu trnh hnh thnh c a cc tinhvn.

Celestial equatorthe intersection of the earth's equatorial plane with the celestial sphere.

Xch o b u tr iHnh chi u c a ng xch o c a Tri t ln thin c u.

Celestial polethe north and south celestial poles are points on the celestial sphere whe re earths axis ofrotation intersects the celestial sphere.

C c b u tr iC c b c v nam b u tr i l nh ng i m trn thin c u n i tr c c a Tri t giao v i

thin c u.

Celestial spherean imaginary sphere centered on the earth on which all of the sta rs are imagined to beprojected.

Thin c uM t khng gian t ng t ng bao quanh Tri t cc ngi sao c t ng t ng n m

trn .


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Cepheida pulsating variable star. This type of star undergoes a rhythmic pulsation as indicated by itsregular pattern of changing brightness as a function of time. The period of pulsation has beendemonstrated to be directly related to a Cepheid's intrinsic brightness making observations ofthese stars one of the most powerful tools for determining distance known to mo dern dayastronomy.

Sao tu n hon (dch t m)M t ngi sao thay i th ng xuyn. Lo i sao ny xu t hi n nhp nhng nh nhp tim

c bi u hi n s thay i sng tu n hon c a n h t nh m t ng h th i gian. Chuk c a m t nhp c ch ng minh c lin quan tr c ti p t i b n ch t sng c a Sao tu n honv vi c quan st nh ng ngi sao ny l m t trong nh ng cng c h u ch nh t o t m hi ubi t c a thin vn h c hi n i.

CGScentimeter-Gram-Second (abbreviated cm-gm-sec or cm-g-s). The system of measurementthat uses these units for distance, mass, and time.

Centimet-gam-giyVi t t t cm-gm-sec hay cm-g-s. L h th ng o l ng dng nh ng n v ny o

kho ng cch, kh i l ng, v th i gian.

Chondritea meteorite containing chondrules and other components prod uced in the solar nebula.

M t thin th ch ch a v t ch t c ng v cc thnh ph n khc c u thnh tinh vn m ttr i.

Chondrulesmall, glassy spheres commonly found in meteorites.

M t kh i c u nh c c u trc v nh hnh tm th y ph bi n trong cc v n th ch.

Chromatic aberrationan optical lens defect causing color fringes, because the lens material brings different colors oflight to focus at different points.

Mu quang saiM t nh c i m c a th u knh quang h c l t o ra ra mu, v ch t li u c a th u knh

lm cho cc mu khc nhau c a nh sng h i t t i cc v tr khc nhau.


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Chromospherethe layer of the solar atmosphere that is located above the photosphere and beneath thetransition region and the corona. The chromosphere is hotter than the photosphere but not ashot as the corona.

Quy n s cM t l p c a b u kh quy n m t tr i n m trn quy n sng v bn d i vng chuy n ti p

v nh t hoa. Quy n s c nng h n quy n sng nh ng khng nng b ng nh t hoa.

Circumpolar Stara star that never sets but always stays above the horizon. This depends on the location of theobserver. The further South you go the fewer stars will be circumpolar. Polaris, the North Star,is circumpolar in most of the northern hemisphere.

Sao trn ng chn tr iM t ngi sao khng bao gi l n v lun n m pha trn ng chn tr i. i u ny ph

thu c vo v tr c a ng i quan st. Cng i ra sa h ng B c cng c t ngi sao trn ng

chn tr i. Sao B c C c, Sao Ph ng Nam, l nh ng ngi sao trn ng chn tr i h u h tbn c u b c.

Comaa spherical cloud of material surrounding the head of a comet. This material is mostly gas thatthe Sun has caused to boil off the comet's icy nucleus. This gas shines both by reflectedsunlight and light emitted by excited molecu les. A cometary coma can extend up to a millionmiles from the nucleus.

u sao ch iM t l p b i v t ch t hnh c u bao quanh u c a m t sao ch i. Nh ng v t ch t ny

h u h t l h i

Cometa chunk of frozen gasses, ice, and rocky debris that orbits the Sun. A comet nucleus is aboutthe size of a mountain on earth. When a comet nears the Sun, heat vaporizes the icy materialproducing a cloud of gaseous material surrounding the nucleus, called a coma. As the nucleusbegins to disintegrate, it also prod uces a trail of dust or dust tail in its orbital path and a gas orion tail pointing away from the Sun. Comet comas can extend up to a million miles from thenucleus and comet tails can be millions of miles long. There are thought to be literally trillionsof comets in our solar system out past Neptune and Pluto, but only once per decade or sodoes one become near and bright enough to see easily without binoculars or a telescope.


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Sao ch iM t kh i h i, bng v v n ng c ng c qu o vng quanh M t Tr i. Khi m t sao

ch i g n M t Tr i, h i nng lm b c h i v t ch t ng bng t o ra m t l p m t l p my khb i bao quanh nhn, g i l u sao ch i. Khi nhn b t u tan r, n ng th i t o ra m t v tb i hay ui b i trn qu o v m t ci ui kh hay ion ng c h ng v i M t Tr i. u saoch i c th v n ra hng ngn d m v ui sao ch i c th di hng ngn d m. Ng i ta tinr ng c c t t sao ch i trong h m t tr i chng ta bn ngoi sao H i V ng v DimV ng, nh ng ch kho ng m t sao ch i trn m t th p nin n g n v sng th y ddng m khng c n t i ng nhm hay knh vi n v ng.

Conjunctionan event that occurs when two or more celestial objects appear close close together in thesky.

Giao h iM t s ki n x y ra khi hai hay nhi u thin th xu t hi n g n nhau trn b u tr i.

Constellationa grouping of stars that make an imaginary picture in the sky. There are 88 constellations.

Chm saoM t nhm cc ngi sao c n i thnh hnh nh t ng t ng trn b u tr i. C 88

chm sao.

Convection Zonea layer in a star in which convection currents are the main mechanism by which energy istransported outward. In the Sun, a convection zone extends from just below the photosphereto about seventy percent of the solar radius.

Vng i l uM t l p trn m t ngi sao m s i l u l c ch chnh nng l ng c gi i

phng ra bn ngoi. Trong M t Tr i, vng i l u ch n m b d i quy n sng v chi mkho ng b y m i ph n trm bn knh m t tr i.

Convectionthe physical upwelling of hot matter, thus transporting energy from a lower, hotter region to ahigher, cooler region. A bubble of gas that is hotter than its surroundings expands and rises.When it has cooled by passing on its extra heat to its surroundings, the bubble si nks again.Convection can occur when there is a substantial decrease in temperature with height, suchas in the Sun's convection zone.


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S i l uHi n t ng nh ng v t ch t nng n i ln, ng th i mang nng l ng t vng th p

h n, nng h n ln vng cao h n, l nh h n. M t bong bng kh nng h n khu v c xungquanh n s n ra v n i ln. Khi n b lm l nh b ng cch truy n nhi t cho mi tr ng, bongbng s chm xu ng l i. i l u c th x y ra khi c s gi m st l n v nhi t theo cao,gi ng nh vng i l u c a M t Tr i.

Coronathe outermost layer of the solar atmosphere. The corona consists of a highly rarefied gas witha low density and a temperature greater than one million degrees Kelvin. It is visible to thenaked eye during a solar eclipse.

Nh t hoaL p ngoi cng c a b u kh quy n M t Tr i. Nh t hoa g m l p kh long c m t

th p v m t nhi t cao h n m t ngn Kelvin. N c th th y c b ng m t th ng khinh t th c.

Coronal Mass Ejectionsare huge bubbles of gas threaded with magnetic field lines that are ejected over the course ofseveral hours.They are often associated with solar flares and prominence eruptions .

Phun tro kh i l ng nh t hoa (dch t m)L nh ng bong bng kh l n cng v i ng s c t b n ra khng gian. N th ng i

cng v i s b ng sng v phun tro c a m t tr i. (ph n ny dch t m)

Cosmic Rayatomic nuclei (mostly protons) that are observe d to strike the Earth's atmosphere withextremely high amounts of energy.

Tia v trH t nhn nguyn t (h u h t l proton) c quan st th y chng va ch m vo b u kh

quy n tri t v i nng l ng c c l n.

Cosmic Stringa tubelike configuration of energy that is believed to have existed in the early universe. Acosmic string would have a thickness smaller than a trillionth of an inch but its length wouldextend from one end of the visible universe to the other.

Dy v trNng l ng c hnh ng c tin r ng c t n t i trong bu i s khai c a v tr . M t dy

v tr c th m ng h n m t t t inch nh ng chi u di c a n c th ko t u ny t i ukia c a v tr c th quan st c hi n t i


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Cosmologya branch of science that deals with studyin g the origin, structure, and nature of the universe.

V tr h cM t ngnh khoa h c nghin c u ngu n g c, c u trc, tnh ch t c a v tr .

Cratera bowl-shaped depression formed by the impact of an asteroid or meteoroid. Also thedepression around the opening of a volcano.

H thin th chM t vng t lm hnh chn t o ra b i ti u hnh tinh hay thin th ch. y c ng l vng

t lm xu ng xung quanh m t mi ng ni l a.

Crystallineindicates a rock is composed of mineral crystals rather than glass. In g eneral, when igneous

melts cool very fast they form glass (like obsidian), but when they cool slower, mineral crystalshave an opportunity to grow.

Tinh thCh r ng m t hn c c u t o b i cc ch t c c u trc tinh th h n l v nh hnh.

Thng th ng, khi b nung nng r t nhanh chng tr thnh v nh hnh (nh obsidian m tlo i khong ch t), nh ng khi b nung ch m h n, cc ch t c c u trc tinh th c c h i pht tri n l n h n.

