a journey trough time and space

8/8/2019 A Journey Trough Time and Space

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A journey trough time and space..



Formation of our Solar System



The Solar System



The Sun



Facts about the Sun

Physical characteristics

Mean diameter 1.392×106 km

Flattening 9×106

Surface area 6.0877×1012 km2 11,990 × Earth

Volume 1.412×1018 km3 1,300,000 × Earth

Mass 1.9891×10

30

kg 333,000 × Earth Average density 1.408×103 kg/m3

Density Center (model): 1.622×105 kg/m3

Lower photosphere: 2×104 kg/m3

Lower chromosphere: 5×106 kg/m3

Corona (avg.): 1×1012 kg/m3

Equatorial surface gravity 274.0 m/s2 27.94 g28 × Earth Escape velocity(from the surface) 617.7 km/s55 × Earth Temperature Center (modeled):

~1.57×107 KPhotosphere (effective): 5,778 KCorona: ~5×106 K

Luminosity (Lsol) 3.846×1026 W ~3.75×1028 lm~98 lm/W efficacy

Mean Intensity (Isol) 2.009×107 W·m2·sr1



Facts about Terra

Physical characteristics

Circumference at Equator 40.074 km

Circumference at Poles 40.007 km

Diameter at Equator 12.756 km

Diameter at Poles 12.714 km

Total Surface Area 510 million km^2

Land Surface Area 149 million km^2

Percentage Surface Area that is Land 29%

Percentage Surface Area that is Water 71%

Orbital Characteristics

Aphelion 152,098,232 km

Perihelion 147,098,290 km

Semi-major axis 149,598,261 km

Eccentricity 0.01671123

Orbital period 365.256363004 days

Average orbital speed 29.78 km/s107,200 km/h

Inclination 7.155° to Sun's equator

Satellites : Luna



Factors that affect Earths shape



M

odels used for representing Earth



Ellipsoidal Earth model

Ellipsoidal Earth models are required foraccurate range and bearing calculationsover long distances.

Loran-C, and GPS navigation receivers use

ellipsoidal earth models to computeposition and way point information.

Ellipsoidal models define an ellipsoid withan equatorial radius and a polar radius.

The best of these models can represent the

shape of the earth over the smoothed,averaged sea-surface to with in about onehundred meters.

An ellipsoid is defined by either thesemimajor-axis, a, and the semiminor-axis ,b, or by a and the flattening.

The flattening is the difference in lengthbetween the two axes expressed as afraction or a decimal.

The flattening, f , is:

f = (a-b)/a

Another quantity, that, like the flattening,describes the shape of a spheroid, is thesquare of the eccentricity , e2.

It is represented by:

e2 = (a2 b2 )/a2

The ellipsoidal model offers the best mathematical approximation of Earth.

It is a simple geometrical surface



Geoid

Geoid , from the Greek "Earth-shaped", is the common definition of

our world's shape.The equipotential surface of the Earth's gravity field which best fits, ina least square sense, global mean sea level.

Limitations:

It has no complete mathematical expression.Small variations in surface shape over time introduces mall errors inmeasurement.

The irregularity of the surface would necessitate a prohibitive amountof computations.

Basic computational formula:



Gravitational field of Earth



Geopotential

Geopotential is the potential of the Earth's gravity field. For convenience it is oftendefined as minus the potential energy per unit mass, so that the gravity vector isobtained as the gradient of this potential, without the minus.

For geophysical applications, gravity is distinguished from gravitation. Gravity isdefined as the resultant of gravitation and the centrifugal force caused by the Earth's

rotation.

The global mean sea surface is close to one of the equipotential surfaces of thegeopotential of gravity.

This equipotential surface, or surface of constant geopotential, is called the geoid.

For the purpose of satellite orbital mechanics, the geopotential is typically describedby a series expansion into spherical harmonics (spectral representation). In thiscontext the geopotential is taken as the potential of the gravitational field of theEarth, that is, leaving out the centrifugal potential.



Geopotential Surfaces



Geopotential Surfaces

Geopotential surf ace (equipotentialsurface)

A surface of constant geopotential is asurface along which a parcel of air couldmove without undergoing any changes inits potential energy.

