Posted on by Ken Kremer

Dawn’s Vestan Endeavour Exceptionally Exciting near End of Year-Long Super Science Survey

Image Caption: Divalia Fossa equatorial trough at Vesta pictured in side by side images showing apparent brightness and topography. The trough encircles most of Vesta and is located just south of the equator. It is about 10 kilometers (6 miles) wide. Rubria and Occia craters straddle Divalia Fossa. The image was snapped on Oct 16, 2011 from an altitude of 700 km (435 mi) from the HAMO mapping orbit. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA

“NASA’s Dawn mission to Asteroid Vesta is going exceptionally well”, Dr. Marc Rayman, the mission’s Chief Engineer, told Universe Today in an exclusive interview as the revolutionary spacecraft nears the end of its more than 1 year long super science survey orbiting the giant space rock.

“The Dawn mission is not only going better than we had expected but even better than we had hoped.”

Dawn is Earth’s first mission ever to orbit and explore Vesta up close.

“We have acquired so much more data than we had planned even in late 2011! We have conducted a tremendous exploration of Vesta – the second most massive body between Mars and Jupiter, a giant of the main asteroid belt.”

“Now we are in our second high altitude mapping orbit (HAMO2), which is the final intensive campaign of the Vesta mission,” Rayman told me.

Image Caption: Dawn Orbiting Vesta above the “Snowman” craters. This artist’s concept shows NASA’s Dawn spacecraft orbiting the giant asteroid Vesta above the Snowman craters. The depiction of Vesta is based on images obtained by Dawn’s framing cameras. Dawn is an international collaboration of the US, Germany and Italy. Credit: NASA/JPL-Caltech

Indeed Dawn’s science and maneuvering endeavour’s at Vesta have proceeded so flawlessly that NASA has granted the science team a bonus of 40 days additional time in orbit split between the lower and higher science orbits known as LAMO and HAMO or the Low Altitude Mapping Orbit and the High Altitude Mapping Orbit respectively.

“Our original Vesta departure date was July 17, and now it is about August 26.” Rayman explained.

The bonus time at LAMO has already been completed. Now the team is about to begin the bonus time at HAMO – consisting of two additional mapping cycles beyond the four originally planned.

Each mapping cycle in HAMO2 consists of 10 orbits. Each orbit is about 12.5 hours.

“On July 14, we will complete mapping cycle 4 and begin 5 (of 6). On July 25 we will leave HAMO2 and escape from orbit on August 26. We will stop thrusting several times before escape to take more neat pictures, mostly of the northern hemisphere,” Rayman told me.

“As Dawn revolves, Vesta rotates on its axis beneath it, turning once every 5.3 hours.”

When Dawn arrived in orbit at Vesta in July 2011 the northern polar region was in darkness as the southern hemisphere basked in summer’s glow. Now as Dawn departs Vesta in August, virtually all of the previously unseen and unphotographed northern polar region is illuminated and will be mapped in exquisite detail.

Coincidentally on July 13/14 as HAMO2 Cycle 4 ends, I’ll be presenting a free public lecture about Dawn and NASA’s Planetary and Human Spaceflight programs at the Adirondack Public Observatory.

Image Caption: Asteroid Vesta and Mysterious Equatorial Grooves – from Dawn Orbiter. This full view of the giant asteroid Vesta was taken by NASA’s Dawn spacecraft on July 24, 2011, at a distance of 3,200 miles (5,200 kilometers). This view shows impact craters of various sizes and mysterious grooves parallel to the equator. The resolution of this image is about 500 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Why has Dawn been granted an extended mission ?

“Dawn has gone so well that we had consumed not even one day of our 40 days of operations margin,” Rayman stated .

“That allowed us to spend more time in LAMO. We had had some unexpected events to be sure, but we managed to deal with all of them so expeditiously that the entire margin remained intact. Then we received the (entirely unrelated) 40 day extension, which allowed us to leave Vesta later. That came about because of our being able to shorten the flight from Vesta to Ceres, so we could still reach Ceres on schedule in 2015.”