DDark Mattera term used to describe matter in the universe that cannot be seen, but can be detected by itsgravitational effects on other bodies.

V t ch t t iM t thu t ng dng ch nh ng v t ch t trong v tr khng nhn th y c, nh ng c

th pht hi n ra chng b i tc ng h p d n c a chng ln cc v t th khc.

Declinationthe angular distance of an object in the sky from the celestial equator.

l chGc c a m t thin th v i ng xch o b u tr i.


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Densitythe amount of matter contained within a given volume. Density is measured in grams per cubiccentimeter (or kilograms per liter). The density of water is 1.0, iron is 7.9, and lead is 11.3.

Kh i l ng ringL ng v t ch t ch a trong m t n v th tch. Kh i l ng ring c o b ng gam

trn m t centimet vun ( hay kilogam trn lt). Kh i l ng ring c a n c l 1,0, s t l 7,9, vch l 11,3.

Differentiatedwhen a (partially) molten body has been divided into two or more fractions of dissimilarcompositions. In the case of the Earth, iron -nickel metal was differentiated from silicatematerial to form the planet's core.

Phn tch (dch t m)Khi m t v t b n u ch y (m t ph n) s b chia thnh hai hay nhi u ph n c c u trc

khng ng d ng. Trong tr ng h p Tri t, kim lo i s t-niken c phn tch t h p ch t

silicat t o ra nhn c a hnh tinh.

Diskthe surface of the Sun or other celestial body projected against the sky.

a (dch t m)B m t c a M t Tr i hay cc thin th khc h ng ng c l i b u tr i.

Doppler Effectthe apparent change in wavelength of sound or light emitt ed by an object in relation to anobserver's position. An object approaching the observer will have a shorter wavelength (blue)while an object moving away will have a longer (red) wavelength. The Doppler effect can beused to estimate an object's speed and direction.

Hi u ng DopplerS thay i c a b c sng m thanh hay nh sng pht ra b i m t v t th ph thu c

vo v tr ng i quan st. M t v t th i l i g n ng i quan st s c b c sng ng n h n(xanh) khi m t v t i ra xa s c b c sng di h n ( ). Hi u ng Doppler c th c dng c l ng t c v v tr c a m t v t th .

Double Stara grouping of two stars. This grouping can be apparent, where the stars seem close together,or physical, such as a binary system.

Sao iM t nhm 2 ngi sao. Nhm ny c th g n nhau v m t quan st, hay v t l, nh h

nh phn.


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Double Asteroidtwo asteroids that revolve around each other and are held together by the gravity betweenthem. Also called a binary asteroid.

Ti u hnh iHai ti u hnh tinh quay quanh nhau v c gi l i v i nhau b ng m t tr ng l c gi

chng. Chng cn c g i l ti u hnh tinh nh phn.

Dust grainsnot the dust one finds around the house, which is typically fine bits of fabric, dirt, or dead skincells. Rather interstellar dust grains are much smaller clumps, on the order of a fraction of amicron across, irregularly shaped, and composed of carbon and/or silicates. Dust is mostevident by its absorption, causing large dark patches in regions of our Milky Way Galaxy anddark bands across other galaxies.

B i v tr

Khng ph i l b i tm th y trong nh, th ng l nh ng m u nh c a v i, t, hay tbo da ch t. Gi a cc v sao b i v tr nh h n t nhi u, c m t ph n nh c a m tmicromet, hnh d ng khng u, v c ch a cacbon v/ho c silicat. B i v tr c pht hi nh u nh b i s h p th c a chng, t o ra nh ng kho ng t i trong D i Ngn H c a chng tav nh ng d i t i trong nh ng thin h khc.

EEclipsethe total or partial blocking of one celestial body by another.Thin th cHI n t ng m t thin th che khu t m t ph n hay ton b thin th khc.

Ejectamaterial from beneath the surface of a body such as a moon or planet that is ejected by animpact such as a meteor and distributed around the surface. Ejecta usually appears as a

lighter color than the surrounding surface.

V t phngV t ch t bn d i b m t c a m t thin th nh m t trng hay hnh tinh c phng

ra ngoi b i m t s va ch m c a sao bng v lan ra kh p b m t. V t phng th ng xu thi n v i mu s c sng h n b m t xung quanh.


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Ellipsean ellipse is an oval shape. Johannes Kepler discovered that the orbits of the planets wereelliptical in shape rather than circular.

ElipElip l hnh van. Johannes Kepler pht hi n ra r ng qu o c a m t hnh tinh l

d ng elip ch khng ph i trn.

Elliptical Galaxya galaxy whose structure shaped like an ellipse and is smooth and lacks complex structuressuch as spiral arms.

Thin h elipM t thin h m d ng elip c a n r rng v khkoong c nh ng c u trc ph c t p nh

cc nhnh xo n c.

Elongationthe angular distance of a planetary body from the Sun as seen from Earth. A planet at greatesteastern elongation is seen in the evening sky and a planet at greatest western elongation willbe seen in the morning sky.

Ly gicGc xa c a m t hnh tinh v i Mt Tr i khi nhn t Tri t. M t hnh tinh ly gic pha

ng c th y trn b u tr i ban m v m t hnh tinh c ly gic pha ty s c th y vob u tr i bu i sng.

Emission nebulaa type of nebula that shi nes by emitting light when electrons recombine with protons to formhydrogen atoms. The electron frequently approaches the proton in steps emitting energy aslight as it gets pulled in. In one of the most common "steps," the recombining electron emits aphoton of red light. Since many atoms in the nebula do this all at once, the nebula appears redin color. This type of nebula is created when energetic ultraviolet light from a hot star shineson a cloud of hydrogen gas, stripping away electrons from the ato ms (ionization). The freeelectrons can then begin the process of recombination.

Tinh vn sngKi u tinh vn t a sng b ng cch pht ra nh sng khi m t electron ti t h p v i

proton t o ra nguyn t hydro. Th ng electron t i g p proton t o ra n c nng l ng nhnh sng khi n b ht vo. M t trong nh ng n c ph bi n nh t, s ti t h p electron t o ram t photon thu c nh sng . Khi nhi u nguyn t c a tinh vn cng m t lc c hi n t ngnh v y, tinh vn s c mu . Lo i tinh vn ny c t o ra khi tia c c tm nng l ng caopht ra t m t ngi sao nng trong m my khi hydro, tch electron kh i nguyn t (ionha). Nh ng electron t do c th b t u qu trnh ti t h p.


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Energy Fluxthe rate of flow of energy through a reference surf ace. In cgs units, measured in erg s -1. Alsomeasured in watts, where 1 watt = 1 x 107 erg s -1. Flux density, the flux measured per unitarea, is also often referred to as "flux".

Thng l ng nng l ngL ng nng l ng truy n qua m t di n tch cho tr c. Trong h cgs, c o b ng

erg s-1. ng th i c ng c o b ng watt, v i 1 watt = 1 x 10^7 erg s -1. M t thngl ng, thng l ng o trong m t n v di n tch, thng th ng c ng c quy v thngl ng.

Enstatitea type of primitive chondrite. That chondrite is dominated by the silicate mineral enstatite.

Khong enxtatitM t lo i c a chondrite c (xem chondrite). Lo i chondrite ny ch y u t o t khong

enxtatit silicat.

Ephemerisa table of data arranged by date. Ephemeris tables are typica lly to list the positions of the Sun,Moon, planets and other Solar System objects.

Lch thin vnB ng thng tin s p x p theo ngy. Lch thin v n ch y u ghi l i v tr c a M t Tr i, M t

Trng, cc hnh tinh v nh ng thin th khc c a H M t Tr i.

Equinoxthe two points at which the Sun crosses the celestial equator in its yearly path in the sky. Theequinoxes occur on or near March 21 and September 22. The equinoxes signal the start of theSpring and Autumn seasons.

im phnHai v tr m t i M t Tr i i qua ng xch o b u tr i trn con ng hng nm

c a n trn b u tr i. i m phn xu t hi n vo g n 21 Thng Ba v 22 Thng Chn. i mphn l d u hi u b t u Ma Xun v Ma Thu.

Erga cgs unit of energy equal to work done by a force o f 1 dyne acting over a distance of 1 cm.107 (ten million) erg s-1 (ergs per second) = 1 watt. Also, 1 Calorie = 4.2 x 1010 (42 billion)ergs.


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ErgM t n v cgs o nng l ng b ng m t l c c l n 1 yn tc d ng trong qung

ng l 1 cm.10^7 erg s-1 (erg trn giy) = 1 wat. ng th i, 1 Calo = 4,2 x 10^10 (42 t) erg.

Escape Velocitythe speed required for an object to escape the gravitational pull of a planet or other body.

V n t c thotT c c n thi t m t v t th thot kh i l c h p d n c a m t hnh tinh hay thin th

khc.

Event Horizonthe invisible boundary around a black hole past which nothing can escape the gravitationalpull - not even light.

Chn tr i s ki nVng bin gi i v hnh xung quanh m t l en m n u v t qua khng c g c ththot kh i l c h p d n k c nh sng.

Evolved Stara star that is near the end of its life cycle where most of its fuel has been used up. At this pointthe star begins to loose mass in the form of stellar wind.

Sao ti n haM t ngi sao khi n g n cu i vng i c a mnh th h u h t nhin li u c s

d ng h t. T i v tr ny ngi sao b t u b n ra kh i l ng b ng d ng gi sao.

Extragalactica term that means outside of or beyond our own galaxy.

Ngoi thin hThu t ng mang ngha bn ngoi hay ngoi gi i h n c a thin h chng ta.

Extraterrestriala term used to describe anything that does not originate on Earth.

Ngoi Tri tM t thu t ng ch b t c th g khng c ngu n g c trn Tri t.


