Tag: asteroids

New close-up image of Ceres’s double bright spots

9:32 am

close-up of Ceres's bright spots

Cool image time! The Dawn science team has released a some new close-up images of Ceres, including a much higher resolution image of the dwarf planet’s double bright spot, which now resolves itself into a cluster of two larger spots with a half dozen smaller spots scattered nearby.

The region with the brightest spots is in a crater about 55 miles (90 kilometers) across. The spots consist of many individual bright points of differing sizes, with a central cluster. So far, scientists have found no obvious explanation for their observed locations or brightness levels.

“The bright spots in this configuration make Ceres unique from anything we’ve seen before in the solar system. The science team is working to understand their source. Reflection from ice is the leading candidate in my mind, but the team continues to consider alternate possibilities, such as salt. With closer views from the new orbit and multiple view angles, we soon will be better able to determine the nature of this enigmatic phenomenon,” said Chris Russell, principal investigator for the Dawn mission based at the University of California, Los Angeles.

To my eye, these bright areas resemble a wide flat caldera of a volcano. Instead of being at the top of a peak, the caldera is like a lava pool, almost like a large lake. In this case, the large spots are lakes of frozen ice that periodically melt and flow. The smaller spots are likely smaller vents where water can bubble up from below during active periods. When not active, the water will be frozen. Since ice is white and Ceres is very dark, the pools and vents appear extremely bright in these images.

I am speculating however. We will have to wait for much better images to know for sure.

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Rare large meteorite stolen from Australian museum

11:18 am

In a heist reminiscent of a Hollywood movie, two thieves in hooded jumpers and white masks stole a 25 pound meteorite the size of a soccer ball on Monday.

The only value of such a meteorite is among collectors, but to sell such a large and unique meteorite without being noticed would be impossible. It is theorized that the thieves might chop it up and sell the pieces to collectors instead.

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Dawn makes a movie of Ceres

9:28 am

Cool image time! Using images that Dawn has accumulated since it entered orbit around Ceres, scientists have created an animation showing the dwarf planet as it rotates.

Video below the fold. Note that this is an animation. They have filled in the gaps between images to make the rotation smooth, exaggerated the scale two times to bring out details, and added a background of stars that is not visible in the original images. Even so, this video is scientifically useful, as it shows Ceres in its entirety. It is also very spectacular.
» Read more

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Rosetta team proposes landing on comet to finish mission

4:14 pm

Rather than simply turn off the spacecraft when its funding runs out at the end of 2015, Rosetta’s science team have proposed that the mission get a nine month extension, during which they will slowly spiral into the comet and gently land.

Their proposal is similar to what American scientists did with their NEAR spacecraft, which hadn’t been designed to land on an asteroid but was successfully eased onto the surface of Eros, where it operated for a very short time.

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It looks like the Moon!

9:03 am

craters on Ceres

Cool image time! Dawn has now swooped down to 3,200 miles, and provided a very nice image of the cratered surface of Ceres. Though it does appear to resemble the Moon, there are some differences that come to mind if you take a close look at the full resolution image. The surface appears smoother. All of the craters appear worn or eroded or less rugged. Also, there are no mountains. The terrain resembles the Moon’s lowlands or maria, but more so.

Note that the region in this picture is tantalizingly close to the double bright spot, but does not include it. Because Dawn is still easing its way into its first survey orbit of 2,700 miles elevation, it only takes pictures when it stops firing its ion engine, which it is doing almost all the time to get where it wants to be. Thus, they apparently only had time for this image.

The spacecraft enters its mapping orbit on June 3. Expect some cool images, including the first good images of the double bright spots, shortly thereafter.

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New Horizons spots all of Pluto’s 5 known moons

7:46 am

New Horizons has now been able to image all of Pluto’s known moons.

Pluto’s five known satellites are Charon, Hydra, Nix, Kerberos and Styx. At 648 miles (1,043 km) in diameter, Charon is nearly half as wide as Pluto itself, but the other four moons are minuscule. Kerberos and Styx, for example, are thought to be just 4 to 13 miles (7 to 21 km) and 6 to 20 miles (10 to 32 km) wide, respectively.

That the spacecraft has been able to spot them all this soon bodes well for what it will see when if flies past Pluto in July.

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New images of Dawn’s double bright spot

8:42 am

The double spot on Ceres

Cool image time! Dawn has released a new animation made from images taken in early May, showing more details of the dwarf planet’s double bright spot.

As they note at the link, the double spot is now “revealed to be composed of many smaller spots.” As they also add, “Their exact nature remains unknown.”

Dawn’s engineers are now beginning to ease the spacecraft down to its survey orbit, about 2,700 miles above the surface.

