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Large, Strangely Dim Galaxy Found Lurking On Far Side of Milky Way (sciencemag.org)

Posted by BeauHD on from the lost-and-found dept.

Iwastheone shares a reprot from Science Magazine: Circling our galaxy is a stealthy giant. Astronomers have discovered a dwarf galaxy, called Antlia 2, that is one-third the size of the Milky Way itself. As big as the Large Magellanic Cloud, the galaxy's largest companion, Antlia 2 eluded detection until now because it is 10,000 times fainter. Such a strange beast challenges models of galaxy formation and dark matter, the unseen stuff that helps pull galaxies together. The galaxy was discovered with data from the European Space Agency's Gaia satellite, a space telescope measuring the motions and properties of more than 1 billion stars in and around the Milky Way. Gabriel Torrealba, an astronomy postdoc at the Academia Sinica in Taipei, decided to sift the data for RR Lyrae stars. These old stars, often found in dwarf galaxies, shine with a throbbing blue light that pulses at a rate signaling their inherent brightness, allowing researchers to pin down their distance.

Gaia data helped the team see past the foreground stars. Objects in the Milky Way's disk are close enough for Gaia to measure their parallax: a shift in their apparent position as Earth moves around the sun. More distant stars appear fixed in one spot. After removing the parallax-bearing stars, the researchers homed in on more than 100 red giant stars moving together in the constellation Antlia, they report in a paper posted to the preprint server arXiv this week. The giants mark out a sprawling companion galaxy 100 times less massive than anything of similar size, with far fewer stars.

68 comments

  1. Comment removed by account_deleted · · Score: 0, Offtopic

    Comment removed based on user account deletion

  2. But how do we know... by SqueakyMouse · · Score: 5, Funny

    Astronomers have discovered a dwarf galaxy

    How do we know it's populated by dwarves?

    1. Re:But how do we know... by Anonymous Coward · · Score: 0, Offtopic

      It's a Trump euphemism silly. Large, strangely dim.

    2. Re:But how do we know... by Freischutz · · Score: 4, Funny

      Astronomers have discovered a dwarf galaxy

      How do we know it's populated by dwarves?

      Dwarves? Don't be silly man! ... with it being so 'strangely dim' and 'luking', this is clearly the home galaxy of THE SITH!!!

    3. Re:But how do we know... by Anonymous Coward · · Score: 0

      Maybe it's an alien spacecraft!

    4. Re:But how do we know... by Anonymous Coward · · Score: 0

      Slashdot needs to patch their NPCs because their dialogue is outdated.

    5. Re:But how do we know... by Anonymous Coward · · Score: 0

      Not just any dwarves - dim dwarves.

      A whole galaxy full of stupid, small people - Amazing!

    6. Re:But how do we know... by jfdavis668 · · Score: 3, Funny

      I'm waiting until the find the elf galaxy.

    7. Re:But how do we know... by Anonymous Coward · · Score: 0

      There's a trail of empty ale barrels and kegs coming from the galaxy.

    8. Re:But how do we know... by Anonymous Coward · · Score: 0

      You really don't want to go there. Slaanesh is waiting...

    9. Re:But how do we know... by squiggleslash · · Score: 1

      They're actually more specific than that, apparently these dwarves aren't very bright. How do they know? HOW DO THEY KNOW?!

      --
      You are not alone. This is not normal. None of this is normal.
    10. Re:But how do we know... by Sunastar · · Score: 3, Funny

      To me 'strangely dim' and 'lurking' sounds more like politicians.

    11. Re:But how do we know... by aliquis · · Score: 1

      Strangely dumb and leaving black holes?

    12. Re:But how do we know... by aliquis · · Score: 1

      Considering how close they are to earthlings ..

    13. Re:But how do we know... by Anonymous Coward · · Score: 0

      'cause the Elfs told me.

      CAP === 'barging'

    14. Re:But how do we know... by Anonymous Coward · · Score: 0

      I think it should be called the Occasional-Cortex galaxy.

    15. Re:But how do we know... by Anonymous Coward · · Score: 0

      They whistle while they work.