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Eyepiecethe lens at the viewing end of a telescope. The eyepiece is responsible for enlarging theimage captured by the instrument. Eyepieces are available in different powers, yieldingdiffering amounts of magnification.

Th knhTh u knh n m pha nhn c a m t knh thin vn. Th knh c nhi m v phng to hnh

nh thu c t d ng c . Th knh c tiu c khc nhau, mang l i phng i khc nhau.

FFaculaebright patches that are visible on the Sun's surface, or photosphere.

V t sng trn M t Tr iNh ng v t sng c th th y c trn b m t hay quang quy n (quy n s c) c a M t

Tr i.

Filamenta strand of cool gas suspended over the photosphere by magnetic fields, which appears darkas seen against the disk of the Sun.

Dy (dch t m)M t dng kh l nh l l ng trn quang quy n do tc ng c a t tr ng, chng l mu

en khi nhn vo a M t Tr i.

Findera small, wide-field telescope attached to a larger telescope. The finder is used to help pointthe larger telescope to the desired viewing location.

Knh ng m m c tiuM t knh vi n v ng nh , t m nhn r ng c g n vo m t knh vi n v ng l n h n. Knh

ng m dng h ng knh vi n v ng l n v khu v c mu n ng m.

Fireballan extremely bright meteor. Also known as bolides, fireballs can be several times b righter thanthe full Moon. Some can even be accompanied by a sonic boom.

C u l aL m t sao bng c c sng. c bi t t i nh n l a, c u l a c th sng h n M t

Trng trn vi l n. M t s cn c th i cng v i ti ng n do ma st v i khng kh.


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Flare (Solar)rapid release of energy from a localized region on the Sun in the form of electromagneticradiation, energetic particles, and mass motions.

Bng n (M t Tr i)S gi i phng nng l ng t m t vng no trn M t Tr i b ng d ng b c x i n t ,

nh ng h t mang nng l ng l n, v kh i l ng di ng.

Flare Stara member of a class of stars that show occasional, sudden, unpredicted increases in light. Thetotal energy released in a flare on a flare star can be much greater that the energy release d ina solar flare.

Sao bng n (dch t m)M t thnh vin trong nhm sao thnh tho ng c s chi sng b t ng , khng d on

c. T ng nng l ng c gi i phng ra trong m t l n bng n c a m t ngi sao bng nc th l n h n c nng l ng c gi i phng c a s bng n trn M t Tr i.

Footpointthe intersection of magnetic loops with the photosphere.

i m giao nhau c a cc mc t v i quang quy n.

Free Electronan electron that has broken free of it's atomic bond and is therefore not bound to an atom.

Electron t doM t electron thot ra hng ro nguyn t v nh v y n khng b tri bu c v i

nguyn t n a.

Frequencythe number of repetitions per unit time of the oscillations of an electromagnetic wave (or otherwave). The higher the fre quency, the greater the energy of the radiation and the smaller thewavelength. Frequency is measured in Hertz.

T n sL ng l p l i trn m t n v th i gian c a m t sng i n t (hay cc sng khc). T n

s cng l n, nng l ng c a sng cng nhi u v b c sng cng ng n. T n s c ob ng Hertz.


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Fusiona process where nuclei collide so fast they stick together and emit a great deal of energy. Inthe center of most stars, hydrogen fuses together to form helium. Fusion is so powerful itsupports the star's enormous mass from collapsing in on itself, and heats the star so high itglows as the bright object we see today.

Ph n ng nhi t h chQu trnh cc h t nhn va ch m nhau qu m nh n n i chng dnh vo nhau v t o ra

m t nng l ng r t l n. Trong nhn h u c a h u h t cc ngi sao, hydro k t h p v i nhau t o helium. Ph n ng nhi t h ch m nh n n i ngn khng cho kh i l ng ngi sao lm s pchnh n, v s c nng c a n l n t i n i n pht sng nh m t v t th sng m chng ta th yngy nay.

GGalactic Nucleusa tight concentration of stars and gas found at the innermost regions of a galaxy. Astronomersnow believe that massive black holes may exist in the center of many galaxies.

Nhn thin hM t m t dy c cc sao v kh c tm th y gi a m t thin h. Cc nh thin

vn h c ngy nay tin r ng cc l en l n c th t n t i trung tm nhi u thin h.

Galactic Halo

the name given to the spherical region surrounding the center, or nucleus of a galaxy.

Qu ng bao quanh thin hTn c s d ng ch khu v c hnh c u quanh trung tm, hay nhn c a m t thin

h

Galaxya large system of about 100 billion stars. Our Sun is a member of the Milky Way Galaxy.There are billions of galaxies in the observable universe. Exactly when and how galaxiesformed in the Universe is a topic of current astronomical research.Galaxies are found in a variety of sizes and shapes. Our own Milky Way galaxy is spiral inshape and contains several billion stars. Some galaxies are so distant their light t akes millionsof years to reach the Earth. Galaxies are classified in three main groups; spirals, ellipticals andirregulars.


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Giant Molecular Cloud (GMC)massive clouds of gas in interstellar space composed primarily of hydrogen molecules. Theseclouds have enough mass to produ ce thousands of stars and are frequently the sites of newstar formation.

m my nguyn t kh ng l (dch t m)m my kh kh i l ng ln trong khng gian gi a cc ngi sao c c u t o ch y u

t cc nguyn t hydro. Nh ng m my ny c kh i l ng l n t o ra hng ngn ngisao v th ng xuyn l a i m hnh thn cc ngi sao m i.

Globular Clustera tight, spherical grouping of hundreds of thousands of stars. Globular clusters are composedof older stars,and are usually found around the cen tral regions of a galaxy.

Cung sao c uM t nhm dy c, hnh c u g m hng trm ngn sao. Cung sao c u c hnh thnh

t cc sao gi, v th ng c tm thy quanh vng trung tm c a m t thin h.

Granulationa pattern of small cells that can be seen on the surface of the Sun. They are caused by theconvective motions of the hot gases inside the Sun.

H t (dch t m)M t lo i ph n t nh c th th y trn b m t M t Tr i. Chng c t o ra do s i

l u kh nng trong lng M t Tr i.

Gravitational Lensa concentration of matter such as a galaxy or cluster of galaxies that bends light rays from abackground object. Gravitational lensing results in duplicate images of distant objects.

Th u knh h p d nM t s t p trung v t ch t nh m t thin h hay m thin h b cong ng i nh

sng c a v t th pha sao. Th u knh h p d n gy t o ra 2 nh c a m t v t xa.

Gravitya mutual physical force of nature that causes two bodies to attract each other.

H p d nM t l c v t l chung c a t nhin gy ra hi n t ng 2 v t th ht l n nhau.


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Greenhouse Effectan increase in temperature caused when incoming solar radiation is passed but outgoingthermal radiation is blocked by the atmosphere. Carbon dioxide and water vapor are two ofthe major gases responsible for this effect.

Hi u ng nh knhS tng nhi t gy ra do nh sng t M t Tr i i vo c nh ng nh sng i ra b

ngn b i t ng kh quy n. Cacbon dioxit v h i n c l 2 kh ch y u gy ra hi n t ng ny.

HHeliocentricsun centered.

Nh t tm o t tm M t Tr iTrung tm M t Tr i

Heliopausethe point at which the solar wind meets the interstellar medium or solar wind from other stars.

V tr m t i gi M t Tr i g p mi tr ng gi a cc ngi sao ho c gi t cc ngi saokhc

Heliospherethe space within the broundary of the heliopause containing the Sun and solar system.

Vng khng gian bin gi i c a heliopause ch a M t Tr i v H M t Tr i.

Heliumthe second lightest and second most abundant element. The typical helium ato m consists of anucleus of two protons and two neutrons surrounded by two electrons. Helium was firstdiscovered in our Sun. Roughly 25 percent of our Sun is helium.

HeliNguyn t nh th nh v nhi u th nh. Nguyn t helium ch a m t nhn g m 2

proton v 2 notron quay quanh b i 2 electron. Heli c tm th y u tin M t Tr i. Kho ng25 ph n trm M t Tr i l heli.


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Hemispherea half of the celestial sphere that is divided into two halves by either the horizon, the celestialequator, or the ecliptic.

N a thin c uM t n a c a thin c u, n c chi i b i c ng chn tr i, ng xch o b u

tr i, hay m t ph ng hong o.

Hertzabbreviated Hz. A unit of frequency equal to one cycle per second. One kHz = 1000 Hz. OneMHz = 106 (one mill ion) Hz. One GHz = 109 Hz.

HertzVi t t t l HZ. M t n v t n s b ng m t vng trn trn giy. M t kHz = 1000 Hz. M t

MHz = 106 (m t ngn) Hz. M t GHz = 109 Hz.

H II regiona region of hot gas surrounding a young star or stars that is mostly ionized . The energetic lightfrom these young stars ionizes the existing gas. This region typically appears red as it glowswith the photons emitted when elections recombine with hydrogen protons.

Vng H IIM t vng kh nng bao b c quanh m t ngi sao tr hay nh ng ngi sao ion ha g n

nh hon ton. nh sng giu nng l ng t nh ng ngi sao tr ion ha kh. Vng ny bnhth ng c mu v n gi i phng phtn khi electron k t h p l i v i h t nhn hydro.

Hot Spotcenter of persistent volcanism, thought to be the surface expression of a rising hot plume inEarth's mantle.

i m nngTrung tm c a m t ni l a phun lin t c, gi ng nh b m t b p c a m t chm lng v

nng lan ra trn v Tri t.

Hour Anglethe telescope based coordinate specifying t he angle, in the equatorial plane, from the meridianto a plane containing the celestial object and the north and south celestial poles.

Gc gi (dch t m)Knh thin vn d a trn t a gc, trong m t ph ng xch o, t nh t i xch o

ch a cc thin th v t c c b c t i c c nam.


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H-R DiagramThe Color-Magnitude Diagram is a graph upon which stars are plotted by spectral type andactual luminosity. It is named for the two scientists Russell and Hertzsprung who first used it in1913.

Bi u H-RBi u Mu- l n l m t bi u trn cc ngi sao c v b ng quang ph v

sng th c t . N c t tn theo tn hai nh bc h c Russell v Hertzsrung hai ng is d ng l n u vo nm 1913.

Hubble's Lawthe law of physics that states that the farther a galaxy is from us, the faster it is moving awayfrom us.

nh lu t Hubblenh lu t trong v t l ni r ng nh ng thin h cng xa chng ta, chng tch xa chng ta

cng nhanh.

Hydrogenthe lightest and most abundant element. A hydrogen atom consists of one proton and oneelectron. A hydrogen nucleus is just a single proton. Hydrogen composes about 75 percent ofthe Sun but only a tiny fraction of the Earth. Hydrogen is the building block of the universe.Stars form from massive clouds of hydr ogen gas.

HydroNguyn t nh nh t v ph bi n nh t. M t nguynt hydro ch a m t proton v m t

electron. H t nhn hydro ch l m t proton. Hydro chi m kho ng 75 ph n tr m M t Tr i nh ng

ch chi m m t ph n nh Tri t. Hydro l vin g ch c a v tr . Cc ngi sao hnh t hnh tnh ng m my n ng y kh hydro.

Hydromagnetic Wavea wave in which both the plasma and magnetic field oscillate.

Sng th y ng h cM t sng m c plasma v t tr ng u dao ng.

Hypergalaxya system consisting of a spiral galaxy surrounded by several dwarf white galaxies, oftenellipticals. Our galaxy and the Andromeda galaxy are examples of hypergalaxies.

C c siu thin h (dch t m)M t h th ng g m m t thin h xo n c c bao b c b i vi thin h ln tr ng, thong

th ng l d ng elip. Thin h c a chng ta v thin h Andromeda l nh ng v d c a c csin thin h.


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Ionospherethe region of the Earth's upper atmosphere containing a small percentage of free electronsand ions produced by photoioni zation of the constituents of the atmosphere by solar ultravioletradiation. The ionosphere significantly influences radiowave propagation of frequencies lessthan about 30 MHz. In Earth's atmosphere, the ionosphere begins at an altitude of about 25miles and extends outward about 250.

T ng i n lyVng khng gian trong t ng trn c a tng kh quy n ch a m t l ng ph n trm nh

electron t do v ion uocj t o ra b ng quang ion ha b i cc ph n t c a b u kh quy nv i tia c c tm c a M t Tr i. T ng i n ly c nh h ng ng k t i vi c truy n sng radio ct n s th p h n 39 MHz. Trong b u kh quy n c a Tri t, t ng i n ly b t u caokho ng 25 d m so v i m c n c bi n v m r ng ln 250 d m.

Iron Meteoritea meteorite which is composed mainly of iron mixed with smaller amount s of nickel.

Thin th ch s tM t thin th ch c thnh ph n ch y u l s t tr n v i m t t niken.

Irregular Galaxya galaxy with no spiral structure and no symmetric shape. Irregular galaxies are usuallyfilamentary or very clumpy in shape.

Thin h v nh hnhM t thin h khng c d ng xo n c v khng c hnh dng i x ng. Thin h v nh

hnh thng th ng c d ng s i hay nh m t m l n x n.

Isotopeone of two or more atoms having the same number of protons in its nucleus, but a differ entnumber of neutrons and, therefore, a different mass.

Ch t ng vM t trong hai hay nhi u nguyn t c cng s proton trong h t nhn, nh ng l i c s

notron khc nhau v, v v y, c kh i l ng khc nhau.


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JJovian planetany of the four outer, gaseous planets: Jupiter, Saturn, Uranus, and Neptune.

Hnh tinh bn ngoiCc hnh tinh kh pha ngoi: Sao M c, Sao Th , Sao Thin V ng, v Sao H i

V ng.

Julian Date (JD)the interval of time in days and fraction of a day since 1 January 4713 BC, Greenwich noon.

Ngy JulianKho ng th i gian trong cc ngy v m t ph n trong ngy t ngy 1 thng 1 4713 tr c

cng nguyn, bu i tr a Greenwich.

KKelvina temperature scale used in sciences such as astronomy to measure extremely coldtemperatures. The Kelvin temperature scale is just like the Celsius scale except that thefreezing point of water, zero degrees Celsius, is equal to 273 degrees Kelvin. Absolute zero,the coldest known temperature, is reached at 0 degrees Kelvin or -273.16 degrees Celsius.

KenvinThang o nhi t dng trong khoa h c nh thin vn h c o nhi t r t th p.

Thang nhi t Kenvin gi ng thang Celsius ch tr i m ng c a n acs, khng Celsius,b ng 273 Kenvin. Khng tuy t i, nhi t l nh nh t, t 0 Kenvin hay -273,16 Celsius.

Kepler's Second Lawa ray directed from the Sun to a planet sweeps out equal areas in equal times.

nh lu t 2 Kepler

M t ng th ng n i t M t Tr i t i m t hnh tinh qut qua cc di n tch b ng nhautrong nh ng th i gian b ng nhau.

Kepler's First Lawa planet orbits the Sun in an ellipse with the Sun at one focus.

nh lu t 1 KeplerQu o c a m t hnh tinh quanh M t Tr i l hnh elip v i M t Tr i l m t tm.


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Kepler's Third Lawthe square of the period of a planet's orbit is pro portional to the cube of that planet'ssemimajor axis; the constant of proportionality is the same for all planets.

nh lu t 3 KeplerBnh ph ng chu k qu o c a m t hnh tinh b ng l p ph ng c a n a tr c l n; t

l c nh gi ng nhau v i m i hnh tinh.

keVone thousand electron volts.

keVM t ngn electron vn.

Kilometer

abbreviated km. 1 km = 1000 meters = 105 cm = 0.62 mile.

KilometVi t t t km. 1 km = 1000 met = 10^5 cm = 0,62 d m.

Kiloparseca distance equal to 1000 parsecs.

KiloparsecKho ng cch b ng 1000 parsec.

Kirkwood Gapsregions in the main belt of asteroids where few or no asteroids are found. They were namedafter the scientist who first noticed them.

Kirkwood GapsVng trong vnh ai ti u hnh tinh chnh m c t ho c khng c ti u hnh tinh

no c tm th y. N c t tn cho nh bc h c u tin th y chng.

Kuiper Belta large ring of icy, primitive objects beyond the orbit of Neptune. Kupier Belt objects arebelieved to be remnants of the origi nal material that formed the Solar System. Someastronomers believe Pluto and Charon are Kuiper Belt objects.


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Vnh ai KuiperM t vnh ai bng, cc v t th nh bn ngoi qu o c a Sao H i V ng. Cc thin

th c a Vnh ai Kuiper c tin l ph n cn l i c a nh ng v t ch t nguyn th y hnh thnhnn H M t Tr i. M t s nh thin vn h c tin r ng Sao Dim V ng v Charon l nh ngthin th c a Vnh ai Kuiper

LLagrange Pointfrench mathematician and astronomer Joseph Louis Lagrange showed that three bodies canlie at the apexes of an equilateral triangle which rotates in its plane. If one of the bodies issufficiently massive compared with the other two, then the triangular configuration isapparently stable. Such bodies are sometimes referred to as Trojans. The leading apex of thetriangle is known as the leading Lagrange point or L4; the trailing apex is the trailing Lagrangepoint or L5.

i m LagrangeNh ton h c v thin vn h c ng i Php Joseph Louis Lagrange ch ng minh l 3

thin th c th n m trn 3 nh c a m t tam gic u v quay quanh m t ph ng c a n. N um t thin th l n h n 2 thin th kia th c u trc tam gic kh ch c ch n. Cc thin th nhi ukhi gi ng Trojans. nh d n u c a tam gic c g i l i m Lagrange d n u hay L4;nh ui l nh Lagrange ui hay L5.

Lavamolten rock that is erupted onto the sur face of a planet and is hot enough to flow.

Dung nham nng ch y c b n ra b m t m t hnh tinh v nng ch y.

Lenticular Galaxya disk-shaped galaxy that contains no conspicuous structure within the disk. Lenticulargalaxies tend to look more like elliptical galaxies than spiral galaxies.

Thin h h t uM t thin h hnh a khng ch a nh ng c u trc d th y trn . Thin h h t u

gi ng thin h elip h n l thin h xo n c.

Librationan effect caused by the apparent wobble of the Moon as it orbits the Earth. The Moon alwayskeeps the same side toward the Earth, but due to libration, 59% of the Moon's surface can beseen over a period of time.


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Bnh ng - l c lHi n t ng gy ra b i s thay i hnh dng c a M t Trng khi n quay quanh Tri

t. M t Trng lun h ng m t m t v pha Tri t, nh ng nh hi n t ng ny, 59% bm t M t Trng c th th y c sau m t th i gian.

Light Yearthe distance light travels in a year, at the rate of 300,000 kilometers per second (671 millionmiles per hour); 1 light -year is equivalent to 9.46053e12 km, 5,880,000,000,000 miles or63,240 AU.

Nm nh SngKho ng cch nh sng i c trong m t nm, v i t l 300.000 kilomet trn giy (671

ngn d m trn gi ); 1 nm nh sng b ng 9,46053e12 km, 5.880.000.000.000 d m hay63.240 AU.

Limb

the outer edge or border of a planet or other celestial body.

Qu ngBn ngoi ra c a m t hnh tinh hay thin th khc.

