The incredibly huge size of Andromeda next to the Moon

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This is how the Great Spiral Galaxy of Andromeda would look in the sky if it were bright enough. Sadly, its light is too faint. But imagine seeing that every night. Would you get tired of it? I know I wouldn't.

Unfortunately, it's not that bright. But it's a beautiful simulation anyway, one that gives an idea—albeit a faint one—of how huge the cosmos is. Of course, it's not the only image of this kind. Here's another one featured in NASA's Astronomy Picture of the Day.

Andromeda—or M31—is larger than our Milky Way (although not as massive, if you count the dark matter in our galaxy.) It's 2.5 million light-years from us, while the Moon is only 384,400 kilometers away. Now think that a light-year is 9.5 trillion kilometers. Even with this graphic comparison, the size of M31—or anything at a galactic scale—is truly incomprehensible for the human mind.

Written By: Jesus Diaz
continue to source article at sploid.gizmodo.com

29 COMMENTS

  1. Douglas Adams:

    Space is big. You just won’t believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.

  2. Alan4discussion:

    Stick around for 3 to 5 billion years for a really close-up view when our galaxies collide!

    And the individual stars completely manage to miss each other, the distances being so vast ! Well maybe the odd collision, who knows ? Certainly I don’t !

    • In reply to #4 by Mr DArcy:

      Alan4discussion:
      Sick around for 3 to 5 billion years for a really close-up view when our galaxies collide!

      And the individual stars completely manage to miss each other, the distances being so vast ! Well maybe the odd collision, who knows ? Certainly I don’t !

      The gravitational interactions of passing stars will probably shake up a few planetary orbits and comets.

      On the up side:- star systems will be passing by each other, so any space-faring race could planet hop to systems which would otherwise be out of range in terms of time and distance: – If they did their homework properly to make the right choices!

    • In reply to #4 by Mr DArcy:

      Alan4discussion:

      Stick around for 3 to 5 billion years for a really close-up view when our galaxies collide!

      And the individual stars completely manage to miss each other, the distances being so vast ! Well maybe the odd collision, who knows ? Certainly I don’t !

      It is not certain if the galaxies will merge or how many stars or planets will collide or be thrown out into deep space – but here is an interesting 38 second animation:
      http://www.youtube.com/watch?v=j3jJqMO7jrw

    • In reply to #4 by Mr DArcy:

      Alan4discussion:

      Stick around for 3 to 5 billion years for a really close-up view when our galaxies collide!

      And the individual stars completely manage to miss each other, the distances being so vast ! Well maybe the odd collision, who knows ? Certainly I don’t !

      Well, objects of this size just don’t collide into each other. The gravitational pull would probably create some form of new trajectories. Although a really big star could possibly crash into a planet or a small star. But, with regard to the vast amount of space between the stars that is highly unlikely. It’s not like the Andromeda and the Milky way will suddenly just crash. It will be a slow process of integration. Still, we will all be dead by then so…

      • In reply to #24 by Nunbeliever:
        >

        Well, objects of this size just don’t collide into each other. The gravitational pull would probably create some form of new trajectories. Although a really big star could possibly crash into a planet or a small star. But, with regard to the vast amount of space between the stars that is highly unlikely. It’s not like the Andromeda and the Milky way will suddenly just crash. It will be a slow process of integration.

        Yes! They will swirl and mix for millions of years. There are some interesting animated presentations of this.
        I put a short one of them on a link @#13. The danger to any life-forms, is the potential for gravitational disruption of planetary and cometary orbits.

        Still, we will all be dead by then so…

        Who knows? but if humans have not exterminated themselves, and mastered space-flight and spread to other star systems, the galaxy merger could bring new solar-systems and planets into range.

  3. Aside from the visual spectacle, the real beauty for me is the fact that this whole thing is there, existing at this very moment and consisting of real, tangible objects. OK, a few parts that we see now will have disappeared and new stuff isn’t yet visible, but forget these 2.5 million light-years, forget Einstein, forget time travel. Things happen here in our world and things happen over there at the same time. For me, that’s the wonder.

    • In reply to #6 by Lonard:

      Things happen here in our world and things happen over there at the same time. For me, that’s the wonder…

      It’s even more wondrous when you take Einstein’s ideas of spacetime into account. In the same way that the Andromeda galaxy is distant in space, it is also distant in time. So there is no real equivalent to the concept of what might be happening there at the same time something is happening here. Their “now” is as different from our “now” as our locations are distant from each other.

      I hope I didn’t give anyone else besides me a headache trying to explain that. :)

  4. All right fizzlecists among you… If it all started at a single tee-tiny point and then space itself stretched everything exponentially farther apart and everything is continuing to fly apart from that starting point at ever increasing speeds, how is it possible that galaxies could collide? And don’t give me that gravity crap- you’ve already told me it’s no match for dark energy.

    • In reply to #8 by rjohn19:

      All right fizzlecists among you… If it all started at a single tee-tiny point and then space itself stretched everything exponentially farther apart and everything is continuing to fly apart from that starting point at ever increasing speeds, how is it possible that galaxies could collide? And d…

      Gravity falls off with the square of distance while space expansion is uniform everywhere (as far as we know). That means that for things that are close enough gravity wins, but beyond a distance, for a given pair of masses, they will no longer fall together faster than space is expanding between them. However, as the space expansion accelerates it is hypothesized that the “gravity wins” distance will become so small that expanding space will tear everything apart.

