andromeda and milky way might collide sooner than we think

8/20/2019 Andromeda and Milky Way Might Collide Sooner Than We Think.

1/10

22/11/2015 Andromeda and Milky Way Might Collide Sooner Than We Think

http://www.universetoday.com/120329/andromeda-and-milky-way-might-collide-sooner-than-we-think/

Universe Today

Space and astronomy news

≡ Menu

Home

MembersGuide to Space

Carnival

Photos

Videos

Forum

Contact

Privacy

Andromeda and Milky Way Might Collide Sooner Than We

Think

by Bob King on May 15, 2015

Andromeda’s halo is gargantuan. Extending for at least 2 million light years, if we could see in our night sky it would be 100 times the diameter of the Moon or 50 degrees across! Credit: NASA

The merger of the Milky Way and Andromeda galaxy won’t happen for another 4 billion years, but the recent discovery of a massive halo of hot

gas around Andromeda may mean our galaxies are already touching. University of Notre Dame astrophysicist Nicholas Lehner led a team of

scientists using the Hubble Space Telescope to identify an enormous halo of hot, ionized gas at least 2 million light years in diameter surrounding

the galaxy.

The Andromeda Galaxy is the largest member of a ragtag collection of some 54 galaxies, including the Milky Way, called the Local Group. With

a trillion stars — twice as many as the Milky Way — it shines 25% brighter and can easily be seen with the naked eye from suburban and rural

skies.

http://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Quasars-hubble.jpghttp://en.wikipedia.org/wiki/Local_Grouphttp://en.wikipedia.org/wiki/Andromeda_Galaxyhttp://www.nasa.gov/mission_pages/hubble/main/index.htmlhttp://physics.nd.edu/people/faculty/nicolas-lehner/http://www.universetoday.com/95557/its-inevitable-milky-way-andromeda-galaxy-heading-for-collision/http://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-NASA-Moon-comparison.jpghttp://www.universetoday.com/28582/privacy-policy/http://www.universetoday.com/248/contact-me/http://cosmoquest.org/forum/https://www.youtube.com/user/universetodayhttps://www.flickr.com/groups/universetodayhttp://www.universetoday.com/12019/carnival-of-space/http://www.universetoday.com/13860/guide-to-space/http://www.patreon.com/universetodayhttp://www.universetoday.com/http://www.universetoday.com/http://www.universetoday.com/


2/10


http://www.universetoday.com/120329/andromeda-and-milky-way-might-collide-sooner-than-we-think/ 2

Six examples of quasars photographed with the Hubble. Quasars are distant, brilliant sources of

light, believed to occur when a massive black hole in the center of a galaxy feeds on gas and stars.

As the black hole consumes the material, it emits intense radiation, which is then detected as a

quasar. Lehner and team measured Andromeda’s halo by studying how its gas affected the lightfrom 18 different quasars. Credit: NASA/ESA

Think about this for a moment. If the halo extends at least a million light years in our direction, our two galaxies are MUCH closer to touching that

previously thought. Granted, we’re only talking halo interactions at first, but the two may be mingling molecules even now if our galaxy is similarly

cocooned.

Lehner describes halos as the “gaseous atmospheres of galaxies”. Despite its enormous size, Andromeda’s nimbus is virtually invisible. To find and

study the halo, the team sought out quasars, distant star-like objects that radiate tremendous amounts of energy as matter funnels into the

supermassive black holes in their cores. The brightest quasar, 3C273 in Virgo, can be seen in a 6-inch telescope! Their brilliant, pinpoint nature

make them perfect probes.

To detect Andromeda’s halo, Lehner and team studied how the light of 18 quasars (five shown

here) was absorbed by the galaxy’s gas. Credit: NASA

http://i0.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda-halo-hubble-nasa.jpghttp://i1.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Quasars-hubble.jpg


3/10



by Taboola Promoted Links

“As the light from the quasars travels toward Hubble, the halo’s gas will absorb some of that light and make the quasar appear a little darker in just a

very small wavelength range,” said J. Christopher Howk , associate professor of physics at Notre Dame and co-investigator. “By measuring the dip

in brightness, we can tell how much halo gas from M31 there is between us and that quasar.”

Astronomers have observed halos around 44 other galaxies but never one as massive as Andromeda where so many quasars are available to clearly

define its extent. The previous 44 were all extremely distant galaxies, with only a single quasar or data point to determine halo size and structure.

Andromeda’s close and huge with lots of quasars peppering its periphery. The team drew from about five years’ worth of observations of archived

Hubble data to find many of the 18 objects needed for a good sample.