Local Groupa small group of about two dozen galaxies of which our own Milky Way galaxy is a member.

Nhm a ph ngM t nhm nh c hai t thin h m D i Ngn H c a ch ng ta c ng l m t thnh

vin.

Luminositythe amount of light emitted by a star.

sngL ng nh sng pht ra t m t ngi sao.

Lunar Eclipsea phenomenon that occurs when the Moon passes into the shadow of the Earth. A partiallunar eclipse occurs when the Moon passes into the penumbra, or partial shadow. In a totallunar eclipse, the Moon passes into the Earth's umbra, or total shadow.

Nguy t th cM t hi n t ng x y ra khi M t Trng i vo bng c a Tri t. Nguy t th c m t ph n

x y ra khi M t Trng i vo vng bng n a t i. Trong nguy t th c ton ph n, m t trng i vovng bng t i hon ton c a Tri t.


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Lunar Monththe average time between successive new or full moons. A lunar month is equal to 29 days 12hours 44 minutes. Also called a synodic month.

Thng m lchM t kho ng th i gian trung bnh c a trng m i hay trng trn k ti p nhau. M t thng

trng b ng 29 ngy 12 gi 44 pht. Cn c g i l thng tn gio.

Lunationthe interval of a complete lunar cycle, between one new Moon and the next. A lunation isequal to 29 days, 12 hours, and 44 minutes.

Thng m lch (nh trn)

MMarelatin word for "sea." Galileo thought the dark featureless areas on the Moon were bodies ofwater, even though the Moon is essentially devoid of liquid water. The term is still applied tothe basalt-filled impact basins common on the face of the Moon visible from Earth.

MareT latin ngha l bi n. Galileo ngh r ng b m t khng c ng nt r rng mu t i

trn M t Trng l n c, m c d trn M t Trng khng h t n t i m t gi t n c l ng no.

Thu t ng trn v n c ch p nh n cho nh ng vng lng ch o ph y bazan kh ph bi ntrn m t th y c a M t Trng khi nhn t Tri t.

Magellanic Cloudstwo small, irregular galaxies found just outside our own Milky Way galaxy. The Magellanicclouds are visible in the skies of the southern hemisphere.

m my MagellanicHai thin h nh , v nh hnh tm th y ngoi D i Ngn H c a chng ta. Hai m

my Magellanic c th th y c b u tr i bn c u nam.

Magnetic Fielda field of force that is generated by electric currents. The Sun's average large -scale magneticfield, like that of the Earth, exhibits a north and a south pole linked by lines of magnetic force.

T tr ngM t tr ng l c c t o ra b i dng i n. a t tr ng l n c a M t Tr i, gi ng nh

Tri t, ch y t c c b c xu ng c c nam v c n i b i ng s c t .


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Magnetic Field Linesimaginary lines that indicate the strength and direction of a magnetic field. The orientation ofthe line and an arrow show the direction of the field. The lines are drawn closer togetherwhere the field is stronger. C harged particles move freely along magnetic field lines, but areinhibited by the magnetic force from moving across field lines.

ng s c tM t ng t ng t ng bi u th l n v v tr c a t tr ng. H ng c a ng v

m t m i tn ch h ng c a t tr ng. Nh ng ng s c t c v cng g n nhau th ttr ng cng m nh. Nh ng ph n t mang i n di chuy n t do d c theo ng s c t , nh ngl c t ngn khng cho chng di chuy n ngang qua cc ng s c t .

Magnetic Poleeither of two limited regions in a magnet at which the magnet's field is most intense.

C c t

C hai u c a m t nao chm m t tr ng m nh nh t.

Magnetospherethe area around a planet most affected by its magnetic field. The boundary of this field is setby the solar wind.

Quy n tKhng gian xung quanh m t hnh tinh chu nh h ng ch y y u b i t tr ng c a n.

Ra c a n c nh hnh b i gi M t Tr i.

MagnitudeThe degree of brightness of a star or other object in the sky according to a scale on which thebrightest star has a magnitude -1.4 and the faintest visible star has magnitude 6. Sometimesreferred to as apparent magnitude. In this scale, each number is 2.5 times the brightness ofthe previous number. Thus a star with a magnitude of 1 is 100 times brighter than on with avisual magnitude of 6.

sng sng c a m t ngi sao hay cc thin th khc trn b u tr i d a trn m t th c o

m trong ngi sao sng nh t c sng l -1,4 v ngi sao m nh t c sng l 6. ikhi c quy thnh sng bi u ki n. Trong thang o ny, m i s c sng g p 2,5 l n str c. V d m t ngi sao c sng1 s sng h n 100 l n ng iao c sng 6.

Magmavery hot, fluid rock. Magma is used to describe molten rock both below and on top of thesurface of a planet and thus is a more general term than lava. Magma may contain solidmineral crystals which are suspended in the melt.


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Meridianan imaginary circle drawn through the North and South poles of the celestial equator.

Thin nhM t ng trn t ng t ng v qua c c B c v c c Nam c a xch o b u tr i.

Messier, Charleswhile hunting for comets in the skies above France, 18th century astronomer Charles Messiermade a list of the positions of about 100 fuzzy, diffuse looking objects which appeared at fixedpositions in the sky. Although these objects looked like comets, Messier knew that since theydid not move with respect to the background stars they could not be the undiscovered cometshe was searching for. These objects are now well known to modern astronomers to be amongthe brightest and most striking gaseous nebul ae, star clusters, and galaxies. Objects onMessier's list are still referred to by their "Messier number". For example the AndromedaGalaxy, the 31st object on the list, is known as M31.

Charles MessierTrong khi ang sn tm sao ch i trn b u tr i n c Php, nh thin vn h c th k 18

Charles Messier l p m t b n danh sch kho ng 100 thin th m nh t, di xu t hi n nh ng v tr c dnh trn b u tr i. M c d nh ng thin th ny trng gi ng nh sao ch i,Messier bi t r ng n u chng khng di chuy n so v i nh ng ngi sao trn n n tr i th chngkhng th l nh ng ngi sao ch i m ng ta ang tm ki m. Nh ng thin th ny c bi tkh r i v i nh ng nh thin vn h c hi n i l nh ng tinh vn kh, c m sao, v thin hsng nh t v n t ng nh t. Nh ng thin th trong danh sch c a Messier v n c gi tnl th t Messier. V d Thin h Andremeda, thin th th 31 trong danh sch, c tn lM31.

Metamorphic rocka rock that has been heated and compressed so that it recrystallizes, but does not melt.

bi n ha (dch t m) b nung nng v b nn nh v y n hnh thnh tinh th , nh ng khng nng ch y.

Meteora small particle of rock or dust that burns away in the Earth's atmosphere. Meteors are alsoreferred to as shooting stars.

Sao bngM t m u nh c a hay b i chy trong trong b u kh quy n c a Tri t g i l sao

bng.

Meteor Showeran event where a large number of meteors enter the Earth's atmosphere from the same


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direction in space at nearly the same time. Most meteor showers t ake place when the Earthpasses through the debris left behind by a comet.

M a sao bngM t s ki n c m t l ng l n sao bng i vo b u kh quy n Tri t cng m t n i

g n nh cng m t lc. H u h t m a sao bng x y ra khi Tri t i qua ph n kh b i do m tsao ch i l i.

Meteoritean object, usually a chunk or metal or rock, that survives entry through the atmosphere toreach the Earth's surface. Meteors become meteorites if they reach the ground.

Thin th chM t thin th , th ng l m t kh i kim lo i ho c , v n cn t n t i khi i qua b u kh

quy n v ch m b m t Tri t. Thin th ch tr thnh v n th ch n u chng ch m t i m t t.

MeVone million electron volts.

MeVM t nghn electron von.

Millibara measure of atmospheric pressure equal to 1/1000 of a bar. Standard sea -level pressure onEarth is about 1013 millibars.

MilibarM t n v o p su t khng kh b ng 1/1000 bar. p su t trung bnh c a m c n c

bi n trn Tri t b ng 10e3 milibar.

Minor Planetanother name used to describe a large asteroid.

Hnh tinh nhTn g i khc c a ti u hnh tinh c kch th c l n.

Molecular Cloudan interstellar cloud of molecular hydrogen containing trace amounts of other molecules suchas carbon monoxide and ammonia.

My phn tM t m my phn t hydro gi a cc v sao ch a m t t cc phn t khc nh cacbon

monoxit v amoniac.


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NNadira term used to describe a point directly underneath an object or body.

M t thu t ng ch m t i m ngay bn d i m t v t th .

Nebulaa cloud of dust and gas in space, usually illuminated by one or more stars. Nebulae representthe raw material the stars are made of.

Tinh vnM t m my kh v b i trong v tr , th ng c chi u sng b i m t hay nhi u ngi

sao. Tinh vn l v t li u th hnh thnh ra cc v sao.

Neutrinoa fundamental particle supposedly produced in massive numbers by the nuclear reactions instars; they are very hard to detect because the vast majority of them pass completely throughthe Earth without interacting.

NotrinoH t ch y u c cho l c t o ra t ph n ng h t nhn v i quy m l n trong cc

ngi sao; chng r t kh pht hi n v ph n l n cc h t ny i xuyn qua c c tri t m

khng c m t s t ng tc no.

Neutron Stara compressed core of an exploded st ar made up almost entirely of neutrons. Neutron starshave a strong gravitational field and some emit pulses of energy along their axis. These areknown as pulsars.

Sao notronM t nhn b nn c a m t ngi sao c c u t o g n nh hon ton l notron. Sao notron

c m t tr ng tr ng m nh v pht ra nh ng xung n ng l ng qua tr c c a chng. Chng cn

c bi t t i nh sao pulsar.