Geopotential surfaces almost coincidewith surfaces of constant geometricheight. Because of the poleward increaseof the acceleration of gravity along a

surface of constant geometric height, agiven geopotential surface has a smallergeometric height over the poles thanover the equator.

Geopotential - The potential energy of aunit mass relative to sea level,numerically equal to the work that wouldbe done in lifting the unit mass from sealevel to the height at which the mass is

located; commonly expressed in terms of dynamic height or geopotential height.

The geopotential at height z is givenmathematically by the expression:

where g is the acceleration of gravity.



Dynamic height (geodynamic height)

The height of a point in the atmosphereexpressed in a unit proportional to thegeopotential at that point.

One of the practical advantages of the dynamicheight over the geometric height is that when theformer is introduced into the hydrostaticequation the height acceleration of gravity is

eliminated.

In meteorological height calculationsgeopotential height is more often used thandynamic height.

In oceanography, dynamic computations are alsobased upon units of dynamic height (or dynamic

depth).

The dynamic height is computed from themeasured density distribution.

Potential energy The energy a system has byvirtue of its position; the negative of the work

done in taking a system from a referenceconfiguration, where the potential energy isassigned the value zero, to a given configuration,with no change in kinetic energy of the system.

An example of potential energy is thegravitational potential energy of a point mass mat a distance r from the center of a sphericallysymmetric body with mass M (e.g., a planet):

where G is the universal gravitational constantand the reference potential energy is taken aszero at infinity.



Geopotential height - The height of a given point in the atmosphere in units

proportional to the potential energy of unit mass at this height relative to sea

level.

The relation, in SI units, between the geopotential height Z and the geometric

height z is

where g is the acceleration of gravity, so that the two heights are numerically

interchangeable for most meteorological purposes. Also, one geopotential

meter is equal to 0.98 dynamic meter.



Exosphere - The outermost layer of Earth's atmosphere extends

from the exobase upward.

It is mainly composed of hydrogen and helium. The particles are

so far apart that they can travel hundreds of kilometres without

colliding with one another.

Thermosphere - Temperature increases with height in the

thermosphere from the mesopause up to the thermopause,then is constant with height. The temperature of this layer can

rise to 1,500 °C (2,730 °F), though the gas molecules are so far

apart that temperature in the usual sense is not well defined.

The International Space Station orbits in this layer, between 320

and 380 km (200 and 240 mi).

The top of the thermosphere is the bottom of the exosphere,

called the exobase. Its height varies with solar activity and

ranges from about 350 800 km (220 500 mi; 1,100,000

2,600,000 ft).



Mesosphere - The mesosphere extends from the stratopause to 80 85 km(50 53 mi; 260,000 280,000 ft). It is the layer where most meteors burn upupon entering the atmosphere. Temperature decreases with height in themesosphere. The temperature minimum that marks the top of themesosphere, is the coldest place on Earth and has an average temperaturearound 85 °C (121 °F; 188.1 K).

Due to the cold temperature of the mesophere, water vapor is frozen,forming ice clouds. A type of lightning referred to as either sprites or ELVES,form many miles above thunderclouds in the troposphere.

Stratosphere - The stratosphere extends from the tropopause to about51 km (32 mi; 170,000 ft). Temperature increases with height, which restrictsturbulence and mixing.

The stratopause, which is the boundary between the stratosphere andmesosphere, typically is at 50 to 55 km (31 to 34 mi; 160,000 to 180,000 ft).The pressure here is 1/1000 sea level.

Troposphere - The troposphere begins at the surface and extends tobetween 7 km (23,000 ft) at the poles and 17 km (56,000 ft) at the equator,with some variation due to weather. The troposphere is mostly heated bytransfer of energy from the surface, so on average the lowest part of thetroposphere is warmest and temperature decreases with altitude. Thispromotes vertical mixing (hence the origin of its name in the Greek word"", t rope, meaning turn or overturn). The troposphere contains roughly80% of the mass of the atmosphere.

T

he tropopause is the boundary between the troposphere and stratosphere.



Interesting phenomena



The masterminds

Vinturici Sergiu

Muntean George Dan

iculae George Daniel

Perederic Ionut-Cristian

and our project manager

S.l.dr.ing. Irina Carmen Andrei

a journey trough time and space

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