NASA Sees Glow of Universe's First Objects
Damek writes with news from NASA's Spitzer Space Telescope, which has captured light from what may have been the first glowing objects in the universe, light generated 14 billion years ago. From the article: "'We are pushing our telescopes to the limit and are tantalizingly close to getting a clear picture of the very first collections of objects,' said Dr. Alexander Kashlinsky... 'Whatever these objects are, they are intrinsically incredibly bright and very different from anything in existence today.' Astronomers believe the objects are either the first stars — humongous stars more than 1,000 times the mass of our sun — or voracious black holes that are consuming gas and spilling out tons of energy. If the objects are stars, then the observed clusters might be the first mini-galaxies..."
by some more powerful equipment. From New Scientist Space: "Because Hubble's mirror is larger than Spitzer's, it turned up dwarf galaxies too faint for Spitzer to resolve. "Once we remove pixels in the Spitzer images corresponding to the locations of these galaxies, the background infrared light level mostly disappears," Cooray told New Scientist. 'We think, therefore, the infrared light seen in Spitzer images is mostly due to the faint infrared glow from these dwarf galaxies.'" The full article
A good way to think of it is to imagine us as living on the skin of a balloon as it is being blown up. You are moving away from every other point uniformly, but you aren't near the "edge".
In more physics-friendly language, there are only two possibilities - either the universe is open or it's closed. If it's open, then it's infinite in all directions and there is no edge (we don't think this is the case, but it's still technically possible). If it's closed, then there simply is no edge because as you travel in any direction you curve around to head back where you came from.
It might also help to realize that while the visible universe may be "only" 14 billion light years or so in radius, the longest dimension of a closed universe could be several times this number due to inflationary expansion. So we may not be seeing everything that's actually out there.
...following the principles of Heisenburger's Uncertain Cat...
The Sun is a pretty small star compared to others...
Right, but the 1000 times the mass would be a huge star. The most massive stars known today are on the order of 100 times the mass of our sun. So these might be stars that are ~10x larger than the largest currently observed stars.
Ah; Excellent question.
If you look at the "known universe," it appears that we are in the exact middle, dead center, of the known universe.
When we see the Cosmic Microwave Background Radiation, we are seeing "the edge" of the visible universe, that we can see.
As you look further and further away from where we are, you see deeper and deeper into the past, until you see back as far as we can, where we see only the cosmic microwave background radiation, uniformly, like a sphere, in all directions.
Most astrophysicists doubt that we are at the exact middle.
The reason we can't see things beyond the visible universe, is simply because light hasn't existed long enough to get to us, from things that exist beyond the edge of our light cone of vision.
Right? If light has only existed for, say, 14.7 billion light years, then you're not going to be seeing something that's 20 billion light years away. Or 100 billion light years away.
It makes sense that, at the very edge of our vision, we see the genesis of the universe, in all directions.
Astrophysicists today do not know how large the universe is, and it may well be infinite, in all directions. Astrophysicists take this idea very seriously, as far as I understand. That said, they also take seriously the idea that it is smaller than the observable universe, and just has a wrap-around effect.
13.7 billion years later, that first light year has expanded like a rubber sheet to have a disproportionate contribution to the 53 billion, compared to light years that the photon covered later on, just before reaching us. You can't just multiply the total elapsed time by c. You have to actually do an integral over time for the entire trip to get the 53 billion, where the integrand is the product of c by the "stretch factor" S(t) at that point on the trip: the factor by which the space that a photon was flying through at time t has expanded by now (as considered relative to a frame where the Earth is at rest). I don't know what this function would be, but I do know it's a function of time (or more specifically, time since the Big Bang in a frame at rest with respect to the microwave background radiation).
If S(t) were fixed at 1.0, you'd expect an integral of 13.7 billion light years. But it isn't fixed at 1.0; it is always greater than that and only approaches 1.0 at the end since light years at the end of the trip haven't had much time to expand. At the start of the trip S(t) could have been very high, depending on the age of the universe at the time.
The current belief is that more than one of the theories is likely to be wrong, although it is entirely possible that they are all correct depending on the observer and/or universe. (In the Many Worlds theory, there is one instance of the Universe for every possible permutation of valid events that could ever occur. If this theory is correct and the shape of the Universe is dictated by events, then the shape of the Universe is determined by which branch you happen to be on at the time you do the observation. If branches can interact, this may vary between observations.)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)