This illustration shows a stage in the predicted merger between our Milky Way galaxy and the

neighboring Andromeda galaxy, as it will unfold over the next several billion years. In this image,

representing Earth’s night sky in 3.75 billion years, Andromeda (left) fills the field of view and

begins to distort the Milky Way with tidal pull. Credit: NASA; ESA; Z. Levay and R. van der

Marel, STScI; T. Hallas; and A. Mellinger

The halo is estimated to contain half the mass of the stars in the Andromeda galaxy itself, in the form of a hot, diffuse gas. Simulations suggest that it

formed at the same time as the rest of the galaxy. Although mostly composed of ionized hydrogen — naked protons and electrons — Andromeda’s

aura is also rich in heavier elements, probably supplied by supernovae. They erupt within the visible galaxy and violently blow good stuff like iron,

silicon, oxygen and other familiar elements far into space. Over Andromeda’s lifetime, nearly half of all the heavy elements made by its stars have

been expelled far beyond the galaxy’s 200,000-light-year-diameter stellar disk.

You might wonder if galactic halos might account for some or much of the still-mysterious dark matter. Probably not. While dark matter still makes

up the bulk of the solid material in the universe, astronomers have been trying to account for the lack of visible matter in galaxies as well. Halos now

seem a likely contributor.

The next clear night you look up to spy Andromeda, know this: It’s closer than you think!

For more on the topic, here are links to Lehner’s paper in the Astrophysical Journal and the Hubble release.

About Bob King

I'm a long-time amateur astronomer and member of the American Association of Variable Star Observers (AAVSO). My

observing passions include everything from auroras to Z Cam stars. Every day the universe offers up something both beautiful and

From The Web More from Universe Today

A Sta r Pa ssed Th ro ugh th e Solar Sys tem Jus t 70 ,000 Yea r

…

Earth’s Second Moon is About to Leave Us

Ar e Th er e Pl anets Aroun d A lpha Centa uri?

Wh at i s th e Biggest Sta r in th e Universe?

Black Hole on Earth

http://www.universetoday.com/38434/black-hole-on-earth/http://www.universetoday.com/13507/what-is-the-biggest-star-in-the-universe/http://www.universetoday.com/13123/if-alpha-centauri-has-earth-like-planets-we-can-detect-them/http://www.universetoday.com/32/earths-second-moon-is-about-to-leave-us/http://www.universetoday.com/119038/a-star-passed-through-the-solar-system-just-70000-years-ago/http://www.universetoday.com/author/bob-king/http://hubblesite.org/newscenter/archive/releases/2015/15/full/http://iopscience.iop.org/0004-637X/804/2/79/pdf/0004-637X_804_2_79.pdfhttp://www.universetoday.com/61587/dark-matter/http://i0.wp.com/www.universetoday.com/wp-content/uploads/2015/05/Andromeda_Collides_Milky_Way.jpghttp://popup.taboola.com/en/?template=colorbox&taboola_utm_source=universetoday&taboola_utm_medium=bytaboola&taboola_utm_content=hybrid-text-links-a:Below%20Article%20Text%20Links:http://popup.taboola.com/en/?template=colorbox&taboola_utm_source=universetoday&taboola_utm_medium=bytaboola&taboola_utm_content=hybrid-text-links-a:Below%20Article%20Text%20Links:http://popup.taboola.com/en/?template=colorbox&taboola_utm_source=universetoday&taboola_utm_medium=bytaboola&taboola_utm_content=hybrid-text-links-a:Below%20Article%20Text%20Links:


4/10



Tweet 1.4k 1 point

- . .

Share this:

@astrobob_bk

Comments on this entry are closed.

Dilgin May 15, 2015, 4:09 PM

until I looked at the draft of $7949 , I didnt believe that…my… neighbour was truley earning money part time on their laptop. . there uncle

started doing this 4 less than twenty months and a short time ago cleared the mortgage on their villa and purchased a top of the range BMW .

Get More Info……………………………http://2.gp/GbUf

Link

Ponce May 16, 2015, 12:48 AM

Go join your neighbor and their Uncle while we discuss the subject in this article @dilgin.

Link

altizar May 15, 2015, 5:36 PM

“You might wonder if galactic halos might account for some or much of the still-mysterious dark matter. Probably not.”

Actually probably so. It’s not just the amount of matter, but also the distance from the center. Dark matter is based on rotational speed. If the

objects are larger than we think they are, they’re going to spin faster than they look like they should. Plus we underestimated the size of our

own galaxy by 60%. Another strike against dark matter since we use our own galaxy as a baseline to estimate other galaxies.

