Solar System Planets' Atmospheres| | Atmospheric Composition | Average Temperature | Surface Pressure | Wind Speeds | Remarks |
|---|
| Mercury | 42% Oxygen (O2)
29% Sodium (Na)
22% Hydrogen (H2)
6% Helium (He)
0.5% Potassium (K)
Others:
possible trace amounts of Argon (Ar), Carbon Dioxide (CO2), Water (H2O), Nitrogen (N2), Xenon (Xe), Krypton (Kr), Neon (Ne) | 440° K (167° C), 650° K on the sunward side | 10-15 bars | none | Mercury has in fact no atmosphere. Small dust
particles and meteoroids hitting the planet and knocking calcium-bearing molecules free from
the surface, a process called impact vaporization, continually renews the
few gases found in Mercury’s exosphere |
| Venus | 96.5% Carbon Dioxide (CO2)
3.5% Nitrogen (N2)
Others (ppm): Sulfur Dioxide (SO2) - 150; Argon (Ar) - 70; Water (H2O) - 20; Carbon Monoxide (CO) - 17; Helium (He) - 12; Neon (Ne) - 7 | 737° K (464° C) | 92 bars | 0.3-1.0 m/s | Venus lacking of an internally generated magnetic field, it lost its hydrogen, a critical component of water. As a result, its oceans evaporated within its first 600 million years, according to estimates. The planet's atmosphere became thick with carbon dioxide, a heavy molecule that's harder to blow away. Venus natural greenhouse effect went uncontrolled |
| Earth | 78.084% Nitrogen (N2)
20.946% Oxygen (O2)
Water is highly variable, typically about 1%
Others (ppm): Argon (Ar) - 9340; Carbon Dioxide (CO2) - 350; Neon (Ne) - 18.18; Helium (He) - 5.24; CH4 - 1.7; Krypton (Kr) - 1.14; Hydrogen (H2) - 0.55 | 288° K (15°.C) | 1014 mb | 0-100 m/s | At 4.6 billion years ago, a thin envelope of hydrogen and helium clung to our molten planet as outbursts from the young Sun stripped away that primordial haze within 200 million years. As Earth's crust solidified, volcanoes gradually coughed up a new atmosphere, filling the air with carbon dioxide, water, and nitrogen. Over the next billion years, the earliest bacterial life consumed that carbon dioxide and, in exchange, released methane and oxygen into the atmosphere. Earth also developed a magnetic field, which helped protect it from the Sun, allowing our atmosphere to transform into the oxygen- and nitrogen-rich air. The natural greenhouse effect induced by the atmosphere is providing a beneficial 30°C more. It might that the original atmosphere to Earth appeared 40 million years after the solar system's creation only instead of 100 like previously thought. Such that primitive atmosphere was mostly nitrogen. Astronomers found in 2014 that nitrogen in the atmosphere of Saturn's moon Titan originated in
conditions similar to the cold birthplace of the most ancient comets from the
Oort cloud. This means the sources of Earth’s and
Titan’s nitrogen must have been different. When Moon crosses Earth's magnetosphere's plasma sheet, significant numbers of energetic ions of nitrogen, oxygen, and noble gases, coming from the Sun, which are implanted into the surface of the lunar regolith, at around tens of nanometres in depth, hinting to the possibility that the Earth’s atmosphere of billions of years ago may be preserved on the present-day lunar surface. Anywhere from a hundred to several hundred tons of the Earth's atmosphere are going into space every day. The energy necessitated by the process are auroras
|
| Moon | helium, neon and argon constitute the Moon's exosphere (the Moon's atmosphere is technically referred to as an
exosphere because it’s so thin and its atoms rarely collide)
Others (ppm): na | na | na | na | The Moon's exosphere is extending a few hundred miles above the surface. Most of the moon's exosphere comes from the solar wind, particles of which impact the moon, but only helium, neon, and argon are volatile enough
to be returned back to space. The rest of the elements will stick indefinitely
to the Moon’s surface. Moon’s exosphere is made up of mostly
helium, argon, and neon. Their relative abundance is dependent on the time of
day on the Moon. Argon peaks at sunrise, with neon at 4 a.m. and helium at 1
a.m. Some gas comes from lunar rocks. Argon-40 results from the decay of naturally
occurring radioactive potassium-40, found in the rocks of all the terrestrial
planets as a leftover from their formation. The argon-40 creates a local bulge above a
unusual part of the moon's surface, the region containing Mare Imbrium and
