Space, the Universe and everything

[Guest theeldergeek]

Sat pondering today, as you do, it suddenly dawned on me that I don't really understand space. I've been watching "The Wonders of the Solar System" on TV, and that has made what is going on a lot easier to understand, but what is beyond that?

 

That is, I understand our Solar System, but where does that fit into the bigger picture? I hear of the Milky Way, but I'm not entirely sure what it is. Where do we fit into "the Universe". Is the Universe one, or are there many? Are those 'swirls' you see in Hubble pictures other Universe's or part of ours? What are Galaxy's? Do Universe's fit in Galaxy's, or vice versa, or not at all? I presume our Solar System fits into a Universe or Galaxy somewhere, but where? Is our Sun the centre of a Universe, or just our Solar System?

 

I did some Googling, but I think I need something easy to follow to understand what is actually going on beyond our own Solar System 'cos it's dawned on me how much I really don't understand the subject of space.

 

Edited April 9, 2010 by theeldergeek

[SYNACK]

• Our solar system is a planetary system consisting of planets and objects orbiting a star, ours is called the solar system as the name of the sun is Sol. Others would be called planetary systems.
  
• A galaxy is a grouping of hundreds of thousands stars and planetary systems like the milky way - ours - and can be in various shapes, the milky way is a spiral arm galaxy. HubbleSite - Picture Album: Galaxies
  
• There are a huge and unknown amount of galaxies that exist inside the Universe which is the overall container and by current theories is an infinite size.
  
• There may or may not be other universes in the form of parallel universes, other dimensions etc but none of this is based on anything more than imagination and speculation.
  

 

As to the images from hubble it depends on where it was pointing, if you were to provide some example links we could pin it down though. If you were talking about shots with lots of little swirls then those were probably galaxies.

[Guest theeldergeek]

• Our solar system is a planetary system consisting of planets and objects orbiting a star, ours is called the solar system as the name of the sun is Sol. Others would be called planetary systems.
  
• A galaxy is a grouping of hundreds of thousands stars and planetary systems like the milky way - ours - and can be in various shapes, the milky way is a spiral arm galaxy. HubbleSite - Picture Album: Galaxies
  
• There are a huge and unknown amount of galaxies that exist inside the Universe which is the overall container and by current theories is an infinite size.
  
• There may or may not be other universes in the form of parallel universes, other dimensions etc but none of this is based on anything more than imagination and speculation.
  

 

As to the images from hubble it depends on where it was pointing, if you were to provide some example links we could pin it down though. If you were talking about shots with lots of little swirls then those were probably galaxies.

 

I found this A Map of the Milky Way which I think puts a Galaxy into perspective... If that highlighted point on the picture is our Sun, then our Solar System is tiny within our Galaxy. But this means we are toward the edge of our Galaxy, yes? So, other Galaxy's such as this exist, and although we can see them via telescopes and other science's, they are clearly a very, very long way away. Fascinating. I don't know why I've not pondered this subject before!

 

Why is the Milky Way talked about as if it is something we look at, rather than something we are part of?

Edited April 9, 2010 by theeldergeek

[dhicks]

I don't really understand space

 

There's, like, a lot of it. It's big. And empty. No one can hear you scream in it. Our solar system is part of the Milky Way galaxy, one of those spirally-things the Hubble telescope lets us see others of a really, really long way off. We aren't anywhere particularly near the centre of the galaxy, we're on more of a rural branch line off on one of the arms. The galaxy is part of the universe, the exact nature of which is still rather hazy, but basically seems to consist of a bunch of galaxies all expanding away from a central point (which, again, we're nowhere near). The reason they are expanding is because they were created by a big explosion, in which all matter expanded from one central point. What, exactly, was there before is a bit of a puzzle, as is what, exactly, is outside the confines of the expanding universe - the nothingness of space, or a different kind of nothingness with has nothing to do with the kind of nothingness that you're used to thinking nothing of?

 

There might be other universes floating around, or (as many scientists and many, many more science finction writers, film scripts and Star-Trek fans have speculated) they might be congruent with our own space, requiring some kind of dimension-hopping trick to get to.

 

--

David Hicks

Edited April 9, 2010 by dhicks

[dhicks]

Why is the Milky Way talked about as if it is something we look at, rather than something we are part of?

 

Because we, and our ancestors, see it as a bunch of lights in the sky at night. You don't need to know what something is to name it, you just need something you can point at and go "That's the milky way!".

 

--

David Hicks

[6Foot2]

These two links:

 

Link 1: http://uploads.ungrounded.net/525000/525347_scale_of_universe_ng.swf [You have to wait for the SWF to load]

 

Link 2: Hieght

 

Posted in this Edugeek thread: Link 3: http://www.edugeek.net/forums/links/53361-scale-universe.html

 

are both representations which try to give an idea of scale in of objects in the universe [A knowledge of how logarithmic scales work might be helpful here]

[SYNACK]

I found this A Map of the Milky Way which I think puts a Galaxy into perspective... If that highlighted point on the picture is our Sun, then our Solar System is tiny within our Galaxy. But this means we are toward the edge of our Galaxy, yes? So, other Galaxy's such as this exist, and although we can see them via telescopes and other science's, they are clearly a very, very long way away. Fascinating. I don't know why I've not pondered this subject before!

 

Yes we are not near the center of our own galaxy and yes the others are really far away but that may not always be the case. As dhicks has said all galaxies are moving away from a central point, they can tell this by measuring the Doppler shift of the light waves from stars in the other galaxies and even solar systems, kind of like a police speed camera but much cooler. This motion is modified by the gravity of other objects in space and collisions planetary systems and even whole galaxies have been known to crash into each other tearing each other apart.http://johnfenzel.typepad.com/john_fenzels_blog/images/2008/04/27/galaxy_collision.jpg

 

Why is the Milky Way talked about as if it is something we look at, rather than something we are part of?

If you are in a really unpolluted rural area with minimal light pollution you can actually see part of our spiral arm (orion arm) as a white streak across the sky.

http://zuserver2.star.ucl.ac.uk/~idh/apod/image/0710/MilkyWayRoad_landolfi.jpg

There were all sorts kinds mythology built upon its appearance and from that viewpoint it does appear to be something that exists up in the sky rather than something that we are a part of. It is simply so big that it took a very long time in human culture to come to grips with our true place in it and most people still have very little appreciation of how everything actually fits together which is unfortunate.

 

Most of the local group stars that we look at with smaller earth based telescopes that are not on the largest scale are from the local group within the milky way so that could also be where some of that perception comes from. There are some truly huge telescopes though that look much further. The VLT Very Large Telescope - Wikipedia, the free encyclopedia comprises four telescopes with 8.2 meter mirrors each and bigger ones are being built all the time.

Edited April 9, 2010 by SYNACK