Link

Email Print 1.4kShare 49 Share 12

Related

http://www.universetoday.com/120329/andromeda-and-milky-way-might-collide-sooner-than-we-think/?share=email&nb=1http://www.astrobob.areavoices.com/http://-/?-http://-/?-http://-/?-http://2.gp/GbUfhttps://twitter.com/astrobob_bkhttp://www.reddit.com/r/SpaceNewsBot/comments/3633s9/andromeda_and_milky_way_might_collide_sooner_than/http://www.reddit.com/r/SpaceNewsBot/comments/3633s9/andromeda_and_milky_way_might_collide_sooner_than/http://www.reddit.com/r/SpaceNewsBot/comments/3633s9/andromeda_and_milky_way_might_collide_sooner_than/http://www.reddit.com/r/SpaceNewsBot/comments/3633s9/andromeda_and_milky_way_might_collide_sooner_than/http://www.tumblr.com/share/link/?url=http%3A%2F%2Fwww.universetoday.com%2F120329%2Fandromeda-and-milky-way-might-collide-sooner-than-we-think%2F&name=Andromeda%20and%20Milky%20Way%20Might%20Collide%20Sooner%20Than%20We%20Thinkhttps://twitter.com/intent/tweet?original_referer=http%3A%2F%2Fwww.universetoday.com%2F120329%2Fandromeda-and-milky-way-might-collide-sooner-than-we-think%2F&ref_src=twsrc%5Etfw&text=Andromeda%20and%20Milky%20Way%20Might%20Collide%20Sooner%20Than%20We%20Think%3A&tw_p=tweetbutton&url=http%3A%2F%2Fwww.universetoday.com%2F120329%2Fandromeda-and-milky-way-might-collide-sooner-than-we-think%2F&via=universetoday


5/10



Bob King May 15, 2015, 5:44 PM

Alizarin,

I’m referring only to visible matter in galactic halos. This material is not sufficient to account for dark matter’s overwhelming presence.

Link

altizar May 15, 2015, 6:02 PM

I’ll agree that halos by themselves don’t account for enough matter to disallow for dark matter.

However, since dark matter was introduced as a possible explanation I’ve never accepted it. Just on the basis of the fact that

you want me to believe that there’s an invisible substance so abundant in this universe that it should account for 90% of all

matter, yet we can’t detect it, in any fashion except by supposed evidence of its gravity effect. Make a statement like that in any

other field of science, and you’ll get the return answer that there’s obviously something wrong with your baseline assumptions

that are being made.

Link


altizar,

While it sounds fantastic, the best minds out there not only have shown that there is dark matter – and lots of it – but that

it has to exist for galaxies to have formed and gathered into clusters in the first place.

Link

usnmcb10 May 15, 2015, 7:14 PM

Where from my location in Florida (27d 2′ 38″ N – 82d 14′ 10″ W) would I look in the night sky to see Andromeda?

Link


usnmcb10,

The Andromeda Galaxy is about 20 degrees high in the northeastern sky below and to the right of the W of Cassiopeia just before the

start of morning twilight, so around 3:45 a.m. or so. Not a convenient hour but still definitely visible from your location if you know

where to look.

Link

TerryG May 15, 2015, 10:06 PM

“Andromeda’s aura is also rich in heavier elements, probably supplied by supernovae.”

Supernova nucleosynthesis certainly contributes to the observed metal populations. Is this the only source? For example, might not

nucleosynthesis via relativistic jets colliding with the inter-stellar medium around a galaxy also add to the observed metal populations in

http://whitelinefever.com/forum/RugbyLeagueGrandstand/http://whitelinefever.com/forum/RugbyLeagueGrandstand/http://-/?-http://www.astrobob.areavoices.com/http://www.astrobob.areavoices.com/http://-/?-http://-/?-http://www.astrobob.areavoices.com/http://www.astrobob.areavoices.com/http://-/?-http://-/?-http://www.astrobob.areavoices.com/http://www.astrobob.areavoices.com/


6/10



Andromeda’s aura?

Link

Bob King May 15, 2015, 11:18 PM

TerryG,

I suppose in some galaxies they may contribute to nucleosynthesis, but I’m not aware of large relativistic jets in Andromeda similar to

say, M87. I wonder too whether material cast off by red giants as they evolve into white dwarfs might not also make a contribution to

heavy elements in the interstellar medium that might ultimately get blown into the halo.

Link

UFOsMOTHER May 15, 2015, 10:36 PM

Bob there are Many other great minds on this Earth that do Not Believe in Dark Matter I believe that all the (so called) Missing Mass is

inside all the Massive Black holes in the centre of all the Galaxies and we are almost ready to Prove this once and for all…Amen

Link

TerryG May 15, 2015, 10:59 PM

Adding hidden mass to the inside of a galaxy would exacerbate the Galaxy rotation curves issues that are solved by the prediction of

Dark Matter residing in an outer galactic halo.

