At present the universe is expanding, but we are not certain if this expansion will continue forever, come to a stop, or if the universe will ultimately collapse back into itself
What observational tests are possible to test among these three possibilities?
The possibilities can be tested by measuring the density of the universe. If the density is too low the universe expands forever; if too high the universe stops and collapses. Also, measuring the amount by which the rate of past expansion differed from the current rate (by studying redshifts) can reveal the rate at which expansion is slowing and so what will happen.
You might also like to view...
A solar eclipse occurs on Earth when the
What will be an ideal response?
How can interstellar dust block starlight in spite of its extremely low density?
What will be an ideal response?
Which is closest to the temperature of the core of the Sun?
A) 10,000 K B) 100,000 K C) 1 million K D) 10 million K E) 100 million K
When an object is at rest, and stays at rest, it might have several forces acting on it. However,
A. the forces are all in the same direction. B. there can only be one force opposite gravity, since weight depends on mass. C. dynamic equilibrium can never be achieved except in the total absence of all forces. D. the forces balance out to net force of zero.