      • In reply to #9 by Quine:

        Gravity falls off with the square of distance while space expansion is uniform everywhere (as far as we know). That means that for things that are close enough gravity wins, but beyond a distance, for a given pair of masses, they will no longer fall together faster than space is expanding between them.

        Likewise, gas clouds form accretion disks which evolve into stars and planetary systems, while star clusters form into galaxies – with large galaxies like Andromeda and the Milkyway attracting smaller satellite galaxies to build up their size over time.

        List of Milky Way’s satellite galaxies

        The Milky Way has several smaller galaxies gravitationally bound to it, as part of the Milky Way subgroup. This subgroup is part of the local galaxy cluster, the Local Group.

        There are between 14 and 26 small galaxies confirmed to be within 420 kpc (~1.4 million light years) of the Milky Way, though not all of them are necessarily in orbit.

        Large gravitational bodies like black-holes, galaxies, stars, planets, and moons, attract smaller masses in their close locality to them.

  5. It may be worth pointing out that no galaxy would ever look in person like it does in long-exposure photographs. If you want to get an idea what Andromeda will look like in a couple billion years or so, just look up at the Milky Way today. Despite the fact that we’re embedded within it, our galaxy looks quite dim and unspectacular to the naked eye, as compared to photographs. Andromeda will look no different.

    • In reply to #10 by Thanny:

      It may be worth pointing out that no galaxy would ever look in person like it does in long-exposure photographs. If you want to get an idea what Andromeda will look like in a couple billion years or so, just look up at the Milky Way today. Despite the fact that we’re embedded within it, our galaxy looks quite dim and unspectacular to the naked eye, as compared to photographs. Andromeda will look no different.

      Unfortunately it looks like this to most urban dwellers where light pollution and air-pollution, obscure their view.

      However, in “dark-sky” areas away from artificial light pollution on clear moonless nights, the Milkyway looks like a spectacular dense band of stars going right across the sky.

  6. Does anyone here know if this could resemble the way some other animals see the sky, hypothetically? The species with better vision and sensitivity to photons? Probably few animals have the need to observe the stars, so their vision and field of view is evolved to perform other tasks. And with billions of much brighter objects than M 31, the sky might be awfully bright if even another galaxy were visible to their naked eyes. But still, a better educated speculation, anyone?

  7. From the nasa website:

    The deep Andromeda exposure also includes two bright satellite galaxies, M32 and M110 (bottom).

    Typical, we wait millennia for a galaxy and three come along at once….. I thought I’d better get this in now as I can’t be bothered to wait 4 billion years to say it, and in any case I have no idea what will happen to the satellite galaxies by then.

    • In reply to #17 by Booska:
      >

      So there is no real equivalent to the concept of what might be happening there at the same time something is happening here. Their “now” is as different from our “now” as our locations are distant from each other.

      We are seeing the Andromeda Galaxy as is was 2.5 million years ago, if there are any aliens there, it similarly takes light from us 2.5 million years to get there for them to see the Sun. There is also a slight time shift because of relativity as the galaxies move towards each other and rotate.

      Wikipedia:

      The Andromeda Galaxy /ænˈdrɒmɨdə/ is a spiral galaxy approximately 2.5 million light-years (2.4×10^19 km) from Earth[4] in the Andromeda constellation. Also known as Messier 31, M31, or NGC 224, it is often referred to as the Great Andromeda Nebula in older texts. The Andromeda Galaxy is the nearest spiral galaxy to our Milky Way galaxy, but not the closest galaxy overall. It gets its name from the area of the sky in which it appears, the constellation of Andromeda, which was named after the mythological princess Andromeda. The Andromeda Galaxy is the largest galaxy of the Local Group, which also contains the Milky Way, the Triangulum Galaxy, and about 30 other smaller galaxies. Although the largest, the Andromeda Galaxy may not be the most massive, as recent findings suggest that the Milky Way contains more dark matter and could be the most massive in the grouping.[11] The 2006 observations by the Spitzer Space Telescope revealed that M31 contains one trillion (10^12) stars:[8] at least twice the number of stars in the Milky Way galaxy, which is estimated to be 200–400 billion.[12]

      The Andromeda Galaxy is estimated to be 7.1×10^11 solar masses.[2] In comparison a 2009 study estimated that the Milky Way and M31 are about equal in mass,[13] while a 2006 study put the mass of the Milky Way at ~80% of the mass of the Andromeda Galaxy. The two galaxies are expected to collide in 3.75 billion years, eventually merging to form a giant elliptical galaxy.

      Formation and history

      According to a team of astronomers reporting in 2010, M31 was formed out of the collision of two smaller galaxies between 5 and 9 billion years ago.[37]

      A paper published in 2012[38] has outlined M31′s basic history since its birth. According to it, Andromeda was born roughly 10 billion years ago from the merger of many smaller protogalaxies, leading to a galaxy smaller than the one we see today.