It’s fine to have a new theory, so long as it out-perform the current theory.

[img]http://upload.wikimedia.org/wikipedia/commons/thumb/e/ec/M33_rotation_curve_HI.gif/630px-

M33_rotation_curve_HI.gif[/img]

Rotation curve of a typical spiral galaxy: predicted (A) and observed (B). Dark matter can explain the ‘flat’ appearance of the velocitycurve out to a large radius.

Link

UFOsMOTHER May 16, 2015, 7:49 AM

TerryG , Think about this when a Super Super Super Black Hole eats away All its surrounding Galaxy there is only a Black

Hole left therefore you cant see it and these hidden Black Holes distributed (Between known Galaxies) Stabalise the Known

Cosmos so there is (NO NEED FOR DARK MATTER) but I may be the only one that knows or believes this and until

proven otherwise is as valid as the rest of the guesswork out there

Link

Bob King May 15, 2015, 11:21 PM

UFOs,

I’m sure you’re correct that there are. I’m trying to present what for now is the best if imperfect explanation for all the extra mass we

see. Even Fritz Zwicky considered “dark matter” a possibility as long ago as the 1930s. I agree that it’s unsatisfying, but that’s only

because we’re at the cusp of understanding its nature.

http://www.astrobob.areavoices.com/http://www.astrobob.areavoices.com/http://-/?-http://-/?-http://en.wikipedia.org/wiki/Galaxy_rotation_curvehttp://whitelinefever.com/forum/RugbyLeagueGrandstand/http://whitelinefever.com/forum/RugbyLeagueGrandstand/http://-/?-http://-/?-http://www.astrobob.areavoices.com/http://www.astrobob.areavoices.com/http://-/?-


7/10



Link

TedH May 16, 2015, 11:06 AM

I believe in “Dark Matter”. The numbers show us there is “something” out there creating the effects we see / observe. Ok, I also don’t

like the fact not knowing WHAT creates these effects… not being able to “see them”, explore them but… for starters we gave it a

name: “Dark Matter” and, even more weirder… “Dark Energy”. The child has a name despite the fact we know nothing about it but

it’s presence / being out there…. somewhere… Hallo…. haaaaallooooooo???

Link

Ponce May 16, 2015, 12:56 AM

Space has enough space for all matter- seen or unseen. Much has been learned and proven true. You may note that wha man has gleened is

just scratching the surface of Universal knowledge.

Unseen matter is known to exist but remains unexplainable despite the effects it has on visible matter.

Space dust, like fog, reflects light to the point it distorts the source. Much of what is considered “Fact” may turn out to be what is

unexpected.

Nevertheless, the more we learn, the better it gets.

Link

romeo May 16, 2015, 4:56 PM

I have a querie. If the BIG CHILL theory is corect, how come Andromeda and Milky Way are on a collision course ? They should run away

one from each other. So this thing (the merge of the galaxyies) has to contradict the big chill theory.

Link


Romeo,

Good question. The reason they don’t run away from each other is that within the Local Group (which is small scale stuff compared to

the scale of superclusters) individual galaxies have their own motions. The Local Group is a subunit of the Virgo Supercluster and even

larger Laniakea Supercluster that do participate in the overall expansion of the universe.

Link

Olaf May 17, 2015, 2:38 PM

When they are close enough then gravitational forces are bigger then the dark energy expanding forces the objects still gets pulled

towards each other.

There will be a certain distance from an object where the expanding force equals the gravitational force. Any further than that then the

expanding forces are bigger than the gravitational forces.

Link

http://-/?-http://-/?-http://www.astrobob.areavoices.com/http://www.astrobob.areavoices.com/http://-/?-http://-/?-http://-/?-http://www.heubach.org/http://www.heubach.org/http://-/?-


8/10



UFOsMOTHER May 16, 2015, 5:40 PM

Bob King always gives us Great things to think about and some of the Best Photos I have seen of the Cosmos taken from the ground around

his House and around the USA, We all know and appreciate the effort and for Bobs hard work and I know many of your readers thoroughly

enjoy and look forward to your next topic. Thanks Again Bob your a true Star

Link


UFOs,

You’re much too nice. Thank you!

Link

Mich48 May 17, 2015, 11:47 PM

Why can’t dark matter just be space dust. It is matter and dark and no one would say that doesn’t exist. I don’t believe in some new exotic

substance that we can’t detect. Also, when Andromeda does fling by maybe we can have a new world that we can hop on before our sun

does us in.

