Sidusglacies - ⚡️

Venus has LOCKED tectonic plates??? How does that work? How are they even counted as individual plates if it’s the tectonic equivalent of Pangea?

it's not so much that Venus's tectonic plates are locked, it's more that it never had them in the first place!

which is a major surprise, actually, because Venus is the most Earth-like of the other planets in our solar system.

surprise?

"what," you may say, flailing in consternation, "about Mars?? why are we trying to colonize Mars if Venus is more Earth-like???"

and it's a good question! Venus IS technically more Earth-like in the sense that it's right next door, is a solid 80% the size of Earth, and has both a working atmosphere and a liquid mantle composed of molten rock, BUT- it's also important to note that Venus is the hottest planet in the solar system and it rains boiling sulfuric acid at almost all times! our first probes to the damn place actually melted. MELTED.

this is what Hell looks like.

BUT ANYWAY so Venus is the planet in our solar system that's the MOST physically similar to Earth, our dear mother who does not rain boiling sulfuric acid on our heads hardly at all ever, so it's kind of a shock that its geology is COMPLETELY FUCKING DIFFERENT.

see, Earth's outer crust is broken up into a series of mind-breakingly-massive tectonic plates that sort of skid around on top of the liquid mantle, slowly drifting in different directions driven by Earth's rotation and bonking into each other randomly like a 300-million-year-long Pinball tournament!

but on Venus, the entire outer crust is a single solid piece sitting on top of the liquid mantle, like the peel of an orange.

though not as good for you. because of the whole Boiling Acid thing.

and contrary to what you might think, this actually makes Venus a VERY VIOLENT place! the outer crust twists and deforms slightly as the liquid mantle spins under it, like a water balloon being flung repeatedly against a wall by a small child, but all of that force can't really be dispersed because the crust is a single solid piece of rigid rock!

so what happens is that this force builds and builds and BUILDS until Venus can't take the strain anymore and has a very volcanic tantrum about it.

unlike the rest of the solar system, the surface of Venus is made of relatively new and entirely volcanic rock- because the entire planet is basically having a planet-wide eruption event at all times, with multiple huge volcanos just spewing gigantic amounts of liquid rock everywhere like it's their damn job, to the point where Venus is just getting resurfaced like a McDonalds parking lot every epoch or so.

aren't you glad Earth doesn't do this? I am SO glad Earth doesn't do this.

(much, anyway)

uh anyway that's why we're trying to colonize Mars instead, and why plate tectonics are a GOOD thing! thanks for coming to my TED talk bye

Solar System 10 Things to Know: Planetary Atmospheres

Every time you take a breath of fresh air, it’s easy to forget you can safely do so because of Earth’s atmosphere. Life on Earth could not exist without that protective cover that keeps us warm, allows us to breathe and protects us from harmful radiation—among other things.

What makes Earth’s atmosphere special, and how do other planets’ atmospheres compare? Here are 10 tidbits:

1. On Earth, we live in the troposphere, the closest atmospheric layer to Earth’s surface. “Tropos” means “change,” and the name reflects our constantly changing weather and mixture of gases. 

It’s 5 to 9 miles (8 to 14 kilometers) thick, depending on where you are on Earth, and it’s the densest layer of atmosphere. When we breathe, we’re taking in an air mixture of about 78 percent nitrogen, 21 percent oxygen and 1 percent argon, water vapor and carbon dioxide. More on Earth’s atmosphere›

2. Mars has a very thin atmosphere, nearly all carbon dioxide. Because of the Red Planet’s low atmospheric pressure, and with little methane or water vapor to reinforce the weak greenhouse effect (warming that results when the atmosphere traps heat radiating from the planet toward space), Mars’ surface remains quite cold, the average surface temperature being about -82 degrees Fahrenheit (minus 63 degrees Celsius). More on the greenhouse effect›

3. Venus’ atmosphere, like Mars’, is nearly all carbon dioxide. However, Venus has about 154,000 times more carbon dioxide in its atmosphere than Earth (and about 19,000 times more than Mars does), producing a runaway greenhouse effect and a surface temperature hot enough to melt lead. A runaway greenhouse effect is when a planet’s atmosphere and surface temperature keep increasing until the surface gets so hot that its oceans boil away. More on the greenhouse effect›

