Search results
Results from the WOW.Com Content Network
Mercury's sidereal year (88.0 Earth days) and sidereal day (58.65 Earth days) are in a 3:2 ratio. This relationship is called spin–orbit resonance, and sidereal here means "relative to the stars". Consequently, one solar day (sunrise to sunrise) on Mercury lasts for around 176 Earth days: twice the planet's sidereal year.
Reaching Mercury from Earth poses significant technical challenges, because the planet orbits so much closer to the Sun than does the Earth. A Mercury-bound spacecraft launched from Earth must travel 91 million kilometers into the Sun's gravitational potential well. [12] Starting from the Earth's orbital speed of 30 km/s, the change in velocity ...
The orbit of the planet Mercury lies interior to that of the Earth, and thus it can come into an inferior conjunction with the Sun. When Mercury is near the node of its orbit, it passes through the orbital plane of the Earth. If an inferior conjunction occurs as Mercury is passing through its orbital node, the planet can be seen to pass across ...
Instead, flyby and orbital missions to Mercury can study the planet and receive accurate data. Even though Mercury is closer to Earth than Pluto is, the transfer orbit from Earth to Mercury requires more energy. Mercury being so close to the Sun, space probes going there are accelerating as they approach, due to the Sun's gravitational pull.
The geology of solar terrestrial planets mainly deals with the geological aspects of the four terrestrial planets of the Solar System – Mercury, Venus, Earth, and Mars – and one terrestrial dwarf planet: Ceres. Earth is the only terrestrial planet known to have an active hydrosphere.
Earth's orbit: 299.2 million km [b] 2 AU [c] 2.99×10 8: The average diameter of the orbit of the Earth relative to the Sun. Encompasses the Sun, Mercury and Venus. [18] Inner Solar System ~6.54 AU 9.78×10 8: Encompasses the Sun, the inner planets (Mercury, Venus, Earth, Mars) and the asteroid belt.
Mercury retrograde refers to the period of time when Mercury moves slower than the Earth around the sun – causing it to appear to spin backward in the night sky. Retrograde motion is an apparent ...
MESSENGER was a NASA robotic space probe that orbited the planet Mercury between 2011 and 2015, studying Mercury's chemical composition, geology, and magnetic field. [9] [10] The name is a backronym for Mercury Surface, Space Environment, Geochemistry, and Ranging, and a reference to the messenger god Mercury from Roman mythology.