Link

Bob King May 18, 2015, 9:05 AM

Mich48,

I used to wonder the same, but astronomers have accounted for that plus black holes, white dwarfs, brown dwarfs and all kinds of

other things made of normal matter. They still don’t add up to anywhere near the amount of mass to account for the rotation curves of

galaxies. The current theory of galaxy cluster formation is also based on dark matter serving as “seeding sites” for their formation, too.

It seems we can’t escape it … at least for now.

Link

Next post:Weekly Space Hangout – May 15, 2015: Finding, Studying and Visiting Other Worlds!

Previous post: Carnival of Space #405

Search

Follow us

Facebook

Twitter

LinkedIn

Google Follow

YouTube

Pinterest

http://instagram.com/universetodayhttp://www.pinterest.com/universetodayhttp://www.youtube.com/user/universetoday?sub_confirmation=1https://plus.google.com/+universetodayhttp://www.linkedin.com/in/universe-todayhttp://twitter.com/intent/follow?source=followbutton&variant=1.0&screen_name=universetodayhttp://www.facebook.com/universetodayhttp://www.universetoday.com/120334/carnival-of-space-405/http://www.universetoday.com/120331/weekly-space-hangout-may-15-2015-finding-studying-and-visiting-other-worlds/http://-/?-http://www.astrobob.areavoices.com/http://www.astrobob.areavoices.com/http://-/?-http://-/?-http://www.astrobob.areavoices.com/http://www.astrobob.areavoices.com/http://-/?-


9/10



It's Finally Here! Comet Catalina Greets Dawn Skywatchers

Zodiac Signs and Their Dates

How Can You See a Satellite View of Your House?

See Daytime Views of Pluto and Charon's Rotation

NASA Orders First Commercial Crew Mission to Space Station from SpaceX

Who Discovered Electricity?

How Long Does it Take to get to the Moon?

A Universe of 10 Dimensions

What Does The Apollo 11 Moon Landing Site Look Like Today?

Order Of the Planets From The Sun

Tumblr

RSS

Phase of the Moon

November 22, 2015

Waxing gibbous

86% illuminated

363,461 km from Earth

11 days old

Get the official Universe Today Phases of the Moon app for your

iPhone or Android

Subscribe to Universe Today via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 952 other subscribers

Email Address

Subscribe

Top Posts & Pages

http://www.universetoday.com/72305/order-of-the-planets-from-the-sun/http://www.universetoday.com/113359/what-does-the-apollo-11-landing-site-look-like-today/http://www.universetoday.com/48619/a-universe-of-10-dimensions/http://www.universetoday.com/13562/how-long-does-it-take-to-get-to-the-moon/http://www.universetoday.com/82402/who-discovered-electricity/http://www.universetoday.com/123537/nasa-orders-first-commercial-crew-mission-to-space-station-from-spacex/http://www.universetoday.com/123533/see-daytime-views-of-pluto-and-charons-rotation/http://www.universetoday.com/43384/free-satellite-view-of-my-house/http://www.universetoday.com/38076/zodiac-signs-and-their-dates/http://www.universetoday.com/123511/its-finally-here-comet-catalina-greets-dawn-skywatchers/https://play.google.com/store/apps/details?id=com.universetoday.moon.phaseshttp://itunes.com/apps/phasesofthemoonhttp://www.universetoday.com/universetoday.xmlhttp://universetoday.tumblr.com/http://instagram.com/universetodayhttp://www.universetoday.com/72305/order-of-the-planets-from-the-sun/http://www.universetoday.com/113359/what-does-the-apollo-11-landing-site-look-like-today/http://www.universetoday.com/48619/a-universe-of-10-dimensions/http://www.universetoday.com/13562/how-long-does-it-take-to-get-to-the-moon/http://www.universetoday.com/82402/who-discovered-electricity/http://www.universetoday.com/123537/nasa-orders-first-commercial-crew-mission-to-space-station-from-spacex/http://www.universetoday.com/123533/see-daytime-views-of-pluto-and-charons-rotation/http://www.universetoday.com/43384/free-satellite-view-of-my-house/http://www.universetoday.com/38076/zodiac-signs-and-their-dates/http://www.universetoday.com/123511/its-finally-here-comet-catalina-greets-dawn-skywatchers/


10/10


htt // i t d /120329/ d d d ilk i ht llid th thi k/ 10

This site rocks the Classic Responsive Skin for Thesis.

WP Admin
http://www.universetoday.com/wp-admin/http://diythemes.com/http://www.universetoday.com/72305/order-of-the-planets-from-the-sun/

andromeda and milky way might collide sooner than we think

Documents