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Aerojet Rocketdyne faces the possible loss of most of its business

5:41 pm

In the heat of competition: Because of a combination of increased competition, launch failures, political decisions, and quality control questions, the rocket company Aerojet Rocketdyne could lose almost all of its rocket customers in the next few years.

Link fixed! (Once again caused by trying to post while sitting in the passenger seat of the car and typing on a tiny tablet.)

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New studies struggle to explain the origin of the Moon

10:03 am

The uncertainty of science: Three new studies on the mystery of the origin of the Moon all appear to better confirm the theory that it was created when the Earth collided with a Mars-sized planet.

It is important to be aware of the uncertainties here. All these studies were done to try to address problems with the impact theory, and though they kind of answer the questions, they leave behind some important doubts.

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ALMA captures the rotation of the large asteroid Juno

8:52 am

The large ground-based telescope ALMA has captured a series of images of the large asteroid Juno, allowing scientists to estimate its rotation and overall shape.

Linked together into a brief animation, these high-resolution images show the asteroid rotating through space as it shines in millimeter-wavelength light. “In contrast to optical telescopes, which capture the reflected light from the Sun, the new ALMA images show the actual millimeter-wavelength light emitted by the asteroid,” said Todd Hunter, an astronomer with the National Radio Astronomy Observatory (NRAO) in Charlottesville, Va.

…The complete ALMA observation, which includes 10 separate images, documents about 60 percent of one rotation of the asteroid. It was conducted over the course of four hours on 19 October 2014 when Juno was approximately 295 million kilometers from Earth. In these images, the asteroid’s axis of rotation is tilted away from the Earth, revealing its southern hemisphere most prominently.

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Dawn’s chief engineer gives us a detailed update

9:00 am

Link here. Chief engineer Marc Rayman loves to write about Dawn, and his posts on the Dawn blog are probably the most information-packed of any spacecraft blog I have ever read. Key quote this time:

Dawn’s extensive photographic coverage of the sunlit terrain in early May will include these bright spots. They will not be in view, however, when Dawn spies the thin crescent of Ceres in its next optical navigation session, scheduled for April 10.

The orientation of the spacecraft and asteroid now are such that there is no point taking pictures, as most of the asteroid is in darkness.

Read it all, however. He gives a masterful overview of what is going to happen in the coming months.

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NASA has decided to grab an asteroid rock rather than bag an asteroid

10:43 pm

Rather than try to bag an entire small asteroid with an unmanned probe and bring that back to Earth, NASA has decided to send an unmanned probe into orbit around an asteroid and use it to grab one of the asteroid’s boulders.

The $1.25 billion mission, which is planned to launch in December 2020, would send a robotic spacecraft for a rendezvous with an asteroid in 2022. After touching down on the asteroid’s surface, the spacecraft would snatch a boulder several meters across. The spacecraft would then orbit the asteroid for up to 400 days, testing out an idea for defending Earth from a catastrophic asteroid impact: using the spacecraft’s own gravitational field to subtly alter the asteroid’s orbit. Next, the spacecraft would bring the snatched rock back to Earth’s vicinity in 2025. Finally, as part of preparations for a possible mission to Mars, astronauts would visit and examine the rock for some 25 days, using the planned Orion spacecraft to make the trip.

From both a science perspective as well as a manned space perspective, the unmanned part of this plan is a very good idea. Whether it will get funded depends upon Congress, since its roots go back to President Obama’s April 2010 commitment to send astronauts to an asteroid by 2025. Such a commitment was never really realistic, so it has devolved to capturing a rock and sending astronauts to visit it, thus meeting Obama’s commitment in a Potemkin Village sort of way.

Much better to bring the rock back to Earth orbit where it can be captured and brought to ISS by any number of vehicles and studied there. Whether Congress will fund this in the manner proposed in order to help Obama meet his commitment however remains very doubtful.

Posted from Santa Barbara, California.

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Water ice volcanoes on Ceres

2:12 pm

Data collected by Dawn since it entered orbit around Ceres on March 6 now strongly suggests that the bright spots on the surface are produced by venting water,

Andreas Nathues, principal investigator for Dawn’s framing camera, says the feature has spectral characteristics that are consistent with ice. Intriguingly, the brightness can be seen even when the spacecraft is looking on edge at the crater rim, suggesting that the feature may be outgassing water vapor above the rim and into space. “Ceres seems to be indeed active,” he says. The feature brightens through the course of the day, and then shuts down at night. Nathues says the behavior is similar to that of comets.

More here. By mid-April Dawn should finally settle this with high resolution images.

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