Turns out, it's as tough to drop inward into the inner solar system, as it is to head outward. The problem stems from losing momentum from a launch starting point on Earth. It can take missions ...

Mercury completes its orbit around the sun in only 88 days, causing it to appear retrograde three or four times a year for about three weeks at a time, according to Farmers' Almanac. Since the ...

Mercury retrograde: Several planets appear to 'step back,' and here's what that means. The planets that fall inside Earth's orbit around the Sun – Mercury and Venus – mostly appear to be ...

Mercury, which takes 88 days to orbit the sun, is visible for only a few weeks ... Uranus and Neptune will also be around, but they won't be appearing as bright and will require a telescope ...

Mercury, Venus, Mars ... are always in a line called an ecliptic – the plane where they orbit the Sun. As the planets race ...