Mitch Cronin Posted May 1, 2010 Share Posted May 1, 2010 When we look out to distant galaxies, we're seeing them as they were, and where they were, millions and billions of years ago... They're all racing away from us --with the exception of those in the "Local Group" -- and the more distant they are, the faster their receding velocity is... So when we can look back to galaxies as far as what's been pegged as the age of the universe, 9.7 bly away, will we see the entire universe all at once? Link to comment Share on other sites More sharing options...
Moon The Loon Posted May 1, 2010 Share Posted May 1, 2010 That musta been one helluva Friday night you just had Link to comment Share on other sites More sharing options...
skyline Posted May 2, 2010 Share Posted May 2, 2010 I like the way you think Mitch Link to comment Share on other sites More sharing options...
conehead Posted May 2, 2010 Share Posted May 2, 2010 "... or sleeping late, playing with their children, catching a few fish, taking a siesta with their spouses and spending their evenings drinking and enjoying their friends..."There it is! The whole universe at a glance! Link to comment Share on other sites More sharing options...
Kip Powick Posted May 2, 2010 Share Posted May 2, 2010 "... or sleeping late, playing with their children, catching a few fish, taking a siesta with their spouses and spending their evenings drinking and enjoying their friends..."I do that already........... Link to comment Share on other sites More sharing options...
AME Posted May 2, 2010 Share Posted May 2, 2010 So when we can look back to galaxies Do we actually look further back? or are we simply able to see dimmer light sources? I don't think we will ever be able to see the light closer to it's source until we are able to bend time as the speed of light is a constant. Link to comment Share on other sites More sharing options...
shediac Posted May 2, 2010 Share Posted May 2, 2010 When we look out to distant galaxies, we're seeing them as they were, and where they were, millions and billions of years ago... They're all racing away from us --with the exception of those in the "Local Group" -- and the more distant they are, the faster their receding velocity is... So when we can look back to galaxies as far as what's been pegged as the age of the universe, 9.7 bly away, will we see the entire universe all at once? Mitch when we die and go to heaven(well some of us),it will all become very clear.This little piece of rock we call earth,will seem a lot more insignificant then it already is:Dancing-Chilli: Link to comment Share on other sites More sharing options...
sustainable Posted May 2, 2010 Share Posted May 2, 2010 "...when we die and go to heaven..."I find myself becoming more and more like an evangelical christian. Whenever I find people who hold irrational beliefs I think, how can I make a buck off that? Link to comment Share on other sites More sharing options...
Moon The Loon Posted May 2, 2010 Share Posted May 2, 2010 I find myself becoming more and more like an evangelical christian. Whenever I find people who hold irrational beliefs I think, how can I make a buck off that?That's the funniest thing I've read here in a long time!!! Link to comment Share on other sites More sharing options...
Mitch Cronin Posted May 2, 2010 Author Share Posted May 2, 2010 So when we can look back to galaxies Do we actually look further back? or are we simply able to see dimmer light sources? I don't think we will ever be able to see the light closer to it's source until we are able to bend time as the speed of light is a constant.I'm not sure I know what you mean Brett... ?When you look at the Hubble Ultra Deep Field image, you're seeing galaxies in the image that are as much as nine billion light yrs. distant. ...which means that we're seeing them as they were nine billion years ago. And, it means, I think, we're seeing them where they were 9b years ago [actually, in the infrared, some may be as far as 9.2 bly! - when the universe was only 500,000,000 yrs old! -- HUDF siteSo.... I'm trying to wrap my head around what we'd see if we could/when we can look far enough to see anything 9.7bly away... wouldn't that have to be right beside every other early galaxy -including our own? ... I guess I'm not familiar enough with the basics of "The Standard Model" that includes the Big Bang... but it would seem to me we shouldn't be able to look any further than that, and what we ought to see is just a background field of glowing gas...? Thanks Skyline... I know that won't always apply... Link to comment Share on other sites More sharing options...
Mitch Cronin Posted May 2, 2010 Author Share Posted May 2, 2010 "... or sleeping late, playing with their children, catching a few fish, taking a siesta with their spouses and spending their evenings drinking and enjoying their friends..."There it is! The whole universe at a glance! Link to comment Share on other sites More sharing options...
moeman Posted May 2, 2010 Share Posted May 2, 2010 But.......since you didn't exist 9 billion years ago, are you really seeing anything? If you could see far enough back, and knew exactly where to look, could you witness the Big Bang itself? Link to comment Share on other sites More sharing options...
shediac Posted May 2, 2010 Share Posted May 2, 2010 "...when we die and go to heaven..."I find myself becoming more and more like an evangelical christian. Whenever I find people who hold irrational beliefs I think, how can I make a buck off that?you must be a pilot,probably on a dash8(sorry to the other pros who fly dash 8)if people don,t see things the way you do,they must be irrationalhmmm,you sound God like Link to comment Share on other sites More sharing options...
Mitch Cronin Posted May 2, 2010 Author Share Posted May 2, 2010 If you could see far enough back, and knew exactly where to look, could you witness the Big Bang itself?I'm not at all sure it should matter where you look, since everything was right there when it happened... Link to comment Share on other sites More sharing options...
Moon The Loon Posted May 3, 2010 Share Posted May 3, 2010 I'm not at all sure it should matter where you look, since everything was right there when it happened... Which "Big Bang" is he talking about? There've been billions of them.Oh wait...does anyone think there was only ONE???How human... Link to comment Share on other sites More sharing options...
