attain. English Collins Dictionary-English synonyms & Thesaurus &nbsp. attain (attains 3rd person present) (attaining present participle) (attained past tense & past participle) 1 verb If you attain something, you gain it or achieve it, often after a lot of effort. FORMAL Jim is halfway to attaining his pilot's licence.
The length of day on Mercury is 58.646 Earth days. This is a sidereal day, which is the amount of time it takes Mercury to turn once on its axis compared to the background stars. If you could look down from above Mercuryâs north pole, it would take almost 59 days to turn in a counter-clockwise direction. Mosaic of Mercury. Credit: NASA / JHUAPL / CIW / mosaic by Jason Perry. Things get unusual because a year on Mercury only lasts 88 days. And a solar day on Mercury lasts 176 Earth days. In other words, if you could stand on the surface of Mercury, it would take 176 days for the Sun to return to the same spot in the sky. Astronomers used to suspect that Mercury was tidally locked to the Sun, and always showed the same face to the Sun; similar to how the Moon is tidally locked to the Earth.
In this exercise, you will calculate the solar day for a person on Mercury. The period of revolution, the time interval for Mercury to orbit the Sun (relative to the stars), for Mercury is 88 days (and when I say âdayâ as a unit, I am referring to Earth days). Mercuryâs period of rotation, the time interval to rotate once about its axis (relative to the stars), is 59 daysâthis is 2/3 of the orbital period of Mercury. What is the deï¬nition of solar day? What is the deï¬nition of sidereal day? A picture of Mercuryâs orbit is shown below.