Space Porn

Jupiter’s movement may have triggered our moon’s bombardment

New findings from researchers at @NASA and other international teams has discovered a link between the bombardment history of our moon and that of the asteroid Vesta. It appears that the same set of projectiles that hit our moon – and presumably other objects in the inner Solar System – 4 billion years ago also impacted Vesta.

Vesta is an asteroid in our Solar System’s main asteroid belt, between the orbits of Jupiter and Mars. Researchers studying this asteroid have compared moon rocks brought back from the Apollo missions to the findings on Vesta and determined that the same set of projectiles were responsible for both sets of bombardments. And they point to a 4-billion year old disruption of the Solar System:

The findings support the theory that the repositioning of gas giant planets like Jupiter and Saturn from their original orbits to their current location destabilized portions of the asteroid belt and triggered a solar system-wide bombardment of asteroids billions of years ago, called the lunar cataclysm.

The research provides new constraints on the start and duration of the lunar cataclysm, and demonstrates that the cataclysm was an event that affected not only the inner solar system planets, but the asteroid belt as well.

Space Weather

Why Earth’s rotation makes Jupiter’s Red Spot impossible here.

Did you actually think Sandy, Andrew even Katrina were bad? These hurricanes that caused widespread destruction to the U.S. are mere child’s play compared to some storms outside the Earth’s atmosphere. If you were sitting at home on your couch and your local meteorologist began to rant about the latest storm that will bring 400 mph winds and temperatures plunging below -250°F, you would surely think he is lying. Now imagine those conditions lasting for at least 400 years and counting. Well, although this sounds like the makings of a science-fiction movie, this storm does exist as the Great Red Spot on Jupiter.

All major storms on Earth usually have a large center of low atmospheric pressure with cyclonic motion (counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere). These cyclones dominate the Earth’s weather patterns and can cause significant destruction at the same time. However, interestingly, the Great Red spot in Jupiter’s Southern Hemisphere is actually associated with anti-cyclonic (high pressure) flow.

Although there are countless differences between the Great Red Spot on Jupiter and Earth storms, there are also some surprisingly striking similarities. All storms on Earth circulate due to Earth’s rotation.  This rotation deflects the direction of a moving object – a force known as the Coriolis. This deflection allows cyclones to rotate, giving them the ability to strengthen into powerful storms. Since all planets in our solar system rotate, the Coriolis effect is also present, ranging in strength due to size and rotational frequency of the planet. Since Jupiter is the biggest planet in the solar system and makes a complete rotation in only~10 hours, the Coriolis force has an exceptionally strong effect on the planet. This fast rotation is directly related to the strengthening of a storm and wind speeds resulting in a Great Red Spot that has winds up to 400 mph.

The strongest surface wind gust ever recorded on Earth was 253 mph during Cyclone Olivia in the late 90s. Winds at this strength have the ability to demolish almost all buildings in their path. By adding another 150 mph of sustained winds on top of this gust, there most likely would be no evidence that a structure ever existed. But before we put a category 20 hurricane on Earth, it is even possible for conditions like these to be on our planet?

Since, Jupiter rotates two and a half times faster than Earth, causing the stronger Coriolis force and winds, a storm like the Great Red Spot could not exist on Earth.  Thus, you don’t need to worry about a 400 mph storm busting down your door.  Just don’t let the people at the Weather Channel know how strong storms can get on Jupiter or they may have to come up with a whole new list of “storm” names.

Space Porn

Moon river: Cassini spots river of methane on Titan

One of the more unique features of Earth, at least as far as current space exploration has been able to show us, is a “hydrologic system,” or a stable system of liquid transformation from solid to liquid to gas and vapour. On Earth, this system is one made up of water, where precipitation forms rivers, which flow into seas and oceans, and then evaporate back into a gaseous state to restart the whole system over again.

We do however have one very close neighbor which shares a similar feature. Jupiter’s moon Titan, a cold world distant from our sun, has a hydrologic system made of methane.

NASA JPL has released a photograph of a “mini Nile” which empties into a smallish a sea called the Kraken Mare, about the size of the Caspian here on Earth. Like the Nile, it is formed of a large number of tributaries feeding into one relatively straight river basin. Scientists speculate that the straightness of the main column may suggest that the river actually marks a fault line in the bedrock of the moon. Whether this indicates some sort of tectonic plate, as it might on Earth, remains a mystery.

Whereas the Nile river is some 4,100 miles long, this newly-photographed river is a scant 200 miles. But the similarities between the features of these two worlds are striking. This also represents the first time an active river has ever been photographed at this resolution outside of our Earth system.