Because they don't have any moons. The easiest way to determine the mass of a planet is the measure the distance of its moon and the time that moon takes to orbit around the planet.
It's 77,248,512 km from Venus to Mercury. It would take you 386.24 hours or 16.09 whole days of 24 hours.
Since Earth's Moon was likely formed from a chance collision, the formation of moons may not have been a stable process in the inner solar system. Any moons that formed around Venus or Mercury could have been swept away by the stronger gravity of the Sun, as might smaller moons around Earth. If Mercury or Venus ever had satellites, they were lost long ago.
Although being closer to the sun, Mercury is the colder of the two planets. Venus's thick atmosphere allows for a greater greenhouse effect, trapping heat easily and retaining it for longer than Mercury can.
Mariner 10 was a space probe launched in November 1973, which flew by Venus and onto mercury. It took about 5 months to get to mercury back then. Maybe with a faster rocket and more modern technology, a trip to mercury might be around 3 months long.
Venus and Mercury. Mars has 24 hours and 37 minutes in a day.
Venus : about 243 Earth days. Mercury about 58.65 Earth days.
mercury is hotter Venus has long been considered the hottest planet due to the cloud cover and its creating an enormous greenhouse effect. I do not believe Mercury is hotter.
It's Mercury or Venus depending on whichthe definition of "day "you mean.
117 earth days is equal to 1 Venus day. (including night time.) Mercury's day is the equivalent to 176 earth days.
It's 77,248,512 km from Venus to Mercury. It would take you 386.24 hours or 16.09 whole days of 24 hours.
Since Earth's Moon was likely formed from a chance collision, the formation of moons may not have been a stable process in the inner solar system. Any moons that formed around Venus or Mercury could have been swept away by the stronger gravity of the Sun, as might smaller moons around Earth. If Mercury or Venus ever had satellites, they were lost long ago.
i am pretty sure Mercury, venus, and Pluto
The planet is Mercury. (Some people think it is Venus, but it is Mercury.)
The "Solar day" on Venus. Or, the "Sidereal day" on Mercury.
Although being closer to the sun, Mercury is the colder of the two planets. Venus's thick atmosphere allows for a greater greenhouse effect, trapping heat easily and retaining it for longer than Mercury can.
Mariner 10 was a space probe launched in November 1973, which flew by Venus and onto mercury. It took about 5 months to get to mercury back then. Maybe with a faster rocket and more modern technology, a trip to mercury might be around 3 months long.
none. Mars Earth and Venus have relatively thick atmospheres. it was long assumed that Mercury did not have an atmosphere but a very thin atmosphere around the planet. Mercury's atmosphere is composed of: 42%O2 29%Na 22%H2 06%He 00.5%K