Could we see a galaxy that is 20 billion light years away assume that we mean a lookback time of 20 billion years?
Could we see a galaxy that is 20 billion light-years away? (Assume that we mean a "lookback time" of 20 billion years.) No, because it would be beyond the bounds of our observable universe..
How does astronomy answer the question what are we?
Astronomy is the study of everything in the universe beyond Earth's atmosphere.
That includes objects we can see with our naked eyes, like the Sun , the Moon , the planets, and the stars ..
How would you classify the sun based on each of these characteristics?
For a perfectly circular orbit, the eccentricity is 0; with increasing elongation of the orbit's shape, the eccentricity increases toward a value of 1, the eccentricity of a parabola..
What are some questions about astronomy?
As they expand and contract, their brightness changes.
Cepheid variables are named for the first known example of the type, the star Delta Cephei, discovered to be variable in 1874..
What is the most likely reason that there are no giant planets beyond Neptune?
A) Any planets forming beyond Neptune would have drifted out of the solar system due to the weakness of the Sun's gravity at this distance..
What is the study of astronomy involves?
Since Earth is rotating, the telescope must have a motorized drive system that moves it very smoothly from east to west at exactly the same rate that Earth is rotating from west to east, so it can continue to point at the object being observed..
What is the time for the moon to rotate around its own axis relative to the stars?
It also takes approximately 27 days for the moon to rotate once on its axis.
As a result, the moon does not seem to be spinning but appears to observers from Earth to be keeping almost perfectly still.
Scientists call this synchronous rotation..
Who discovered astronomy?
How does astronomy help answer the question 'what are we'? It locates us in space and time.
It shows how we fit into the physical processes that govern the Universe..
Who first showed that light does not travel at infinite speed?
Around 1676, Danish astronomer Ole Roemer became the first person to prove that light travels at a finite speed..
Why do Cepheid variables have that strange name?
As they expand and contract, their brightness changes.
Cepheid variables are named for the first known example of the type, the star Delta Cephei, discovered to be variable in 1874..
Why do Cepheid variables have that strange name?
The Sun is classified as a G2 V star, with G2 standing for the second hottest stars of the yellow G class—of surface temperature about 5,800 kelvins (K)—and the V representing a main sequence, or dwarf, star, the typical star for this temperature class..
- An enduring myth about the Moon is that it doesn't rotate.
While it's true that the Moon keeps the same face to us, this only happens because the Moon rotates at the same rate as its orbital motion, a special case of tidal locking called synchronous rotation. - As they expand and contract, their brightness changes.
Cepheid variables are named for the first known example of the type, the star Delta Cephei, discovered to be variable in 1874. - Parallax is: An apparent change in an object's position due to a change in perspective of the observer.
The distance to a star is related to its parallax.
