Inner Planets – General Science Notes – For W.B.C.S. Examination.
The inner planets (in order of distance from the sun, closest to furthest) are Mercury, Venus, Earth and Mars. After an asteroid belt comes the outer planets, Jupiter, Saturn, Uranus and Neptune. The interesting thing is, in some other planetary systems discovered, the gas giants are actually quite close to the sun.Inner planets – the four inner planets closest to the sun.Continue Reading Inner Planets – General Science Notes – For W.B.C.S. Examination.
– Inner planets all have a metal core and rocky surfaces.
– Have similar geologic features as Earth does, including mountains,
canyons, and craters
A.)Mercury– closest planet to the sun
– Covered in craters
– Almost no atmosphere and no water
– very extreme temperatures= 720K during the day and 120K at night
– Short years (88 earth days) because it is so close to the sun
B.) Venus – Very thick atmosphere made up of mostly carbon dioxide and sulfuric acid
– Greenhouse effect that makes the climate on Venus very hot (over 700K)
– Spins on its axis VERY slowly and in the opposite direction of the other
planets
C.) Earth – Only planet that supports life
– An atmosphere that moderates the temperature and protects us from
harmful radiation from the sun as well as space debris
– Only planet with large amounts of liquid water on the
surface(hydrosphere)
– Distance from a planet to the sun: measured in terms of how far Earth is
from the sun. This distance is called an astronomical unit (AU).
– 1AU =150,000,000 Km
D.)Mars – Mars appears red because of the iron oxide in the soil
– Very thin atmosphere which allows objects from space to impact the
surface
– Olympus Mons- volcano and the largest mountain in the solar system
– Has polar ice caps with frozen CO2 and small amounts of water, but
surface features suggest liquid water may have flowed across Mars in the
past.
Our Solar System is an immense and amazing place. Between its eight planets, 176 moons, 5 dwarf planets (possibly hundreds more), 659,212 known asteroids, and 3,296 known comets, it has wonders to sate the most demanding of curiosities. Our Solar System is made up of different regions, which are delineated based on their distance from the Sun, but also the types of planets and bodies that can be found within them.
In the inner Solar System, we find the “Inner Planets” – Mercury, Venus, Earth, and Mars – which are so named because they orbit closest to the Sun. In addition to their proximity, these planets have a number of key differences that set them apart from planets elsewhere in the Solar System.
For starters, the inner planets are rocky and terrestrial, composed mostly of silicates and metals, whereas the outer planets are gas giants. The inner planets are also much more closely spaced than their outer Solar System counterparts. In fact, the radius of the entire region is less than the distance between the orbits of Jupiter and Saturn.
This region is also within the “frost line,” which is a little less than 5 AU (about 700 million km) from the Sun. This line represents the boundary in a system where conditions are warm enough that hydrogen compounds such as water, ammonia, and methane are able to take liquid form. Beyond the frost line, these compounds condense into ice grains.Some scientists refer to the frost line as the “Goldilocks Zone” — where conditions for life may be “just right.”
Generally, inner planets are smaller and denser than their counterparts, and have few to no moons or rings circling them. The outer planets, meanwhile, often have dozens of satellites and rings composed of particles of ice and rock.
The terrestrial inner planets are composed largely of refractory minerals, such as the silicates, which form their crusts and mantles, and metals such as iron and nickel which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather. All of them have impact craters and tectonic surface features as well, such as rift valleys and volcanoes.
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