  3. Re:Remember the murder of Ian Murdock by Anonymous Coward · · Score: 0

    +1

  4. Lurking? by Anonymous Coward · · Score: 0

    Casts ideas of nefariously hiding.

    Jeez the writing is so horrible...

  5. Re:Remember the murder of Ian Murdock by Anonymous Coward · · Score: 0

    He was a confirmed reptilian, killed off by the replicant police force.

  6. This is a clear case of... by Anonymous Coward · · Score: 0

    Aliens

    1. Re:This is a clear case of... by Anonymous Coward · · Score: 0

      You know looking into the astrophysics into inter galactic space travel, unless an alien species is capable of traveling in a higher or lower dimension, the easiest way to transcend the universe is to control the movement of a dwarf galaxy, and within that, its solar systems and planets. It is essentially a life support system crafted like even more primitive ones, but on a grander scale. We would also be talking about a species that could use stars and black holes as energy.

      Some say a planetary device would work, like the fabled Nibiru. But that would be tricky navigating interstellar space in areas that exceed 10k kelvin. A solar system would be far more resilient. But a dwarf galaxy, perfect.

  7. It needs a better name by GrumpySteen · · Score: 2, Funny

    It's large and strangely dim. We should call it "Congress."

    1. Re:It needs a better name by Anonymous Coward · · Score: 0

      It's large and strangely dim. We should call it "Congress."

      Or perhaps "Mister President", who pretty much embodies large and strangely dim.

    2. Re:It needs a better name by Anonymous Coward · · Score: 0

      Observational evidence exists for this large, strangely dim mass:

      https://www.youtube.com/watch?v=lT14-ZBPRDY

  8. Re:Strike one problem of our physics list: by Sique · · Score: 4, Informative

    Actually no. Dark Matter is not simply "missing matter" in general, it's missing matter in very well defined scenarios. A dark galaxy out there would not solve other problems which are connected to Dark Matter. It wouldn't explain the rotation of galaxies we actually see. It wouldn't explain the behavior of the gas clouds at NGC 604. It wouldn't explain the amount of light deflection we see at galaxies which bend the light of the galaxies behind them and cause us to see Einstein rings.

    --
    .sig: Sique *sigh*
  9. Re:10,000 time fainter? by Anonymous Coward · · Score: 2, Funny

    "One fainter" is a universally accepted unit of measure, equal to the brightness of a bees-wax candle placed approximately 9 and three-sixty-fourths Furlongs down the end of a dark hallway behind a frosted partition.

    Everybody knows that.

    So having a dwarf galaxy with a brightness level of 10,000 fainters is obvious not as bright a galaxy such as ours which contains roughly 97 or so fainters, depending on the eyesight of the horse.

    This isn't taught in school anymore?

  10. But it's a start by lamer01 · · Score: 0

    If it plugs the hole for one feature of the universe that is explained currently by dark matter, that is progress. We may find other things that plug the rest of the holes and then there would be no need for dark matter. Besides, wouldn't a really dim galaxy kind of 'be' dark matter since we could not see it before?

    1. Re:But it's a start by Anonymous Coward · · Score: 2, Informative

      Besides, wouldn't a really dim galaxy kind of 'be' dark matter since we could not see it before?

      If by "dim" you mean the galaxy is far far away, or has lots of dust or small stars, then no, most physicists would not say it is dark matter. Most physicists use the phrase "dark matter" to refer to a non-baryonic mass-producing phenomenon, not protons and neutrons that are poorly illuminated.

    2. Re:But it's a start by Sique · · Score: 4, Informative
      Currently, Dark Matter is the term for stuff that causes gravitational effects, but does not interact with electromagnetic fields. Ordinary matter does interact with electromagnetic fields and is often referred to as baryonic matter, but "Hubble pictures are too crisp." We can see light in pictures taken by the Hubble space telescope which has traveled more than 12 billion light years (or is more than 12 billion years old). We don't see any effects of that light to have interacted with baryonic matter during that time (e.g. slight phase differences between different frequencies, degrading sharpness or similar). Thus we can calculate an upper limit of the average amount of ordinary matter in the interstellar space. We can't account for all that baryonic matter yet, but the unaccounted for amount is shrinking, and dark galaxies like the one in the article will make the account more complete. There were other breakthroughs recently, but still, this is all baryonic (and thus ordinary and not Dark) matter.