“That 40 days allowed us to spend still ~ 30 more days in LAMO and increase HAMO2 by 10 days to a total of six cycles. We got still more time by finding ways to make the trip from HAMO2 to escape a little more efficiently, and that’s what allowed HAMO2 to be even longer, with the additional eight days of VIR-only observations I described in my most recent Dawn Journal.”

“The summary is that every investigation has been more productive than we could have imagined, and because the exploration of Vesta has gone so well, we have been able to apply our unused margin to get even more out of the mission. It is very very gratifying and exciting.”

So we have a few more weeks to enjoy the wondrous sights of Vesta before Dawn fires up her revolutionary ion thrusters to escape the gravitational tug of Vesta and head off to the dwarf planet Ceres, the largest asteroid in the main belt of our Solar System – and which some have speculated may hold vast caches of water and perhaps even liquid oceans suitable for sustaining life.

Ken Kremer

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July 13/14: Free Public Lectures about NASA’s Mars, Vesta and Planetary Exploration, the Space Shuttle, SpaceX , Orion and more by Ken Kremer at the Adirondack Public Observatory in Tupper Lake, NY.

Posted on by John Williams

Oldest Impact Crater on Earth Discovered in Greenland

Artistic expression of large meteorite impact
An artistic expression of how a large meteorite impact into the sea might have looked in the first second of the impacting. We do not know if the area that was hit was actually covered by water or if there was just a sea nearby. Source: Carsten Egestal Thuesen, GEUS

With shifting continents, rain, and wind, finding traces of ancient impact craters on Earth has been, literally, astronomically low. Now, an international team of scientists say they have found a massive impact crater in Greenland a billion years older than other known asteroid impact on Earth.

Scientists found the remains of the giant 100-kilometer (62 mile) wide crater near the Maniitsoq region of West Greenland and they believe it’s three billion years old. The largest and previously oldest known crater is the 300 kilometer-wide Vredefort crater in South Africa. Tipped on its side, the edges of the Maniitsoq crater would extend from the surface of the Earth to the edge of space.


“This single discovery means that we can study the effects of cratering on the Earth nearly a billion years further back in time than was possible before,” according to Dr. Iain McDonald of the School of Earth and Ocean Sciences at Cardiff University, who was part of the team.

Finding the crater wasn’t an easy task. Today, the Moon still shows marks of the massive bombardment that took place between three and four billion years ago. The early Earth, with its greater gravitational attraction, would have experienced even more collisions. But the land around Maniitsoq has been eroded over the eons to expose crust that originally was 25 kilometers (16 miles) below the surface. Effects of the immense shockwave produced on impact penetrated deep into the crust and remain visible.

Evidence at that depth had never been observed before, says McDonald. “The process was rather like a Sherlock Holmes story,” said McDonald. “We eliminated the impossible in terms of any conventional terrestrial processes, and were left with a giant impact as the only explanation for all of the facts.”

Only about 180 impact craters have been discovered on Earth. Around 30 percent of them contain important natural resources, including nickel, gold, oil and natural gas. It was during an exploration of natural resources that evidence for the crater was discovered. “It has taken us nearly three years to convince our peers in the scientific community,” said McDonald. “But the mining industry was far more receptive. A Canadian exploration company has been using the impact model to explore for deposits of nickel and platinum metals at Maniitsoq since the autumn of 2011.”

The international team, led by Adam Garde, a senior research scientist at the Geological Survey of Denmark and Greenland, or GEUS, contains members from Cardiff, Lund University in Sweden, and the Institute of Planetary Science in Moscow. Their work was recently published in the jounal Earth and Planetary Science Letters.

Image caption: An artistic expression of how a large meteorite impact into the sea might have looked in the first second of the impacting. We do not know if the area that was hit was actually covered by water or if there was just a sea nearby. Source: Carsten Egestal Thuesen, GEUS

Map caption: Black circle on map shows the location of the meteorite impact structure near the town Maniitsoq in Greenland.

Read more about the Maniitsoq structure.

