Tag: planetary science

Video from Dawn

9:39 am

NASA has released an update summarizing what scientists have found since Dawn went into orbit around Vesta in July. The video below, compiled from images Dawn has taken, gives a nice visual overview. The most interesting big feature, understated by the video, is the series of grooves that appear to encircle the asteroid’s equator. To my eye it almost looks like Vesta was once two asteroids that got merged into one, with these grooves indicating the weld point.

The direct link to the video can be found here.

Embedded video from

NASA Jet Propulsion Laboratory California Institute of Technology

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Getting closer to Vesta

5:30 pm

close-up thumbnail

The Dawn mission team released another image today of the giant asteroid Vesta, this time taken from about 2,300 miles away. At this distance the resolution is still somewhat coarse, with the smallest visible detail about 0.43 miles in size.

To the right is a cropped section of the full image, focusing in on what appears to be a very strange geological feature, indicated by the arrows. From what I can tell, the dark meandering streak looks like a rille or flow coming out of the mound or peak near the bottom of the image. Yet, this dark meander continues directly across a crater as if it were a wind-blown dust streak.

I really have no idea what geological process created this. I also suspect that the scientists don’t quite know yet either, though I am sure they have some good theories, mostly based on the very light gravity that should exist on a world only 330 miles in diameter. As I’ve already noted, however, it is going to take them a couple of months to digest the data they are getting and come up with some reasonable conclusions. It will be fun to finally find out what they have learned.

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Ethane lakes in a red haze: Titan’s uncanny moonscape

10:33 am

Titan’s ethane lakes in a red haze.

So far, there are no recognisable signs of organic life. That’s not surprising: by terrestrial standards, Titan is a deep freeze with surface temperatures at a chilly -180°C. Yet Titan is very much alive in the sense that its atmosphere and surface are changing before our eyes. Clouds drift through the haze and rain falls from them to erode stream-like channels draining into shallow lakes. Vast dune fields that look as if they were lifted from the Sahara sprawl along Titan’s equator, yet the dark grains resemble ground asphalt rather than sand. It is a bizarrely different world that looks eerily like home. Or as planetary scientist Ralph Lorenz puts it: “our prototype weird-world exoplanet”.

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Pluto’s atmosphere is expanding, and scientists don’t know why

5:59 pm

Pluto’s atmosphere is expanding, and scientists don’t know why.

Pluto travels along a highly elliptical path and last passed closest to the sun in 1989. Many planetary scientists expected the atmosphere to shrink as the icy orb began receding from the sun’s warmth. The unanticipated expansion may be related to changes in the darkness of the orb’s surface a decade or so ago, which may have caused the surface ices to absorb more solar radiation and more efficiently evaporate. Or, Greaves suggests, long-term variations in the sun’s ultraviolet output, changes linked to the roughly 11-year cycle of solar activity, may be playing a role.

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