Neutronan electrically neutral elementary particle. A neutron is 1839 times heavier than an electron.

NotronM t lo i trung ha v i n tch. M t notron n ng h n electron 1839 l n.


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Newton's First Law of Motiona body continues in its state of constant velocity (which may be zero) unless it is acted uponby an external force.

nh lu t 1 Newton v Chuy n ngM t v t th s gi nguyn v n t c c a n (c th b ng khng) ch tr khi chu tc ng

c a m t ngo i l c.

Newton's Second Law of Motionfor an unbalanced force acting on a body, the acceleration produced is proportional to theforce impressed; the constant of proport ionality is the inertial mass of the body.

nh lu t 2 Newton v Chuy n ngKhi c m t l c tc ng ln v t, gia t c oc sinh ra s t l v i l n c a l c tc

ng; t l khng i b ng kh i l ng c a v t.

Newton's Third Law of Motionin a system where no external forces are present, every action force is always opposed by anequal and opposite reaction.

nh lu t 3 Newton v Chuy n ngTrong m t h khng c ngo i l c, m i l c tc ng u c ph n l c cng ph ng

ng c chi u cng l n.

Nodule

a semi-spherical fragment of rock embedded in a matrix with a different composition.NoduleM t m u d ng bn c u c bao b i m t m ng l i c thnh ph n khc nhau.

Novaa star that flares up to several times its original brightness for so me time before returning to itsoriginal state.

Sao m iM t ngi sao to sng v i sng g p vi l n bnh th ng m t th i gian tr c khi tr

l i tr ng thi ban u c a mnh.

Nuclear Fusiona nuclear process whereby several small nuclei are combined to make a larger one whosemass is slightly smaller than the sum of the small ones. The difference in mass is converted toenergy by Einstein's famous equivalence E=mc2. Nuclear fusion is the reaction that fuels theSun, where hydrogen nuclei are fused to form helium.


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Ph n ng nhi t h chM t qu trnh c a h t nhn m vi h t nhn nh k t h p v i nhau t o ra h t

nhn l n h n v i kh i lu ng nh h n m t t t ng kh i l ng hai h t nhn c . Kh i l ngchnh l ch ny c chuy n thnh nng l ng trong ph ng trnh n i ti ng c a EinsteinE=mc^2. Ph n ng nhi t h ch l ph n ng c trong M t Tr i, t i h t nhn nguyn t hydrok t h p t o thnh heli.

Nucleusthe positively charged core of an atom, consisting of protons and neutrons (except forhydrogen), around which electrons orbit.

H t nhnNhn c a m t nguyn t , g m cc proton v neutron (tr hydro), quay quanh l cc

electron.

OOblatenessa measure of flattening at the poles of a planet or other celestial body.

d tTh c o b t t i hai c c c a m t hnh tinh hay cc thin th khc.

Obliquity

the angle between a body's equatorial plane and orbital plane. nghingGc gi a m t ph ng xch o c a m t thin th v m t ph ng qu o c a n.

Occultationthe blockage of light by the intervention of another object; a planet can occult (block) the lightfrom a distant star

Che khu t

S che khu t nh sng b i m t thin th khc; m t hnh tinh c th che nh sng tm t ngi sao xa.

Olda planetary surface that has been modified little since its formation typically featuring largenumbers of impact craters; (compare to young).


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GiB m t c a m t hnh tinh t b thay i k t khi n c hnh thnh m i n hnh l

c m t l ng l n cc h thin th ch ( i l p v i tr ).

Oort Clouda theoretical shell of comets that is believed to exist at the outermost regions of our SolarSystem. The Oort cloud was named after the Dutch astronome r who first proposed it.

m my OortM t l p v cc sao ch i c tin r ng t n t i bn ngoi cng c a h m t tr i. m

my Oort c t theo tn c a m t nh thin vn h c ng i H Lan l ng i u tin xu t ra n.

Open Clustera collection of young stars that formed together. They may or may not be still bound bygravity. Some of the youngest open clusters are still embedded in the gas and dust from which

they formed.C m sao mM t nhm cc ngi sao tr c hnh thnh cng lc. Chng c th ho c khng cn s

rng bu c tr ng l c v i nhau. M t s c m sao m tr nh t v n cn c bao b c trong kh vb i sinh ra chng.

Oppositionthe position of a planet when it is exactl y opposite the Sun as seen from Earth. A planet atopposition is at its closest approach to the Earth and is best suitable for observing.

i l pV tr c a m t hnh tinh khi n i di n chnh xc v i M t Tr i khi nhn t Tri t. M t

hnh tinh t i v tr i l p c ng ang v tr g n Tri t nh t v l v tr thch h p quanst.

Orbitthe path of an object that is moving around a second object or point.

Qu oCon ng c a m t th n th di chuy n xung quanh m t thin th khc hay m t i m

no .

Orbital Periodthe amount of time it takes a spacecraft or other object to travel once around it's orbit.

Chu k qu oKho ng th i gian m t con tu v tr ho c m t thin th khc i h t m t vng qu

o c a mnh.


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PPaleozoica geological term denoting the time in Earth history between 570 and 245 million years ago.

i c sinhM t thu t ng a ch t h c ch th i i m Tri t trong qu kh vo kho ng 570 t i

245 tri u nm v tr c.

Palimpsesta circular feature on the surface of dark icy moons such as Ganymede and Callisto lacking therelief associated with craters; Palimpsests are thought to be impact craters where thetopographic relief of the crater has been eliminated by slow adjustment of the icy surface.

Palimxet (dch t m: da c u n o)M t nt c tr ng trn b m t c a cc m t trng t i bng gi nh Ganymede v

Callisto thi u v ng nh ng a hnh c lin quan t i h thin th ch; cc Palimxet c cho lnh ng h thin th ch m cc mi ng h c l p y do s i u chnh ch m ch pc a b m t bng gi.

Pallasitea stony-iron meteorite in which nodules of olivine (a silicat e mineral) are surrounded by anetwork of iron-nickel metal.

PallasiteM t thin th ch -kim lo i m cc nodule c a khong olivin (m t lo i khong

silicate) c bao b c b i m t m ng l i kim lo i s t-niken.

Parallaxthe apparent change in position of two objects viewed from different locations.

Th saiS thay i v v tr c a hai thin th c quan st t cc a i m khc nhau.

Parseca large distance often used in astronomy. A parsec is equal to 3.26 light years.

ParsecM t kho ng cch l n th ng dng trong thin vn h c. M t parsec b ng 3.26 nm nh

sng.


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Paterashallow crater; scalloped, complex edge.

Hoa vn n i hnh da (dch t m)M t h thin th ch nng v i ra c hnh d ng v s ph c t p.

Peak ringa central uplift characterized by a ring of peaks rather than a single peak; peak rings aretypical of larger terrestrial craters above about 50 kilometers (30 miles) in diameter.

Vnh ai ni (dch t m)M t trung tm c p cao ln b i m t vnh ai cc nh ni ch khng ph i l m t

nh ni; cc vnh ai ni c tr ng cho cc mi ng h thin th ch l n cc hnh tinh v i ng knh kho ng 50 km (30 d m).

Penumbra

the area of partial illumination surrounding the darkest part of a shadow caused by an eclipse.Vng n a t iVng c chi u sng m t ph n xung quanh ph n t i nh t c a m t ci bng trong hi n

t ng thin th c.

Periapsisthe point in the orbit closest to the planet.

C n i m qu o

Kho ng cch g n trn qu o g n hnh tinh ang xt nh t.

Perigeethe point in the orbit of the Moon or other satellite at which it is closest to the Earth.

i m c n aV tr trn qu o c a M t Trng hay cc v tinh nhn t o m n g n tri t

nh t.

Perihelionthe point in the orbit of a planet or other body where it is closest to the Sun.

i m c n nh tV tr trn qu o c a m t hnh tinh hay cc thin th khc m n g n M t Tr i

nh t.

Perturb


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to cause a planet or satellite to deviate from a theoretically regular orbital motion.

Lm xo tr n (dch t m) lm cho m t hnh tinh hay v tinh l ch ra kh i qu o c tnh ton theo l

thuy t.

Phasethe apparent change in shape of the Moon and inferior planets as seen from Earth as theymove in their orbits.

Tu n trngS thay i hnh dng c a M t Trng v cc hnh tinh bn trong khi nhn t Tri t

lc chng chuy n ng trn qu o c a mnh.

Planeta spherical ball of rock and/or gas that orbits a star. The Earth is a planet. Our solar system

has eight planets. These planets are, in order of increasing average distance from the Sun:Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Hnh tinhM t qu c u b ng v/hay kh quay quanh m t ngi sao. Tri t l m t hnh tinh.

H m t tr i c a chng ta c tm hnh tinh. Nh ng hnh tinh ny c s p x p theo xac a chng so v i M t Tr i: Sao Th y, Sao Kim, Tri t, Sao H a, Sao M c, Sao Th , SaoThin V ng v Sao H i V ng.

Planetesimal

a rocky and/or icy body, a few to several tens of kilometers in size, that was produ ced in thesolar nebula.

PlanetesimalM t thin th b ng v/ho c bng, m t vi trong s chng c l n kho ng m i

km, c t o ra t tinh vn m t tr i.

Precambriana geological term denoting the time in Earth history prior t o 570 million years ago.

Ti n CambriM t thu t ng a ch t h c ch th i i m Tri t vo kho ng 570 tri u nm v tr c.

Photona discrete quantity of electromagnetic energy. Short wavelength (high frequency) photonscarry more energy than long wavelength (low frequency) photons.


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PhotonM t l ng t r i r c c a nng l ng i n t . Cc photon mang b c sng ng n (t n

s cao) s mang nhi u nng l ng h n photon c b c sng di (t n s th p).