Posted on by Nancy Atkinson

Recent Earth-Passing Asteroid is Much Bigger Than Originally Estimated

An asteroid that recently passed by Earth is about twice as large as originally estimated, and it would have had serious global consequences if it had impacted Earth. Asteroid 2012 LZ1 was only discovered on June 10, 2012 by Rob McNaught at the Siding Spring Observatory in Australia. This Near Earth Object was thought to be fairly large, 502 meters (1,650 feet) wide, and quite bright. But astronomers using the planetary radar system at Arecibo Observatory were able to better determine the asteroid’s size, rotation rate and shape and found it to be about 1 kilometer (0.6 miles) wide and actually quite dark.

Scientists consider a kilometer-wide asteroid is at the size threshold that could set off an extinction-level event if it were to hit Earth.

“This object turned out to be quite a bit bigger than we expected, said Dr. Ellen Howell from Arecibo, “which shows how important radar observations can be, because we’re still learning a lot about the population of asteroids.”

2012 LZ1 sneaked by our planet at about 5.3 million km (3.35 million) miles away, or about 14 times the distance between Earth and the Moon on June 14, and it won’t be back in Earth’s vicinity again until June 12th, 2053, and then will be about 3 times as distant.
The Arecibo astronomers have determined it won’t be a threat to Earth for at least 750 years.

“The sensitivity of our radar has permitted us to measure this asteroid’s properties and determine that it will not impact the Earth at least in the next 750 years,” said Dr. Mike Nolan, Director of Planetary Radar Sciences at the Arecibo Observatory.

Several amateur astronomers were able to image 2012 LZ1, and the original thinking was that it was very bright. Instead, the new size determination suggests that 2012 LZ1 must be quite dark, reflecting only 2-4% of the light that hits it.

This is another reminder that we don’t know everything about all the potential asteroid threats that are out there, and more searches need to be done to find and track as many of the near Earth asteroid population as possible. Asteroid 2012 LZ1 has been classified as a Potentially Hazardous Asteroid, which are asteroids larger than approximately 100 meters that can come closer to our planet than 0.05 AU (7.4 million km, 4.65 million miles). As of now, none of the known PHAs is on a collision course with our planet, but both amateur and professional astronomers are finding new ones all the time, sometimes with just a few hours’ notice of a close approach.

Lead image caption: Asteroid 2012 LZ1 as seen by the Haleakala-Faulkes Telescope North on June 13, 2012. Credit: Nick Howes, Ernesto Guido & Giovanni Sostero.

Source: Arecibo Observatory via SpaceRef.

Posted on by Nancy Atkinson

Astronomers View Asteroid 2012 LZ1’s Bright Flyby

As reported, asteroid 2012 LZ1 came about 5.3 million km (3.3 million miles) from planet Earth on its closest approach on June 14th, 2012. The fairly big and unusually bright space rock is about 502 meters (1,650 feet) wide. The Remanzacco Observatory crew of Nick Howes, Ernesto Guido & Giovanni Sostero captured this imagery of the pass.

Ian Musgrave in Australia also took some imagery of the pass:

Asteroid 2012 LZ1 imaged by Ian Musgrave with the iTelescope T16. Click for larger view of the image.

According to a little research by David Dickinson (@Astroguyz on Twitter) by looking at ESA’s NEODYS-2 website, this rock won’t be back in Earth’s vicinity again until June 12th, 2053, and will be about 3 times as distant.

There was no danger this asteroid would impact Earth at the distance it passed, and it appears it won’t be a problem in the future. But it has been classified as a Potentially Hazardous Asteroid. PHAs are asteroids larger than approximately 100 meters that can come closer to our planet than 0.05 AU (7.4 million km, 4.65 million miles). None of the known PHAs is on a collision course with our planet, although, as the Remanzacco team pointed out, astronomers are finding new ones all the time.

See the Minor Planet Center for more details on this object.

Posted on by Jason Major

Astronomers Measure Sunlight’s Shove

The physical force of sunlight on a moving asteroid has been measured by NASA scientists, providing information on how to better plot these Earth-passing worlds’ future paths.