AME Posted May 3, 2010 Share Posted May 3, 2010 I'm not sure I know what you mean Brett...?The way I understand it, and I could be wrong, is that our ability to see dimmer sources of light (ie Further away) has improved dramatically, however no matter how much we magnify the light, it still takes the same amount of time to get here....299,792,458 metres per second.... so are we really looking back in time? or are we simply seeing more distant stars? Link to comment Share on other sites More sharing options...
AME Posted May 3, 2010 Share Posted May 3, 2010 And, it means, I think, we're seeing them where they were 9b years ago [actually, in the infrared, some may be as far as 9.2 bly! - when the universe was only 500,000,000 yrs old! -- HUDF site How do we know it was 9b years ago? the light source is 9bly away but without knowing the rate of expansion and the direction (is it 180 degrees from us?) the light may be 9.2 bly away but it could have only been 4.6b years ago? Link to comment Share on other sites More sharing options...
Mitch Cronin Posted May 3, 2010 Author Share Posted May 3, 2010 The way I understand it, and I could be wrong, is that our ability to see dimmer sources of light (ie Further away) has improved dramatically, however no matter how much we magnify the light, it still takes the same amount of time to get here....299,792,458 metres per second.... so are we really looking back in time? or are we simply seeing more distant stars?Because it's taken X time for the light to reach us, we see what they appeared as, X time ago. Imagine you sent a morse code light signal to an alien friend on a planet one light year away.... He won't receive the message for a year... it'll be old news.... include a recent photo of yourself in a computer generated, laser based, data signal... when he get's it, you'll be a year older, but his vision of you will be that fresh picture you took a year ago.How do we know it was 9b years ago? the light source is 9bly away but without knowing the rate of expansion and the direction (is it 180 degrees from us?) the light may be 9.2 bly away but it could have only been 4.6b years ago?Very few velocities, including relative velocities of any galaxies we see, even come close to relative relevance when compared to the speed of light.... until you reach what is so far theoretical distances where the universe's expansion rate can mean relative velocities between extremely distant galaxies can even exceed the speed of light [in which case we'd never see them, since their distance is always increasing by an amount greater than their light travels in the same time]... But I think you're right, and I suspect some small allowance for relative velocities needs to be considered when calculating distances.(is it 180 degrees from us?) relative to what? Direction, in space, is only available in relation to something else ... we might choose a purely arbitrary direction we derive from our own plane of rotation, or our own orbital plane, or our own galactic plane..., but what relevance does 180 degrees from any of those have? We have no way to determine a center of the universe. Link to comment Share on other sites More sharing options...
Moon The Loon Posted May 3, 2010 Share Posted May 3, 2010 Seek the multiplicity of big bangs, Mitch. Seek the MULTI-plicity.Or, if you wish, embrace infinity. 'member Dr. Zorba? Link to comment Share on other sites More sharing options...
Miles Posted May 3, 2010 Share Posted May 3, 2010 I suspect that if we can see 'far enough' back in time we'd see younger and younger and closer together galaxies, wouldn't we? I dunno, I'm still trying to wrap my brain around the properties of light. So, am I to understand that no matter what speed I'm travelling, the speed of light is the same in all directions, right? So if an observer is travelling a little faster that 1/2 the speed of light in 1 direction, and the object the observer is viewing is moving in the opposite direction a little faster than 1/2 the speed of light, would the observer see the object?Also, using doppler effect they've been observing a blue and red shift in galaxies moving away from, and towards us... so how can the speed of light be the same in all directions if there's a doppler effect? Link to comment Share on other sites More sharing options...
Miles Posted May 3, 2010 Share Posted May 3, 2010 also mind blowing to me is something related, that is the effect of gravity. Gravity acts on an object at the speed of light... Which means that if the sun winked out of existence, the earth would stay in orbit for another 9 or so minutes before shooting of on a tangent. Link to comment Share on other sites More sharing options...
Moon The Loon Posted May 3, 2010 Share Posted May 3, 2010 Not quite. The gravitational constant is the releationship of the force of the gravitational attraction between two bodies to their masses and their distance from each other in Newton's law of gravitation. The gravitational constant equals approximately 6.67259 × 10-11 newton square meters per square kilogram. Its symbol is G.Which is nowhere close to C Link to comment Share on other sites More sharing options...
Mitch Cronin Posted May 3, 2010 Author Share Posted May 3, 2010 What he means Moon, is that the force of gravity is carried at the speed of light.... the gravitons will still be exerting a force on a body even after the instant their producer isn't there (presuming one could imagine an instantaneous disappearance of the body that emitted the gravitational force) ...Doppler, or red-shift, is relative to the observer.... which gets into something I have trouble with too... the relativity of light speed.... If i'm moving toward you at light speed, and I turn on a laser, pointed at you, when I'm 1 light year away, the light should first reach you, one year later... from my perspective... since the light is moving away from me at light speed... I should be able to calculate that the light will hit your face when I'm half way to you, or half a light year away, but that can't be so, since, from your perspective, that would mean I wasn't 1 light year away at all.... and both me and the light will be traveling at the same speed........ which would mean I couldn't have sent it when I was 1 light year away, because it took me 1 year to get to you, and I know the light got to you in half the time it took me... :Scratch-Head: :Scratch-Head: Link to comment Share on other sites More sharing options...
Mitch Cronin Posted May 3, 2010 Author Share Posted May 3, 2010 Just one of untold billions of galaxies....How many worlds might exist within that incredible collection of stars...? Link to comment Share on other sites More sharing options...
J.O. Posted May 3, 2010 Share Posted May 3, 2010 That's a collection of stars? For a minute there I was thinking that someone had pulled the "Emergency Dump" lever on the ISS! Link to comment Share on other sites More sharing options...
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