Like the waistband of a couch potato in midlife, the orbits of planets in our solar system are expanding. It happens because the Sun’s gravitational grip gradually weakens as our star ages and loses mass. Recently, a team of NASA and MIT scientists indirectly measured the Sun's mass loss and other solar parameters by looking at changes in Mercury’s orbit.
The smallest planet in our solar system and nearest to the Sun, Mercury is only slightly larger than Earth's moon. From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as 11 times brighter. Despite its proximity to the Sun, Mercury is not the hottest planet in our solar system—that title belongs to nearby Venus—but it is the fastest, zipping around the Sun every 88 Earth days.
The smallest planet in our solar system and nearest to the Sun, Mercury is only slightly larger than Earth's moon. From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as 11 times brighter. Despite its proximity to the Sun, Mercury is not the hottest planet in our solar system—that title belongs to nearby Venus—but it is the fastest, zipping around the Sun every 88 Earth days.
10 Things to Know About Mercury
1
SMALLEST
Mercury is the smallest planet in our solar system - only slightly larger than the Earth's moon. If the sun were as tall as a typical front door, Earth would be the size of a nickel and Mercury would be about as big as a green pea.
2
INSIDER
It is the closest planet to the sun at a distance of about 58 million km (36 million miles) or 0.39 AU.
3
LONG DAYS, SHORT YEARS
One day on Mercury (the time it takes for Mercury to rotate or spin once with respect to the stars) takes 59 Earth days. One day-night cycle on Mercury takes 175.97 Earth days. Mercury makes a complete orbit around the sun (a year in Mercury time) in just 88 Earth days.
4
ROUGH SURFACE
Mercury is a rocky planet, also known as a terrestrial planet. Mercury has a solid, cratered surface, much like the Earth's moon.
5
CAN'T BREATHE IT
Mercury's thin atmosphere, or exosphere, is composed mostly of oxygen (O2), sodium (Na), hydrogen (H2), helium (He), and potassium (K). Atoms that are blasted off the surface by the solar wind and micrometeoroid impacts create Mercury's exosphere.
6
MOONLESS
Mercury has no moons.
7
RINGLESS
There are no rings around Mercury.
8
TOUGH PLACE TO LIVE
No evidence for life has been found on Mercury. Daytime Temperatures can reach 430 degrees Celsius (800 degrees Fahrenheit) and drop to -180 degrees Celsius (-290 degrees Fahrenheit) at night. It is unlikely life (as we know it) could survive on this planet.
9
BIG SUN
Standing on Mercury's surface at its closest point to the sun, the sun would appear more than three times larger than it does on Earth.
10
ROBOTIC VISITORS
Only two missions have visited this rocky planet: Mariner 10 in 1974-5 and MESSENGER, which flew past Mercury three times before going into orbit around Mercury in 2011.
No comments:
Post a Comment
Comment here...