4. Jupiter likely has three distinct cloud layers (composed of ammonia, ammonium hydrosulfide and water) in its “skies” that, taken together, span an altitude range of about 44 miles (71 kilometers). The planet’s fast rotation—spinning once every 10 hours—creates strong jet streams, separating its clouds into dark belts and bright zones wrapping around the circumference of the planet. More on Jupiter›

5. Saturn’s atmosphere—where our Cassini spacecraft ended its 13 extraordinary years of exploration of the planet—has a few unusual features. Its winds are among the fastest in the solar system, reaching speeds of 1,118 miles (1,800 kilometers) per hour. Saturn may be the only planet in our solar system with a warm polar vortex (a mass of swirling atmospheric gas around the pole) at both the North and South poles. Also, the vortices have “eye-wall clouds,” making them hurricane-like systems like those on Earth.

Another uniquely striking feature is a hexagon-shaped jet streamencircling the North Pole. In addition, about every 20 to 30 Earth years, Saturn hosts a megastorm (a great storm that can last many months). More on Saturn›

6. Uranus gets its signature blue-green color from the cold methane gas in its atmosphere and a lack of high clouds. The planet’s minimum troposphere temperature is 49 Kelvin (minus 224.2 degrees Celsius), making it even colder than Neptune in some places. Its winds move backward at the equator, blowing against the planet’s rotation. Closer to the poles, winds shift forward and flow with the planet’s rotation. More on Uranus›

7. Neptune is the windiest planet in our solar system. Despite its great distance and low energy input from the Sun, wind speeds at Neptune surpass 1,200 miles per hour (2,000 kilometers per hour), making them three times stronger than Jupiter’s and nine times stronger than Earth’s. Even Earth’s most powerful winds hit only about 250 miles per hour (400 kilometers per hour). Also, Neptune’s atmosphere is blue for the very same reasons as Uranus’ atmosphere. More on Neptune›

8. WASP-39b, a hot, bloated, Saturn-like exoplanet (planet outside of our solar system) some 700 light-years away, apparently has a lot of water in its atmosphere. In fact, scientists estimate that it has about three times as much water as Saturn does. More on this exoplanet›

9. A weather forecast on “hot Jupiters”—blistering, Jupiter-like exoplanets that orbit very close to their stars—might mention cloudy nights and sunny days, with highs of 2,400 degrees Fahrenheit (about 1,300 degrees Celsius, or 1,600 Kelvin). Their cloud composition depends on their temperature, and studies suggest that the clouds are unevenly distributed. More on these exoplanets›

10. 55 Cancri e, a “super Earth” exoplanet (a planet outside of our solar system with a diameter between Earth’s and Neptune’s) that may be covered in lava, likely has an atmosphere containing nitrogen, water and even oxygen–molecules found in our atmosphere–but with much higher temperatures throughout. Orbiting so close to its host star, the planet could not maintain liquid water and likely would not be able to support life. More on this exoplanet›

Read the full version of this week’s Solar System 10 Things to Know HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.  

thought i’d post since it is very truthful!

Retrograde motion of Mars in the night sky of the Earth.

Image Credit: Tunc Tezel

source

What drives auroras on Saturn? To help find out, scientists have sorted through hundreds of infrared images of Saturn taken by the Cassini spacecraft for other purposes, trying to find enough aurora images to correlate changes and make movies. Once made, some movies clearly show that Saturnian auroras can change not only with the angle of the Sun, but also as the planet rotates. Furthermore, some auroral changes appear related to waves in Saturn's magnetosphere likely caused by Saturn's moons. Pictured here, a false-colored image taken in 2007 shows Saturn in three bands of infrared light. The rings reflect relatively blue sunlight, while the planet itself glows in comparatively low energy red. A band of southern aurora in visible in green. In has recently been found that auroras heat Saturn's upper atmosphere. Understanding Saturn's auroras is a path toward a better understanding of Earth's auroras.

Image Credit: NASA, Cassini, VIMS Team, U. Arizona, U. Leicester, JPL, ASI

Mammatus clouds are a relatively rare and dramatic variety. (Image and video credit: M. Olbinski)