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We frequently observe lunar eclipse throughout the year. Have we ever observed Mars Eclipse or Jupiter Eclipse or Saturn eclipse?

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    $\begingroup$ What do you mean by a "Mars eclipse"? The Moon covering Mars as observed by people on the ground? Something else? $\endgroup$ – Mark Olson Sep 9 '18 at 16:47
  • $\begingroup$ @MarkOlson question. I thought he was talking about Earth transits. The surface of Mars gets the occasional annular eclipse from Phobos, never full. Parts of Jupiter, though it doesn't really have a "surface", it's Moons are large enough to cast regular eclipses on parts of the surface of Jupiter. Titan might cast an occasional eclipse over Saturn, I'd have to calculate to be sure. Saturn's rings cause frequent partial ring eclipses over much of Saturn. It needs to be specific what the transit object is. Phobos eclipses have been observed by curiosity on the surface of Mars. $\endgroup$ – userLTK Sep 9 '18 at 23:22
  • $\begingroup$ @userLTK You may be right, but there are so many possible ways to interpret the question, that I think the OP would be more likely to get a satisfactory answer if he clarifies it. $\endgroup$ – Mark Olson Sep 10 '18 at 2:09
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No.

There are two types of eclipse: A lunar eclipse is when the moon goes into the Earth's shadow. We can see a lunar eclipse because the moon is so close to the Earth. If you were standing on the moon, The Earth would look bigger in the sky than the sun. If the Sun, Earth and moon are aligned, the Earth will block out the light from the sun.

Mars and Jupiter are further away. If you were standing on Mars, The Earth would look like a bright star, it would be too far away to block all the light from the sun, even if the Sun, Earth and Mars were perfectly aligned. So there can be no eclipse.

The second type of eclipse is a solar eclipse, when the moon blocks of light from the sun. Since Mars and Jupiter orbit further from the sun than the Earth, they can never block of its light. Venus and Mercury sometimes do cross the face of the sun. This is called a "Transit" of Venus. But all the planets are too far away to block of all the light, so there is no eclipse.

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I agree with James K's answer, but just to play devil's advocate.

Earth is much too small to cause what we think of as an eclipse when viewed from Mars or Jupiter.

But in a sense, a transit is like an annular eclipse. Nobody would ever call a transit an annular eclipse, because it sounds stupid, but it's kind of the same thing. Phobos is smaller than the Sun from the surface of Mars but that's sometimes called an eclipse.

An eclipse is a transit, but most transits are never called eclipses, because the object in transit is much too small, but there's no formal percentage of the sun that must be blocked to earn the title eclipse. Annular Eclipse vs Total is precise, but transit vs annular eclipse is undefined. It's mostly common sense, but it's still undefined.

Fun thought: . . . I wonder if they'll call the planet to planet transits "eclipses" on Trappist-1.

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