First proposed by a 19-century Russian engineer, the Yarkovsky effect is the result of an object in space absorbing radiation from the Sun and emitting it as heat, thus creating a slight-but-measurable change in its movement (thanks to Newton’s first law of motion.)

By observing the 1999, 2005 and 2011 close passes of asteroid 1999 RQ36 with the Arecibo and Goldstone radar telescopes, astronomers were able to determine how much the trajectory of the half-kilometer-wide asteroid had changed.

The researchers’ findings revealed that RQ36 shifted by 160 km – about 100 miles – over the course of those 12 years. That deviation is attributed to the Yarkovsky effect. A miniscule force in and of itself, over time it has the ability to move entire worlds (albeit relatively small ones.)

“The Yarkovsky force on 1999 RQ36 at its peak, when the asteroid is nearest the Sun, is only about a half ounce — about the weight of three grapes on Earth,” said Steven Chesley of NASA’s Jet Propulsion Laboratory in Pasadena “Meanwhile, the mass of the asteroid is estimated to be about 68 million tons. You need extremely precise measurements over a fairly long time span to see something so slight acting on something so huge.”

Using measurements of the distance between the Arecibo Observatory in Puerto Rico and RQ36 during its latest pass in 2011 – a feat that was compared by team leader Michael Nolan to “measuring the distance between New York City and Los Angeles to an accuracy of two inches” – Chesley and his team were able to calculate all the asteroid’s near-Earth approaches closer than 7.5 million km (4.6 million miles) from the years 1654 to 2135. 11 such passes were found.

In addition, observation of 1999 RQ36 with NASA’s Spitzer Space Telescope found it to have about the same density as water – that’s light, for an asteroid.

Most likely, RQ36 is a “rubble-pile” form of asteroid, composed of a conglomeration of individual chunks of material held together by gravity.

These findings will be used by NASA scientists to help fine-tune the upcoming OSIRIS-REx mission, which is scheduled to launch in 2016 to rendezvous with 1999 RQ36 and return samples to Earth in 2023. Being a loose collection of rocks is expected to aid in the spacecraft’s sample retrieval process.

The findings were presented on May 19 at the Asteroids, Comets and Meteors 2012 meeting in Niigata, Japan. Read more here.

(Top image: series of radar images of asteroid 1999 RQ36 were obtained by NASA’s Deep Space Network antenna in Goldstone, Calif. on Sept 23, 1999. Credit: NASA/JPL-Caltech)

Posted on by Nancy Atkinson

Big and Bright Asteroid to Pass by Earth June 14

An unusually large and bright near-Earth asteroid was recently discovered and it will make its closest approach to Earth on June 14 at about 23:10 UTC. The object is so bright, the Slooh Observatory will attempt to have a live webcast showing the object sneaking past Earth at about 5.3 million km (3.35 million) miles away, or about 14 times the distance between Earth and the Moon. The asteroid, 2012 LZ1 was discovered by Rob McNaught and colleagues on 2012 June 10/11, and is about 502 meters (1,650 feet) wide.

The team of Nick Howes, Ernesto Guido and Giovanni Sostero from the Remanzacco Observatory took this image of 2012 LZ1 on June 13. They also have an animation of the object here.

There’s no danger this asteroid will impact Earth, but it has been classified as a Potentially Hazardous Asteroid. PHAs are asteroids larger than approximately 100 meters that can come closer to our planet than 0.05 AU (7.4 million km, 4.65 million miles). None of the known PHAs is on a collision course with our planet, although, as the Remanzacco team pointed out, astronomers are finding new ones all the time.

The Slooh Observatory will use a telescope on the Canary Islands and webcast the footage beginning at 00:00 UTC on Friday (8:00 p.m. EDT Thursday), and the link to the webcast is http://events.slooh.com/. Discoverer Rob McNaught will be joining the webcast for commentary. McNaught made the discovery using the Uppsala Schmidt telescope at Siding Spring Observatory in Australia.