Oceanus Procellarum, which might hint to deep-located resource and released by tidal-stress outgassing. About 20 percent of the helium is coming from the Moon itself, most
likely as the result from the decay of radioactive thorium and uranium found in lunar rocks. Sunlight also ionizes a portion of the lunar exosphere, producing
an ionosphere roughly one million times weaker than Earth’s |
| Mars |
95.32% Carbon Dioxide (CO2)
2.7% Nitrogen (N2)
1.6%Argon (Ar)
0.13% Oxygen (O2)
0.08% Carbon Monoxide (CO)
Others (ppm): Water (H2O) - 210; Nitrogen Oxide (NO) - 100; Neon (Ne) - 2.5; Hydrogen-Deuterium-Oxygen (HDO) - 0.85; Krypton (Kr) - 0.3; Xenon (Xe) - 0.08 | 210° K (-63° C) | 6.36 mb (variable from 4.0 to 8.7 mb according to season) | 2-7 m/s (summer), 5-10 m/s (fall), 17-30 m/s (dust storm) | Mars lost its atmosphere when it lost its global magnetic field, and in a gradual process over a significant period of time. Ozone, dust and ice
particles are also to be found in the Martian atmosphere. On Mars, ozone is easily destroyed by the byproducts of water vapor breakdown by ultraviolet sunlight. Tenuous oxygen, hydrogen, and carbon coronas are parts of Mars' atmosphere with a highly-variable ozone underneath. The hydrogen and oxygen coronas of Mars are the tenuous outer fringe of the atmosphere. In this region, atoms that were once a part of carbon dioxide or water molecules near the surface can escape to space. The solar wind is stripping away the atmosphere of Mars at a rate of 1/4 pound (about 100 grams) every second. Geological
evidence has led scientists to conclude that ancient Mars was once shrouded in a thick
carbon dioxide atmosphere. A new study by late 2015 proposes that 3.8 billion years ago, Mars might have had a moderately dense
atmosphere. The transition to the current atmosphere would have occurred through two possible mechanisms for the removal of the excess
carbon dioxide. Either the carbon dioxide was incorporated into minerals in
rocks called carbonates (but not enough carbonates were found in Mars' rocks) or it was lost to space through sputterring (but the ratio carbon-12 to -13 does not match that). A mechanism could have significantly
contributed to the carbon-13 enrichment however. The ultraviolet sunlight, when hitting a molecule of carbon dioxide in the upper
atmosphere, it splits it into carbon monoxide and oxygen. When UV light hits
the carbon monoxide it further splits it into carbon and oxygen, all the process called 'ultraviolet photodissociation,' as carbon-12 is far more likely to escape than carbon-13. That strengthens the loss to space theory. Ion
loss at Mars increased during periods of extreme solar activity, suggesting a younger
and more active Sun billions of years. Hint of more oxygen in Mars' early atmosphere added to evidence about ancient lakes might reveal how Earth-like our neighboring planet once was. At Earth the same geological records found at Mars are a important marker of the major shift in our atmosphere's
composition, from relatively low oxygen abundances to a oxygen-rich atmosphere. It looks like oxygen levels also raise at Mars before declining to their present values. The move at Mars resulted from the loss of Mars' protective magnetic field. Ionizing solar radiation started splitting water molecules into hydrogen and oxygen as only the heavier oxygen atoms remained behind because of Mars' low gravity and much of that oxygen went into rocks, leading to the current rusty red dust covering the surface. Regional dust storms at Mars play a role in the process of gas escaping from the top of Mars' atmosphere. There's a increase in water vapor in the middle atmosphere -- roughly 30 to 60 miles (50 to 100 kilometers) high. Loss of hydrogen from the top of the atmosphere was thought occurring at a rather steady rate, with variation tied to changes in the solar wind's flow, but data instead showed a pattern that
appears more related to Martian seasons -- of which regional dust storms -- than to solar activity |
| Pluto |
98% Nitrogen (N) with some methane and carbon monoxyde | na | 10,000 times lower pressure at the surface than at the Earth | na | Nitrogen in Pluto’s atmosphere (in the form of N2 gas) is actually flowing
away and escaping the planet at an estimated rate of hundreds of tons per hour. N resupply is likely heat and geologic activity inside Pluto, like
processing nitrogen out of Pluto’s rocky interior and get it to the surface |
Table of Data About Solar System Planets' Atmospheres