PhotosphereThe visible surface of the Sun; the upper surface of a convecting layer of gases in the outerportion of the sun whose temperature causes it to radiate light at visible wavelengths;sunspots and faculae are observed in the photosphere.

Quang quy nB m t nhn th y c a M t Tr i; b m t bn trn c a m t l p kh i l u nng ph n

ngoi c a M t Tr i m nh nhi t lm n b c x ra nh sng vng th y c; cc v ten v v t sng thu c quang quy n.

Planeta very large body in orbit around a star. Planets can be composed mainly of rock or of dense

gases.Hnh tinhM t thin th r t l n quay xung quanh m t ngi sao. Nh ungx hnh tinh c th c

c u t o ch y u t ho c kh c.

Planetary Nebulaa shell of gas surrounding a small, white star. The gas is usually illuminated by the star,producing a variety of colors and shapes.

Tinh vn hnh tinhM t l p b c kh xung quanh m t ngi sao nh , tr ng. L p kh ny th ng c chi u

sng b i ngi sao t o ra nhi u mu s c v hnh d ng.

Planitiaa low plain.

Vng t th p.

Planuma high plain or plateau.

Vng t cao ho c cao nguyn.


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Plasmaplasma consists of a gas heated to sufficiently hi gh temperatures that the atoms ionize. Theproperties of the gas are controlled by electromagnetic forces among constituent ions andelectrons, which results in a different type of behavior. Plasma is often considered the fourthstate of matter (besides solid, liquid, and gas). Most of the matter in the Universe is in theplasma state.

PlasmaPlasm g m kh c nung nng ln t i nhi t l n lm nguyn t tr thnh ion.

c tnh c a kh trn l c i u khi n b i l c i n t do t ng tc gi a cc ion v electron,k t qu lm cho chng c cc ho t ng khc th ng. Plasma th ng c coi l d ng t nt i th t c a v t ch t (bn c nh r n, l ng, v kh). H u h t v t ch t trong V Tr t n t i d ng plasma.

Precessionthe apparent shift of the celestial poles caused by a gradual wobble of the Earth's axis.

Ti n ngS dch chuy n c a thin c c do s l c l c a tr c Tri t.

Prominencean explosion of hot gas that erupts f rom the Sun's surface. Solar prominences are usuallyassociated with sunspot activity and can cause interference with communications on Earthdue to their electromagnetic effects on the atmosphere.

Bng nM t v n kh nng b m t M t Tr i. Cc v bng n trn M t Tr i th ng lin quan

t i cc ho t ng c a v t en v c th gy ra cc tc ng t i thng tin lin l c trn Tri tdo chng tc ng t i tr ng i n t trong b u kh quy n.

Proper Motionthe apparent angular motion across the sky of an object relative to the Solar System.

Chuy n ng ringGc chuy n ng t ng i v i H M t Tr i trn b u tr i c a m t thin th .

Protona positively charged elementary particle. A proton i s 1836 times heavier than an electron.

ProtonH t mang i n d ng. M t proton n ng h n electron 1836 l n.


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Protostardense regions of molecular clouds where stars are forming.

Ti n saoVng my phn t dy c hnh thnh nn cc sao.

Pseudocratera generally circular crater produced by a phreatic eruption resulting from emplacement of alava flow over wet ground.

H thng th ng hnh trn t o ra b i cc gi ng n c ng m b n ra v dung nham ch yqua cc vng t m t.

Pulsara spinning neutron star (burnt -out star) that emits energy along its gravitational axis. Thisenergy is received as pulses as the star rotates.

PulsarM t ngi sao neutron quay trn b n ra nng l ng d c theo tr c c a mnh. Nng l ng

ny c nh n nh nhp quay c a ngi sao.

Pyroclasticpertaining to clastic (broken and fragmented) rock material formed by volcanic explosion oraerial expulsion from a volcanic vent.

M nh v n ni l a

Lin quan v i cc m nh v n (b v ) c a nguyn li u , chng c t o ra b i cc vphun tro ni l a hay phun kh t mi ng phun ni l a.

Pumicea light vesicular form of volcanic glass with a high silica content; it is usually light in color andwill float on water.

b tM t lo i ch t v nh hnh c nhi u l h ng ch a m t l ng l n silic dioxit ; th ng c

mu sng v n i trong n c.


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QQuadraturea point in the orbit of a superior planet where it appears at right angles to the Sun as seenfrom Earth.

V tr gc vungi m trn qu o c a cc hnh tinh ngoi m chng t o c gc vung v i M t Tr i

khi nhn t Tri t.

QuasarAn unusually bright object found in the remote areas of the universe. Quasar s releaseincredible amounts of energy and are among the oldest and farthest objects in the knownuniverse. They may be the nuclei of ancient, active galaxies.

Quasar

M t thin th sng m t cch b t th ng c pht hi n t i cc vng cch xa chng tatrong v tr . Cc quasar gi i phng ra m t l ng nng l ng kh ng l gi a cc thin th xanh t v gi nh t c bi t t i trong v tr . Chng c th l h t nhn c a m t thin h c x aho t ng m nh.

RRadial Velocitythe movement of an object either towards or away from a stationary observer.

V n t c diChuy n ng c a m t v t th i t i hay i ra xa ng i quan st ng yn.

Radianta point in the sky from which meteors in a meteor showe r seem to originate.

i m phtM t i m trn b u tr i m c v nh cc sao bng trong m t tr n m a sao bng xu t

pht t .

Radiationenergy radiated in the form of waves or particles; photons.

B c xNng l ng pht ra d ng sng hay cc l ng t : photon.


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Radiation Belta ring-shaped region around a planet in which electrically charged particles (usually electronsand protons) are trapped. The particles follow spiral trajectories around the direction of themagnetic field of the planet. The radiation belts surrounding Earth are known as the Van Allenbelts.

Vnh ai b c xM t khu v c hnh nh chi c nh n xung quanh m t hnh tinh m cc ph n t

mang i n (thng th ng l electron v proton) b gi l i. Cc ph n t i theo ng xo n cxung quanh ng c a tr ng i n t c a hnh tinh. Cc vnh ai b c x xung quanh tri t cn c g i l cc vnh ai Van Allen.

Radio Galaxya galaxy that gives off large amounts of energy in the form of radio waves.

Thin h v tuy nM t thin h pht ra m t l ng l n nng l ng c b c sng n m trong vng v

tuy n.

Regoliththe layer of rocky debris and dust made by metoritic impact that forms the uppermost surfaceof planets, satellites and asteroids.

L p ph trn b m t v n v b i t o ra t cc v va ch m v i cc thin th t o thnhl p ph trn b m t c a cc hnh tinh, v tinh, ti u hnh tinh.

Red Gianta stage in the evolution of a star when the fuel begins to exhaust and the star expands toabout fifty times its normal size. The temperature cools, which gives the star a reddishappearance.

Kh ng l M t d ng ti n ha c a m t ngi sao khi nhin li u c a n b t u c n ki t v ngi sao

phnh to ra g p kho ng nm m i l n kch th c bnh th ng c a n. Nhi t th p i, lmcho n c mu .

Redshifta shift in the lines of an object's spectrum toward the red end. Redshift indicate s that an objectis moving away from the observer. The larger the redshift, the faster the object is moving.

Dch chuy n v M t s dch chuy n trn dy quang ph c a m t thin th v pha . Dch chuy n v

th hi n r ng thin th ang i ra xa ng i quan st. Dch chuy n v cng nhanh,thin th chuy n ng cng nhanh.


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Reflection nebulaa type of nebula that shines by reflected light. Bright stars near reflection nebulae emit lightinto the region that is reflected by the large amount of dust there. The size of the dust grainscauses blue light to be reflected more efficiently than red light, so these reflection nebulaefrequently appear blue in color.

Tinh vn ph n chi uM t lo i tinh vn sng b ng nh sng ph n chi u. Nh ng ngi sao sng g n tinh vn

ph n chi u pht nh sng t i vng v c ph n x l i nh m t l ng l n b i. Kch th cc a cc h t b i lm cho nh sng xanh c ph n chi u nhi u h n nh sng , v v u mcc tinh vn ph n chi u th ng c mu .

Retrogradethe rotation or orbital motion of an object in a clockwise direction when viewed from the northpole of the ecliptic; moving in the opposite sense from the great ma jority of solar systembodies.

Ngch hnh-i ng cChuy n ng t quay hay qu o quay c a m t thin th theo chi u kim ng h khi

nhn t c c b c c a ng hong o; chuy n ng ng c l i v i h u h t cc thin th trongh m t tr i.

Rhyolitefine-grained extrusive igneous rock, commonly with phenocrysts of quartz and feldspar in aglassy groundmass.

Khong RiolitM t lo i c b m t mn c t o ra t l a, thng th ng i cng v i phenocryst

(m t lo i ) trong th ch anh v fenspat trong m ng v nh hnh groundmass (thu t ng ikhi c s d ng ch ph n n n c a tr m tch).

Rifta fracture or crack in a planet's surface caused by extension. On some volcanoes, subsurfaceintrusions are concentrated in certain directions; this causes tension at the surface and alsomeans that there will be more eruptions in these "rift zones."

ng n tM t ch gy trn b m t c a m t hnh tinh do s dch chuy n b m t. Trong m t s ni

l a, s xm ph m ph n d i b m t t p trung t i m t s i m; i u ny gy ra p l c t i bm t v c ng ng ngha v i nhi u phun tro h n tai nh ng vng n t ny.


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Rift Valleyan elongated valley formed by the depression of a block of the planet's crust between twofaults or groups of faults of approximately parallel strike.

M t thung l ng thon di c t o ra do s ln xu ng c a m t m ng trn l p v tri tgi a hai m ng hay m t nhm cc m ng c a l p v do s dch ra g n nh song song.