2012 LZ1 is just a bit smaller than asteroid 2005 YU55 (502 meters), which made a very close flyby of Earth in November, 2011 at just 32,5087km (202,000 miles) away.

Want to try and see this asteroid for yourself? Check out the Minor Planet Center’s ephemeris of this object, and for reference, it will be passing near NGC 6822 (Barnard’s Galaxy) in the constellation Sagittarius at its time of closest approach.

Sources: Remanzacco Observatory, iTelescope.net

Posted on by Nancy Atkinson

Vesta’s Amazing Technicolor Surface

A brand new 3-D video map from the Dawn mission provides a unique view of the varied surface of the giant asteroid Vesta. The animation drapes high-resolution false color images over a 3-D model of the Vesta terrain constructed from Dawn’s observations. This visualization enables a detailed view of the variation in the material properties of Vesta in the context of its topography.
Continue reading “Vesta’s Amazing Technicolor Surface”

Posted on by Jon Voisey

Earth Threatened By Glowing Green Asteroid?

Killer asteroid coming for the Earth?
Killer asteroid coming for the Earth?

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The Daily Mail is reporting that a youtube user has found a strange object while poking around in Google Sky. It looks suspiciously like a glowing green asteroid and he claims it’s heading right for us. But before we call in the experts, let’s do a little bit of critical analysis on our own.

First off, the image raises alarm bells because of the apparent size of the object. Without knowing how far away it may be, it’s hard to say how large it would actually be, but we can put some limits on it. I looked up the region on Aladin and the angular distance between the two stars just to the upper right of the object is 1 arc minute. The object seems to be about that size, so we can use that as a baseline.

Assuming that the object was somewhere in the vicinity of Pluto (roughly 6 billion km), doing a bit of quick geometry means the object would be somewhere around 580,000 km. To put that in context, that’s about 40% the diameter of the Sun. If that were the case, this wouldn’t be an asteroid, it would be a small star. The funny thing about stars is that they tend to be somewhat bright and a lot more round. So that rules out that extreme.

But what if it were very close? At the distance of the moon, that would mean the object would be about 300 km in diameter which would make this thing slightly smaller than the largest asteroid, Ceres. However, this raises another issue: With that much mass, the object should still be pretty round. Additionally, with such a size and distance, it would be very bright. And it’s not.

2011 MD on Monday, June 27, 2011 at 09:30 UTC with RGB filter. Credit: Ernesto Guido, Nick Howes and Giovanni Sostero at the Faulkes Telescope South.
Even closer we run into additional issues. Astronomical images aren’t taken as a single color image. Images like this are taken in 3 filters (RGB) and then combined to make a color image. If the object is nearby, it moves from image to image, showing up in the final image in 3 places, each as a different color. For example, here’s an image of 2011 MD illustrating the effect. Given the object in question doesn’t have this tri-color separation going on, it can’t be nearby.

So this has pretty much ruled out anything anywhere in our solar system. If it’s close, it should have color issues and be bright. If it’s far, it’s too massive to have been missed. Outside of our solar system and it wouldn’t have any apparent motion and should be visible in other images. And it’s not.

In fact, searching the various databases from which Google Sky draws its data (SDSS, DSS, HST, IRAS, and WMAP), the killer asteroid doesn’t appear at all. Thus, it would seem that this object is nothing more than a technical glitch introduced by Google’s stitching together of images. Sorry conspiracy theorists. No Planet X or Nibiru out there this time!

Posted on by Nancy Atkinson

Video: Tiny Asteroid 2012 KT42 Crossing The Sky

2012 KT42 at closest approach. Credit: Peter Lake

A few hours ago, asteroid 2012 KT42 passed by Earth at distance of a mere 14,440 kilometers (8,950 miles), the 6th closest pass on record. This is almost three times closer than geosynchronous satellites. Alex Gibbs from the Catalina Sky Survey, the discoverer of this asteroid, created this video of 2012 KT42 during its closest approach to Earth. Don’t panic, Gibbs says, as the video shows the asteroid moving at 2,000 times the actual speed. However, the asteroid was zooming along at 17km/sec (38,000 mph). Each image is a 3 second exposure, during which the object moved, creating a trail. The images were taken on May 29, 2012 between 4:30 and 6:55 UT, the latter being 6 minutes before closest approach. This asteroid was less than 10 meters across, so was far too small to make it through our atmosphere intact, even if it did intersect directly with Earth’s path. Gibbs said the asteroid was a little brighter than expected, but otherwise lived up to its predicted pass distance and size.