      No, Dark Matter is not simply dark matter, matter we haven't seen yet. Dark Matter is matter we absolutely can not see, e.g. detect by its direct interactions with electromagnetic waves. We only can tell that there is Dark Matter out there because it changes Spacetime according to General Relativity. There are models where Dark Matter does interact with the Weak Force (e.g. WIMPs, Weakly Interacting Massive Particles), but so far, none of those models has been proven by an experiment or an observation.

      --
      .sig: Sique *sigh*
    3. Re:But it's a start by Anonymous Coward · · Score: 0

      > We only can tell that there is Dark Matter out there because it changes Spacetime according to General Relativity.

      I am an ignoramus, but please tell me, would it not be equally as true to say: "our maths/model does not add up at the moment, so we have invented something called dark matter, and if we can find it, then our previous maths/model will add up"?

    4. Re:But it's a start by Sique · · Score: 1
      Exactly. Any problem with that?

      Of course there are problems with that. And thus, there are many ideas floating around to come to the same results without Dark Matter. For instance, MOND (MOdified Newtonian Dynamics) is the most famous of them. TeVeS (Tensor–vector–scalar_gravity) is a relativistic generalization of MOND, Gauge vector–tensor gravity another one. The last one is very successful with one exception: It can't explain the diffusion damping necessary to have such an uniform cosmic microwave background radiation as we can see it today.

      Yes, the idea of Dark Matter is a kludge. We just don't have anything better right now. Feel free to come up with better ideas!

      --
      .sig: Sique *sigh*
    5. Re:But it's a start by painandgreed · · Score: 1

      If it plugs the hole for one feature of the universe that is explained currently by dark matter, that is progress. We may find other things that plug the rest of the holes and then there would be no need for dark matter. Besides, wouldn't a really dim galaxy kind of 'be' dark matter since we could not see it before?

      Doesn't work that way. Currently we have many holes that all lead to the same conclusion. If one got plugged but didn't plug the others also, it most likely a sign that that solution is wrong, and if it was correct, it would indicate that much weirder things than some matter than doesn't interact with the EM radiation was going on, which seems to be what most dark matter detractors are upset about. Dim galaxies are out also. Dim ordinary matter was one of the first things proposed to plug one of the holes, but tests were made and while there is an amount of undetected matter, the upper limits placed on that amount is very small to the total amount of matter that is left undetected by direct visual means.

  11. Oh boy! Now with "fluffier dark matter". by Rambo+Tribble · · Score: 2

    But will it still have that satisfying crunch?

  12. Re:10,000 time fainter? by Anonymous Coward · · Score: 0

    This isn't taught in school anymore?

    It's taught, but only in the USA.

    Elsewhere it would be stated as 100 micro-flou

  13. Thank you for spreading our excuse! -- Politicians by Anonymous Coward · · Score: 0

    As long as our livestock believes we're just oh-so dumb, we can do whatever nefarious shit we want, and the blackeyers will just dismiss it as stupidity.

    Despite the action of stupidity generally diverging due to the lack of control beyond randomness, and the actions of evilness (and goodness) converging (towards that evil/good goal). Which clearly shows us that this is not stupidity, but deliberate. Not necessarily by the politicians, and they may, and likely are, merely pawns.

  14. Re:It's not a galaxy as we know it by lgw · · Score: 2

    You joke, but a galaxy mostly covered by Dyson swarms would look something like this. It's the hardest problem in the Fermi paradox: Dyson swarms seem inevitable for a high-tech species, and would be visible in other galaxies if there were a lot of them. But we don't see that.

    --
    Socialism: a lie told by totalitarians and believed by fools.
  15. Re:It's not a galaxy as we know it by Anonymous Coward · · Score: 0

    Actually, /. installed APK for this thread ad thus APK is blocked / black-listed / turned Democrat.