      The most important event in M31′s past history was the merger mentioned above that took place 8 billion years ago. This violent collision formed most of its (metal-rich) galactic halo and extended disk and during that epoch Andromeda’s star formation would have been very high, to the point of becoming a luminous infrared galaxy for roughly 100 million years.

      M31 and the Triangulum Galaxy (M33) had a very close passage 2–4 billion years ago. This event produced high levels of star formation across the Andromeda Galaxy’s disk – even some globular clusters – and disturbed M33′s outer disk.

      • In reply to #20 by Alan4discussion:

        In reply to #17 by Booska:
        We are seeing the Andromeda Galaxy as is was 2.5 million years ago, if there are any aliens there, it similarly takes light from us 2.5 million years to get there for them to see the Sun. There is also a slight time shift because of relativity as the galaxies move towards each other and rotate.

        True, but I thought Booska was making a different point. The actual calculations for the “now” of the Andromeda galaxy compared to our “now” are a lot more complex than is usually expressed by saying the light we see is from X million years ago. When you actually try to calculate what now would correspond to the now on some planet thousands or more light years away it gets really complicated. So for example whether you are moving in a car or not has a trivial effect on the calculations. Of course by Earth standards any time displacement difference caused by an extra 60mph is so minimal it can barely be measured. But when you are considering two Nows for people separated by millions of light years those small differences have major impact. So the Now for me and someone on Alpha Centauri if I’m standing still vs. if I’m driving in a car can vary quite a bit. Brian Green goes into this in one of his books, the idea of synching up a time slice of “now” across vast differences is quite complex and counter intuitive.

  8. In reply to Booska, Alan4discussion and Red Dog,

    I’m not sure whether you truly understood what I was saying. ‘Now’ i.e. ‘this instant’ is ‘now’ everywhere in the cosmos. There is only one ‘now’, same as the fact that the cosmos is 13.8 billion years old everywhere! This whole wondrous idea of now is often obscured by the concept of relativity and talk about light-years, and how long it takes for ‘information’ to go from one place in space to another.

    • In reply to #22 by Lonard:

      In reply to Booska, Alan4discussion and Red Dog,

      …’Now’ i.e. ‘this instant’ is ‘now’ everywhere in the cosmos. There is only one ‘now’…

      But that’s just the point. “This instant” is relative, according to Einstein. “This instant” can only exist in one place at any given moment in the same way that “this spot” can only exist in one place at a time.

      To say that this instant is “now” everywhere in the universe is a fallacy. It might be a little easier to understand if, by applying the concept of spacetime, we instead say that “this spot” is here everywhere in the universe. It becomes clear that “here” cannot exist simultaneously everywhere in the universe from the point of a single observer. Likewise, when applied to time references.

      This is the wondrous thing to which I was referring.

      • In reply to #27 by Booska:

        In reply to #22 by Lonard:

        In reply to Booska, Alan4discussion and Red Dog,

        …’Now’ i.e. ‘this instant’ is ‘now’ everywhere in the cosmos. There is only one ‘now’…

        But that’s just the point. “This instant” is relative, according to Einstein. “This instant” can only exist in one place at any gi…

        No no, Booska, I’m sorry but you are being fooled by Einstein’s relativity. As far as time is concerned, you cannot make the comparison with ‘location’ the way you did. In fact I could make your comparison to support my view by stating that ‘this instant’ – let’s call it ‘this occurrence’ – can only take place once (at one spot in space). This moment is ‘now’. However, due to space and the time it takes information to travel, this moment is perceived at different moments for different observers. But that doesn’t change the fact that the occurrence took place at one point in time. You could argue about what exactly ‘an instant’ is, and to narrow it down, let’s say it is the time that it takes for one atom to affect it’s neighboring atom. But that is besides the point and, in any case, a very difficult question to answer. Another way to imagine ‘now’ (or rather a ‘local now’ on a cosmic scale) is to think of a planet in some solar system in the Andromeda galaxy with a higher civilization. One would be justified to say that the moment you were washing the dishes (your local now), some creatures out there were playing a tennis match (their local now) at the same time. Simple as that, and spacetime doesn’t come into play, because, for my statement to hold, it is not relevant to know at which moment in time you became aware of this tennis match.

  9. Many of my friends on facebook shared this picture and just could not believe it was true. I just don’t see the big deal with this picture. I mean, I thought it was a no-brainer that we can see the Andromeda galaxy with the naked eye and that it’s quite a big object in our night sky. But apparently I was wrong…

  10. All the more reason to disbelieve in god(s) that fuss over us. Why would such entities give a passing thought over such an insignificant spec when compared to the cosmos? Think of the fun you could have out there as a god.

    All the more reason to take care of this place since we are going nowhere, space is far too vast… or at least to make every effort to save our only home before we heat it beyond the tipping point. Ah, does not look good, what a shame. This may indeed be the best of times, the way we hunt oil.

  11. Amazing. I wish we could actually see this. What better refutation of human ideas about our importance or “special” place in so-called creation could there be than to be able to see a whole other galaxy with its hundreds of billions of suns on every clear night?

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