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The Size of the Planet Matters




Mercury
(small)

Venus
(medium sized)

Jupiter
(very large)

Hydrogen (H) less than 1 hour days over the age of the Universe
Helium (He) roughly 1 day 100 times the age of the solar system over the age of the Universe
Oxygen (O) 800 million years over the age of the Universe over the age of the Universe

This table shows the time it takes, on average, for a few common atmospheric gases to escape the gravity of a planet. The table shows that as the planets get larger (more massive), it is harder for the gases to escape. The table shows that the average time for any gas to escape from Jupiter's gravity is much too long. The same is true for all the Giant planets. Therefore it is likely that all the gases in Uranus' atmosphere are probably the original gases swept up by the proto-Uranus.


Return to atmosphere

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Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Uranus' Smog

Besides methane, Uranus' atmosphere contains even more complex molecules. These molecules form layers of smog over the clouds of Uranus, as shown in the picture. ...more

Uranus' Mesosphere

The mesosphere of Uranus is a region of balance between warming and cooling. That essentially means that nothing happens there. Except for diffusion, the atmosphere is still. Upper reaches of the atmosphere,...more

An Overview of Uranus' Atmospheric Structure

As on Earth, the atmosphere of Uranus consists of a troposphere, stratosphere, mesosphere, and thermosphere. The troposphere is the region where the visible clouds are to be found. The stratosphere, as...more

Altitude Changes of the Belts & Zones

On Uranus, as on Jupiter, the winds in the belts and zones blow first in one direction, then in the other direction. The clouds rise up in a belt, and drop down in a zone, as shown in this picture. This...more

Why Uranus looks like a "bullseye"

The clouds on Uranus, like Jupiter, are divided into stripes. On Uranus the stripes are hard to find. The left picture shows the north pole of Uranus. In this picture only the smog can be seen. The clouds,...more

Uranus Clouds, Overview

The clouds of Uranus, made of methane crystals, are found very low in the sky, and are difficult to find beneath the hazey smog of the pla net. False color is used, in the picture of Uranus to the right,...more

A Uranus summer = a Uranus day

In this picture, the Earth and Uranus are both viewed from the top. In the picture of the Earth, the sun is shining from the side. The picture shows that part of the north pole is in daylight and part...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF