Elliptical galaxies are classified on a scale from E0 to E7 based on their apparent shape. Which class appears most spherical?
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Scientific notation is used to express very large and very s…
Scientific notation is used to express very large and very small numbers. Which of the following correctly expresses ‘thirty-two hundred thousand meters’ in scientific notation?
The diagram below shows electrons transitioning between ener…
The diagram below shows electrons transitioning between energy levels in an atom, each absorbing a photon. Which transition absorbs the photon with the least energy?
How do astronomers know that hydrogen gas is present in Emis…
How do astronomers know that hydrogen gas is present in Emission nebulae?
A star with a right ascension of 13 hours is crossing the me…
A star with a right ascension of 13 hours is crossing the meridian (transiting) at noon today. At what time will a star with a right ascension of 7 hours transit the meridian?
White dwarfs are stable stellar remnants under most conditio…
White dwarfs are stable stellar remnants under most conditions. Under what circumstances can a white dwarf explode as a supernova?
Brachial means lower leg.
Brachial means lower leg.
Which characteristic of Venus has led many to call it the “s…
Which characteristic of Venus has led many to call it the “sister planet” to Earth?
With no water and a thick, slow-moving lower atmosphere, the…
With no water and a thick, slow-moving lower atmosphere, there is little erosion on Venus
The air on Mars is 95% nitrogen and argon
The air on Mars is 95% nitrogen and argon