I was reading an old Asimov novel called Pebble in the Sky, and it somewhat irked me that Sirius and Aldebaran were described as major stat systems of the Galactic Empire.
Sirius is too young to have had time to develop planets with higher life (if evolution on Earth is anything to go by), and...
It's that excactly how it should be? Considering our Observable Universe is so tiny compared to the total universe, shouldn't it appear flat no matter what is the actual shape of the total universe?
Thanks, that was a very interesting essay.
100 billion years is not much in the grand scheme of things. So an observable universe where we can observe billions of other galaxies is just a passing phase.
We really do live in an intersting time.
Too bad Kaku has become so full of "kaka".
His book "Hyperspace - Into the 10th Dimension" is the one book that has had the greatest impact on me as a layman interested in cosmology.
So only the Milky Way (or the local cluster) will become the obervable universe from the position of Earth? How many billion years are we talking about before that happens?
And if intelligent life evolves in the Milky Way at that time, will they be able to deduce that there are other galaxies...
But according to the inflation theory our observable universe is only a tiny fraction of the total universe. Won't it thus appear flat now matter the overall shape of the total universe?
One way of looking at it:
The inside of the balloon is the past, with the Big Bang in the center. The surface of the balloon is the present, while outside the balloon is the future.
According to the Inflation Theory our Observable Universe is but a small part of the total universe created in the Big Bang.
Our observable universe appears to be flat (just like Earth at sea level may appear flat), while the total universe may be shaped like a balloon.
If we assume our...
If you and a friend agree to move your bodies to the same place, meet each other, and then move your bodies back to your respective homes is it enough to agree on the place of the meeting?
Is it correct to say that the three space dimensions are no more physically (as in materially) real than the time dimension, but that only the mass that exists in the dimensions are real in a material sense?
I have a suspicion that why som people insist that time (and spacetime) does not exist...
"We can visualize this using the metaphor in which galaxies are dots on a balloon being blown up. No point on the balloon is the center of expansion. If you want to pick out a center, you have to pick a point in the air, not on the surface of the balloon. But in the balloon analogy, the third...
What is the difference between a black hole singularity and the Big Bang singularity?
How does one distinguish one singularity from another? Do they have any properties at all?
If we picture the universe as a ball, and a black hole singularity as having infinite gravity can we picture it as a...