On Earth, do we see Mars have phases like our Moon does? Do we see Mercury's too?

Question

Consider the planet Mars, which orbits the Sun in a more distant orbit than the Earth. Do you expect that on Earth we see Mars have phases? Why or why not?

Consider the planet Mercury, which orbits the Sun in an orbit inside of the Earth's orbit. Do you expect that on Earth we see Mercury have phases? Why or why not?

Answer 1

With telescopes, we do.

Except that we never see Mars less than gibbous.  Mars's orbit is outside ours, so that we can never see it from the side (relative to the Sun) or closer to the Sun.  Therefore, we never see a half-Mars or a crescent Mars.

Answer 2

Mercury goes through a full range of phases like the moon. Mars, being farther from the sun than earth, goes through slight phases but is always at least 84% illuminated. To see a "half mars" it would have to be at least as near the sun as the earth is.

Answer 3

Well, we obviously wouldn't be able to see a "full" Mercury, or a "full" Venus, since the planets are on the other side of the Sun when that happens.  And we cannot see a "new" phase of the planets farther from the Sun than us because they would have to be between the Earth and the Sun for that to happen.  But, as long as the sun doesn't block our view of the other planets, then yes, the other planets have phases.

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Answer 4

Mars or any "superior" planet will not go through phases like the moon.  Unless they are at or near opposition they will appear to be a somewhat gibbous phase, this effect is maximum at or near quadrature.  Inferior planets (Venus and Mercury) do show phases similar to the moon.  We would never see them "full" actually, because they will be on the opposite side of the sun at this time.

Answer 5

Only inner planets show the crecent phases. Mercury yes.Mars No.

Answer 6

mercury, yes.

mars, not really. a slight gibbous phase at times.

draw a diagram to see why.

Answer 7

I have not seen phases on Mercury.  Mercury is hard to see, and is often close to the Sun.  I'm simply not interested enough in seeing Mercury as a slightly bigger dot to risk blinding myself by pointing a telescope at the Sun without a solar filter even a little.

I have seen phases of Venus.  It's a planet closer to the Sun than us.  I haven't seen "full Venus" because that's on the other side of the Sun, and once again very close to it.  But "quarter Venus" and "pretty thin crescent Venus, yes.  Venus is so bright in my 254 mm scope that i use my Moon filter to see it.  And, it makes the image much sharper.  Oxygen 3 filters work good too - though it makes Venus look blueish green.

Mars doesn't become a crescent because it orbits farther from the Sun than the Earth.