True, since the speed of light is finite.
Quasars are the bright centers of young galaxies. Many quasars we can view today existed billions of years ago, and their light is just now reaching us. They are a snapshot of the past, and tell us about how galaxies formed. From wikipedia: "While there was initially some controversy over the nature of these objects, there is now a scientific consensus that a quasar is a compact halo of matter surrounding the central supermassive black hole of a young galaxy."
that portion of the universe that we can see in principle, given the finite age of the universe
No; the two are quite different. The Universe is everything we can see; it contains many galaxies.
Far denser -- almost infinitely more dense -- than it is today. It is a mistake to say that the BB claims that our entire Universe was once the size of a proton. That statement only applies to what is now the VISIBLE universe -- that small sub-set of our Universe that we can now see. While this 93 billion light year diameter ball is pretty large, it is impossible to determine how much more of our Universe is out there, beyond our present ability to see -- the total amount could be infinite. Thus, instead of saying our entire Universe was much SMALLER than it is today, it is more correct to say it was much DENSER.
Photosurveys seem to suggest that we can see maybe 100 billion galaxies, and a reasonable average estimate may be something like 100 billion stars in each galaxy. That puts you at 10 thousand million million million stars right there. But there doesn't seem to be any end to the universe as far as we can see up till now, so we don't know how many more galaxies there might be, out past the ones that we can see.
The distant universe is seen as it was when the light we see now left it, this is as much as 13 to 15 billion years ago.
The steady state Universe model suggests that the Universe has always existed in a constant state with no beginning or end. It proposes that new matter is continuously created to maintain a constant density as the Universe expands. This model has been largely replaced by the Big Bang theory, which offers a different explanation for the origin and evolution of the Universe.
Yes. That's what telescopes allow (and require) that you do. The reason is that the speed of light is finite, so you never see "now", but what happened in the past.
Science has advanced to the point where we can infer something about the entire universe. This has been a great challenge considering how unimaginably vast the universe is. The countless stars you see in the darkest sky constitute merely 3000 neighbors out of about 300,000,000,000 stars in our galaxy, and as many as 100,000,000,000 galaxies exist in the universe. Humans have always wondered: Has the universe always existed like we see it now, or did it somehow start all of a sudden? In the beginning of this past century, we found out in amazement that the entire universe is expanding. This led physicists to deduce that the universe started out in the finite past with a minuscule size. Realizing that the universe had a beginning, and awed by its vastness and its creations, people have asked: How did the universe begin? After all, we are here to be amazed by it because the universe eventually created lives like us. Now, after decades of observing and thinking, we have come to answer confidently the question of the origin of our universe... with what is known as the "big bang".
We can't see past the cosmological horizon because it represents the limit of the observable universe due to the expansion of space. Light from objects beyond this horizon has not had enough time to reach us since the beginning of the universe.
an idea
Space has existed for approximately 13.8 billion years, which is the age of the universe according to current scientific estimates. This is based on the Big Bang theory, which suggests that the universe began as extremely hot and dense, expanding and cooling over time to form the vast expanse of space we see today.
Bacteria, viruses, algae, ferns, trees much like the ones we see now, turtles, fish, birds (latest thinking is that they existed alongside dinosaurs)... worms, shelled sea life..
Past sins that have been forgiven, and now covered by Christ's blood.
People have always been cruel. Murder, kidnap and torture have ALWAYS existed everywhere across the world. The difference now is that TV and internet allow us to INSTANTLY see acts of cruelty EVERYWHERE in the world that they happen. This was not so in the past.
Right now, the farthest spacecraft is the Voyagers which were launched in the 70's. But, they are only just out of our solar system. The universe as we know right now, is infinite. But, Hubble can see things that are unbelievable distances away.
Because, it tells us that rock cycles are the same now as they were in the past. So to know whats happening with rock cycles now, they can just look back to prior expeirences. - Your wwelcome!!!