    CAP === 'archly'

  16. puh-lease! by Anonymous Coward · · Score: 0

    How is it even possible for a galaxy to "lurk"?

    Has it some nefarious design?

  17. Rich with heavy elements but dim? by The+Snazster · · Score: 1

    So, with the abundance of metallicity and no central uninhabitable core or giant black hole, sentient life developed early there and now they've covered most of the good real estate over with Dyson spheres?

  18. Re:10,000 time fainter? by Anonymous Coward · · Score: 0

    I've never thought of a galaxy as "faint", so something being "fainter" doesn't really make sense to me.

    Most galaxies are so faint, you can't even see them!

    Er... does "10,000 time fainter" mean it's 1/10,000th as bright? Or put it another way "emits 1/10,000th as much light"?

    It is another way of saying its apparent manitude is 10 lower.

  19. JEALOUS "Lil' Jowie" #1/2 ZIP/Zach Patterson by Anonymous Coward · · Score: 0

    See how STUPID "ZIP" (Zach I. Patterson) CHIMP is (taking credit for what I solved before him) https://tech.slashdot.org/comm... (he needs to LEARN TO READ)!

    I even SHOW ways to do it YOURSELF https://tech.slashdot.org/comm... (he couldn't).

    Delphi/FreePascal/ObjectPascal HAS no issue w/ null-term'd string bufferoverflows - C does, C++ can UNLESS you do what I said 1st loser.

    Tell us about CODE SIGNING (which has been STOLEN & ABUSED) https://www.helpnetsecurity.co... MY METHOD CAN'T BE (upmodded +2 INTERESTING in CODING FOR DEFCON no less) https://it.slashdot.org/commen...

    "I'm a much better programmer than APK" - by Anonymous Coward ZIP on Monday October 08, 2018 @11:27PM (#57449082) FROM https://yro.slashdot.org/comme... yet nothing to show in programs. I can from registered /.ers liking/using/praising my work (& 100k users worldwide too). He can't.

    LIAR ZIP says he has no account "I don't have an account, so I don't have mod points" https://news.slashdot.org/comm...

    Yet LIAR ZIP says he downmods my posts (IMPOSSIBLE MINUS AN ACCOUNT on /.): "I down-modded a few of your post on other threads" - by Anonymous Coward "ZIP" on Thursday October 11, 2018 @11:31AM (#57461058) FROM https://yro.slashdot.org/comme...

    APK

    P.S.=> KEEP PLAYING PUSSY GAMES IMPERSONATING ME YOU CHIMP - this comes out every time, lol!... apk

  20. JEALOUS "Lil' Jowie" #2/2 c6gunner by Anonymous Coward · · Score: 0

    c6gunner CAUGHT impersonating me (his name's the submitter signing "APK") https://linux.slashdot.org/com... & you ALTERED /.ers PRAISE of my work (not yours you don't even HAVE).

    * ALL because he tried to INSULT me 2 posts parent prior to it & in the one before it I merely asked to PROVE he did better - he cannot (don't throw stones if you live in a GLASS HOUSE chump & RESPECT YOUR BETTERS (me)).

    APK

    P.S.=> KEEP PLAYING PUSSY GAMES IMPERSONATING ME YOU CHIMP - this comes out every time, lol!... apk

  21. JEALOUS "Lil' Jowie" #1/2 ZIP/Zach Patterson by Anonymous Coward · · Score: 0

    See how STUPID "ZIP" (Zach I. Patterson) CHIMP is (taking credit for what I solved before him) https://tech.slashdot.org/comm... (he needs to LEARN TO READ)!

    I even SHOW ways to do it YOURSELF https://tech.slashdot.org/comm... (he couldn't).

    Delphi/FreePascal/ObjectPascal HAS no issue w/ null-term'd string bufferoverflows - C does, C++ can UNLESS you do what I said 1st loser.

    Tell us about CODE SIGNING (which has been STOLEN & ABUSED) https://www.helpnetsecurity.co... MY METHOD CAN'T BE (upmodded +2 INTERESTING in CODING FOR DEFCON no less) https://it.slashdot.org/commen...