Right Ascensionthe amount of time that passes between the rising of Aries and another celestial object. Rightascension is one unit of measure for locating an object in the sky.

Xch kinhKho ng th i gian gi a cung Aries (B ch D ng) m c v i cc thin th khc. Xch kinh

l m t n v o v tr c a m t thin th trn b u tr i.

Rima

a fissure.

M t v t n t.

Roche Limitthe smallest distance from a planet or other bo dy at which purely gravitational forces can holdtogether a satellite or secondary body of the same mean density as the primary. At a lesserdistance the tidal forces of the primary would break up the secondary.

Gi i h n (dch t m)Kho ng cch nh nh t t m t hnh tinh t i thin th khc m l c ht tr ng l c c

th gi m t v tinh hay m t thin th th hai hnh d ng ng nh ban u. kho ng cchnh h n, l c th y tri u c th lm v thin th th hai.

Rotationthe spin of a body about its axis.

T quayS quay c a m t thin th quanh tr c c a n.

Rupesthe term applied to scarps on planetary surfaces; many scarps are thought to be the surfaceexpression of faults within the crust of the planetary object.

RupesThu t ng c dng ch cc d c ng trn b m t m t hnh tinh; nhi u d c ng

c cho l b m t c a cc m ng c a l p v b nn l i v i nhau trn l p v c a hnh tinh.


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SSatellitea natural or artificial body in orbit around a planet.

V tinhM t thin th t nhin hay nhn t o bay xung quanh m t hnh tinh.

Semimajor axisone-half of the longest dimension of an ellipse.

Bn tr c diM t n a c a bn knh di trong hnh elip.

Seyfert Galaxya main-sequence star which rotates rapidly, causing a loss of matter to an ever -expandingshell.

Thin h SeyfertM t ngi sao dy chnh quay v i v n t c r t cao, gy ra hi n t ng m t kh i l ng v

t o ra l p v th ng xuyn m r ng.

Shield volcano

a volcano in the shape of a flattened dome, broad and low, built by flows of very fluid lava.

Ni l a hnh khinM t ni l a c d ng vm ph ng, r ng v th p, c hnh thnh do phun ra dung nham

c c l ng.

Shockunusually high pressures produced briefly by an impact. These pressures may be sufficientlyhigh to shatter, melt, and vaporize rocky material.

Gi tM t p l c cao b t th ng c t o ra trong m t kho ng th i gian ng n do m t v va

ch m. Nh ng p l c ny c th p v , nung ch y, lm b c h i cc v t li u .

Silicatea rock or mineral whose structure is dominated by bonds of silicon and oxygen atoms (ie.olivine).


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SilicatM t hn hay khong ch t m c c u thnh ch y u t nguyn t silic v oxy (v

d : khong olivin)

Siderealrelating to, or concerned with the stars. Sidereal rotation is that measured with respect to thestars rather than with respect to the Sun or the primary of a satellite.

Thin vnLin quan t i cc v sao. S quay thin vn c dng ch y u t cc v sao h n l t

M t Tr i hay cc hnh tinh.

Sidereal daythe interval of time between two consecutive transits of t he vernal equinox. More intuitively, itis the length of time required for Earth to make one full rotation with respect to the celestialsphere -- approximately four minutes shorter than the solar day.

Ngy thin vnKho ng th i gian gi a hai i m phn xun. Tr c quan h n, l kho ng th i gian

Tri t i h t m t vng khi xt trn thin c u -- n ng n h n kho ng b n l n so v i ngy Tri t.

Sidereal monththe average period of revolution of the moon around the earth in reference to a fixed star,equal to 27 days, 7 hours, 43 minutes in units of mean solar time.

Thng thin vnKho ng th i gian trung bnh m t trng quay m t vng quanh Tri t i v i m t

ngi sao c inh, b ng 27 ngy, 7 gi , 43 pht i v i th i gian m t tr i.

Sidereal periodthe period of revolution of a planet around the Sun or a satellite around its primary.

Chu k thin vnChu k quay quanh M t Tr i c a m t hnh tinh hay c a m t v tinh quanh hnh tinh

m c a chng.

Singularitythe center of a black hole, where the curvature of spacetime is maximal. At the singularity, thegravitational tides diverge. Theoretically, no solid object can survive hitting the singularity.

K dTrung tm c a m t l en, n i m khng th i gian bi u n cong c c i. T i i m k d,

l c h p d n b b cu n r i ra. Theo l thuy t, khng c m t v t th r n no c th t n t i khivo i m k d.


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Solar Cyclethe approximately 11-year quasi-periodic variation in frequency or number of solar activeevents.

Chu k M t Tr iC kho ng 11 nm l i c m t s ki n ho t ng c a M t Tr i.

Solar Flarea bright eruption of hot gas in the Sun's photosphere. Solar prominences are usually onlydetectable by specialized instruments but can be visible during a total solar eclipse.

L a M Tr iS phun tro kh nng sng trn quang quyern c a M t Tr i. Nh ng hi n t ng ny

thng th ng ch c th y b ng cc d ng c c bi t nh ng c th th y c vo lc nh tth c.

Solar Nebulathe disk of dust and gas of which the Solar System was believed to have formed about 5billion years ago.

Tinh vn M t Tr ia kh b i m H M t Tr i c cho l hnh thnh t vo kho ng 5 t nm tr c.

Solar Atmospherethe atmosphere of the Sun. An atmosphere is generally the outermost gaseous layers of aplanet, natural satellite, or star. Only bodies with a strong gravitational pull can retain an

atmosphere. Atmosphere is used to describe the outer layer of the Sun because it is relativelytransparent at visible wavelengths. Parts of the solar atmosphere include the photosphere,chromosphere, and the corona.

Kh quy n M t Tr iKh quy n c a M t Tr i. B u kh quy n th ng l l p kh xung quanh m t hnh tinh, v

tinh t nhin, hay m t ngi sao. Ch c nh ng thin th c l c h p d n m nh m i c th cb u kh quy n. B u kh quy n dng ch l p bn ngoi c a M t Tr i v n th ng lin quant i vi c pht ra cc nh sng th y c. Cc ph n c a b u kh quy n M t Tr i l quangquy n, quy n s c, v nh t hoa.

Solar Eclipsea phenomenon that occurs when the Earth passes into the shadow of the Moon. A total solareclipse occurs when the Moon is close enough to completely block the Sun's light. An annularsolar eclipse occurs when the Moon is farther away and is not able to completely block thelight. This results in a ring of light around t he Moon.


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Nh t th cHi n t ng x y ra khi Tri t i qua bng c a M t Trng. Hi n t ng nh t th c ton

ph n x y ra khi M t Trng g n che khu t hon ton nh sng M t Tr i. Hi n t ngnh t th c bn ph n x y ra khi M t Trng cn cch xa v khng th che khu t hon ton nhsng. Hi n t ng ny t o ra m t vnh sng xung quanh M t Trng.

Solar Winda flow of charged particles that travels from the Sun out into the Solar System.

Gi M t Tr iM t dng cc ph n t mang i n i t M t Tr i ra kh i H M t Tr i.

Solsticethe time of the year when the Sun appears furthest north or south of the celestial equator. Thesolstices mark the beginning of the Summer and Winter seasons .

i m ch Th i gian trong nm khi M t Tr i xu t hi n xa nh t v pha nam hay pha b c xch o b u tr i. Cc i m ch nh d u s b t u c a ma h v ma ng.

South Atlantic Anomalythe region over the South Atlant ic Ocean where the lower Van Allen belt of energetic,electrically charged particles is particularly close to the Earth's surface. The excess energy inthe particles presents a problem for satellites in orbit around the Earth.

i m g n nh t Nam i Ty D ng (dch t m)Khu v c trn vng bi n Nam i Ty D ng l n i cc ph n t mang i n m nh m

thu c vnh ai Van Allen c bi t g n b m t Tri t. S hi n di n nng l ng qu m c y t o ra m t v n cho cc v tinh nhn t o khi bay vng quanh Tri t.

Spectral Linea line in a spectrum due to the emission or absorption of electromagnetic radiation at adiscrete wavelength. Spectral lines result from discrete changes in the energy of an atom ormolecule. Different atoms or molecules can be identified by the unique sequence of spectrallines associated with them.

ng quang phM t ng trn quang ph do s pht ra hay h p th cc b c x i n t tai cc b c

sng r i r c. ng quang ph l k t qu c a cc m c nng l ng r i r c c a m t nguynt hay phn t . Cc phn t hay nguyn t khc nhau c th c nh n ra b ng cc chu i c tr ng c a chng trn ng quang ph .


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Spectrographan instrument that spreads light or other electromagnetic radiation into it's componentwavelengths (spectrum), recording the results photographically or electronically.

My ghi quang phD ng c tr i nh sng hay cc b c x i n t ra b c sng h p thnh c a n (quang

ph ), ghi l i k t qu b ng hnh nh hay i n t .

Spectrometerthe instrument connected to a telescope that separates the light signals into differentfrequencies, producing a spectrum.

Quang ph kD ng c dng k t n i v i cc knh thin vn phn chia cc tn hi u nh sng ra

cc t n s khc nhau, t o ra m t quang ph .

Spectroscopythe technique of observing the spectra of visible light from an object to determine itscomposition, temperature, density, and speed.

Quang ph h cM t ngnh quan st quang ph c a cc nh sng th y c t cc thin th tnh

ton thnh ph n, nhi t , t tr ng, v t c c a n.

Spectrumelectromagnetic radiation arranged i n order of wavelength. A rainbow is a natural spectrum of

visible light from the Sun. Spectra are often punctuated with emission or absorption lines,which can be examined to reveal the co

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