Other astrophotographers also got images of 2012 KT42’s close pass. Peter Lake has this 20-second image, very close to the time of closest approach:

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Lake said he actually took 15 images via a robotic telescope, of which only three had the asteroid in them. “That’s how fast it was going,” he said.

(Video Courtesy Alex R. Gibbs, Catalina Sky Survey, University of Arizona, NASA Near-Earth Object Program.)

Posted on by Nancy Atkinson

Newly Found Asteroid Buzzes Earth

Discovery images of asteroid KT42. Credit: Catalina Sky Survey/Mt. Lemmon Observatory

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A newly found space rock will give Earth a close shave on May 29, passing by at a distance of just 14,440 kilometers (8,950 miles). That distance puts the small asteroid, named 2012 KT42, in the top ten list of closest asteroid approaches. In fact, this is the sixth closest approach to date. The close pass will occur at about 07:00 UTC (03:00 EDT, midnight PDT in the US) on May 29. 2012 KT42 is estimated to be between 3-10 meters in size, and while there is no possibility this asteroid will hit Earth, even if it did, it would surely burn up in the atmosphere.

The sequence of images above were sent to us by Alex Gibbs from the Catalina Sky Survey, who made the discovery of 2012 KT42 with the 1.5 meter telescope on Mt. Lemmon, Arizona on May 28. Gibbs also discovered a similar sized asteroid earlier this year, 2012 BX34, and shared with Universe Today the behind the scenes activities in the discovery of a near-Earth asteroid.

This asteroid closely followed another close pass by a different asteroid, 2012 KP24, which passed by Earth on May 28 at a distance of about 51,000 kilometers (32,000 miles). This rock was bigger, about 25 meters (80 feet) across.

Below is an animation of images of 2012 KT42 taken by Ernesto Guido, Nick Howes and Giovanni Sostero from the Remanzacco Observatory.

An animation showing the motion of 2012 KT42. Each frame is a 5-second exposure through a 2.0-m telescope. Credit: Ernesto Guido, Nick Howes and Giovanni Sostero from the Remanzacco Observatory.

The team said that at the time they took the images on May 28, 2012 KT42 was moving at about ~3.63 “/min and its magnitude was ~17.5. The images were take with the Siding Spring-Faulkes Telescope South through a 2.0-m f/10.0 Ritchey-Chretien telescope.

An interesting note pointed out by the Remanzacco team is that on May 29 at about 10:10 UT, 2012 KT42 will transit across the face of the Sun, and this could be seen from Africa, the Middle East, Asia. But it will be hard to see, if the diameter is about 5m, then the object would only appear about 0.006 of a degree against the solar disk.

In our article about Gibbs’ earlier discovery, he noted that when astronomers look through telescopes, asteroids don’t look much different from stars – they are just points of light. But asteroids are points of light which are moving; however they are moving slow enough that to detect the motion, astronomers take a series of images, usually four images spaced 10-12 minutes apart.

Then, the observers run specialized software to examine their images for any star-like objects that are moving from one image to the next. The software removes any candidates that correspond to known objects or main-belt asteroids. Gibbs said the software has a low detection threshold to avoid missing anything, so the observer looks over what the software found and determines which are real. The remaining objects that the software determines could be interesting are then sent in to the Minor Planet Center (MPC) at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, for the team or others to follow up.

Thanks to Alex Gibbs and the Remanzacco team for sharing their images.

You can see more info about 2012 KT42 at JPL’s Small Body Database website, or at the Minor Planet Center.