    "I'm a much better programmer than APK" - by Anonymous Coward ZIP on Monday October 08, 2018 @11:27PM (#57449082) FROM https://yro.slashdot.org/comme... yet nothing to show in programs. I can from registered /.ers liking/using/praising my work (& 100k users worldwide too). He can't.

    LIAR ZIP says he has no account "I don't have an account, so I don't have mod points" https://news.slashdot.org/comm...

    Yet LIAR ZIP says he downmods my posts (IMPOSSIBLE MINUS AN ACCOUNT on /.): "I down-modded a few of your post on other threads" - by Anonymous Coward "ZIP" on Thursday October 11, 2018 @11:31AM (#57461058) FROM https://yro.slashdot.org/comme...

    APK

    P.S.=> KEEP PLAYING PUSSY GAMES IMPERSONATING ME YOU CHIMP - this comes out every time, lol!... apk

  22. JEALOUS "Lil' Jowie" #2/2 c6gunner by Anonymous Coward · · Score: 0

    c6gunner CAUGHT impersonating me (his name's the submitter signing "APK") https://linux.slashdot.org/com... & you ALTERED /.ers PRAISE of my work (not yours you don't even HAVE).

    * ALL because he tried to INSULT me 2 posts parent prior to it & in the one before it I merely asked to PROVE he did better - he cannot (don't throw stones if you live in a GLASS HOUSE chump & RESPECT YOUR BETTERS (me)).

    APK

    P.S.=> KEEP PLAYING PUSSY GAMES IMPERSONATING ME YOU CHIMP - this comes out every time, lol!... apk

  23. Re:It's not a galaxy as we know it by should_be_linear · · Score: 1

    SIG: "Socialism: a lie told by totalitarians and believed by fools". So, I guess all those Dyson spheres are rented by some intergalactic real estate agency, according to you?

    --
    839*929
  24. Re:It's not a galaxy as we know it by lgw · · Score: 1

    Not sure what connection you're making. The only central authority needed for a Dyson swarm is traffic control (which is a big deal). The swarm itself is a zillion large objects orbiting the Sun, each of which can be doing its own thing - no need to assume any specific economic system, or even any uniformity of such. None, some, or all could be rented: aliens, who knows?

    --
    Socialism: a lie told by totalitarians and believed by fools.
  25. Re:It's not a galaxy as we know it by Gavagai80 · · Score: 1

    Ever more destructive extreme power consumption and environmental destruction is probably not a habit that leads a species to surviving long. Any species advanced enough to contemplate a dyson sphere could not have gotten to that point by being the kind of species that would build one.

    --
    This space intentionally left blank
  26. A giant dwarf?? by Anonymous Coward · · Score: 0

    > Circling our galaxy is a stealthy giant. Astronomers have discovered a dwarf...

  27. Easy if you know your log by Anonymous Coward · · Score: 0

    If you have trouble with this, then you probably have trouble with other power factors like MMS (Richter scale), Decibel, and Apparent magnitude.

    For example in audio, 1/10,000th as loud would mean a difference of 40 dB.

    If you're Hubble telescope can detect objects down to 34 m (apparent magnitude), but there is a galaxy at 39 m, you won't see it because it emits 1/10,000th as much light as the faintest thing you can normally see.

    ZIP

  28. Re:It's not a galaxy as we know it by lgw · · Score: 1

    The problem with all such objections is "what, every alien?" All it takes is one faction from one alien species and the galaxy would be covered with Dyson swarms. Presumably alien psychology is no less diverse than humans.

    Also, the technology needed to build a Dyson swarm isn't far ahead of what we have now. It's really the scale that makes it impressive, but it's all pretty straightforward. You really only need fusion power, and not even that to get started. We could put a hole in an asteroid and make a colony for a million people with current tech if we thought it was worth the price.

    Also, the sun won't mind if we take some of its mass one day - it will make the sun live longer, cleanse its body of toxins.

    --
    Socialism: a lie told by totalitarians and believed by fools.