Posted on by Ken Kremer

Curiosity Mars Rover Eats 1st Sample of Gray Rocky Powder

NASA's Mars rover Curiosity took this image of Curiosity's sample-processing and delivery tool just after the tool delivered a portion of powdered rock into the rover's Sample Analysis at Mars (SAM) instrument. This Collection and Handling for In-situ Martian Rock Analysis (CHIMRA) tool delivered portions of the first sample ever acquired from the interior of a rock on Mars into both SAM and the rover's Chemistry and Mineralogy (CheMin) instrument. Credit: NASA/JPL-Caltech/MSSS

NASA’s Curiosity rover has eaten the 1st ever samples of gray rocky powder cored from the interior of a Martian rock.

The robotic arm delivered aspirin sized samples of the pulverized powder to the rover’s Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) instruments this past weekend on Feb. 22 and 23, or Sols 195 and 196 respectively.

Both of Curiosity’s chemistry labs have already begun analyzing the samples – but don’t expect results anytime soon because of the complexity of the operation involved.

“Analysis has begun and could take weeks,’ NASA JPL spokesman Guy Webster told Universe Today.

The samples were collected from the rover’s 1st drilling site known as ‘John Klein’ – comprised of a red colored slab of flat, fine-grained, sedimentary bedrock shot through with mineral veins of Calcium Sulfate that formed in water.

“Data from the instruments have confirmed the deliveries,” said Curiosity Mission Manager Jennifer Trosper of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

On Feb. 8, 2013 (mission Sol 182), Curiosity used the rotary-percussion drill mounted on the tool turret at the end of the 7 foot (2.1 meter) long robotic arm to bore a circular hole about 0.63 inch (16 mm) wide and about 2.5 inches (64 mm) deep into ‘John Klein’ that produced a slurry of gray tailings

Curiosity accomplished Historic 1st drilling into Martian rock at John Klein outcrop on Feb 8, 2013 (Sol 182), shown in this context mosaic view of the Yellowknife Bay basin taken on Jan. 26 (Sol 169) where the robot is currently working. The robotic arm is pressing down on the surface at John Klein outcrop of veined hydrated minerals - dramatically back dropped with her ultimate destination; Mount Sharp. Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo
Curiosity accomplished Historic 1st drilling into Martian rock at John Klein outcrop on Feb 8, 2013 (Sol 182), shown in this context mosaic view of the Yellowknife Bay basin taken on Jan. 26 (Sol 169) where the robot is currently working. The robotic arm is pressing down on the surface at John Klein outcrop of veined hydrated minerals – dramatically back dropped with her ultimate destination; Mount Sharp. Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo

The gray colored tailings give a completely fresh insight into Mars that offers a stark contrast to the prevailing views of reddish-orange rusty, oxidized dust.

The eventual results from SAM and CheMin may give clues about what exactly does the color change mean. One theory is that it might be related to different oxidations states of iron that could potentially inform us about the habitability of Mars insides the rover’s Gale Crater landing site.

“The rock drilling capability is a significant advancement. It allows us to go beyond the surface layer of the rock, unlocking a time capsule of evidence about the state of Mars going back 3 or 4 Billion years,” said Louise Jandura of JPL and Curiosity’s chief engineer for the sampling system.

Additional portions of the first John Klein sample could be delivered to SAM and CheMin if the results warrant. The state-of-the-art instruments are testing the gray powder to elucidate the chemical composition and search for simple and complex organic molecules based on carbon, which are the building blocks of life as we know it.

Curiosity’s Mastcam camera snapped this photo mosaic of 1st drill holes into Martian rock at John Klein outcrop inside Yellowknife Bay basin where the robot is currently working. Notice the gray powdery tailings from the rocks interior. Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo
Curiosity’s Mastcam camera snapped this photo mosaic of 1st drill holes into Martian rock at John Klein outcrop inside Yellowknife Bay basin where the robot is currently working. Notice the gray powdery tailings from the rocks interior. Credit: NASA/JPL-Caltech/MSSS/Ken Kremer/Marco Di Lorenzo

The Curiosity science team believes that this work area inside Gale Crater called Yellowknife Bay, experienced repeated percolation of flowing liquid water long ago when Mars was warmer and wetter – and therefore was potentially more hospitable to the possible evolution of life.

Curiosity is nearly 7 months into her 2 year long primary mission. So far she has snapped over 45,000 images.

“The mission is discovery driven,” says John Grotzinger, the Curiosity mission’s chief scientist of the California Institute of Technology.

The rover will likely remain in the John Klein area for several more weeks to a month or more to obtain a more complete scientific characterization of the area which has seen repeated episodes of flowing water.

Eventually, the six-wheeled mega rover will set off on a nearly year long trek to her main destination – the sedimentary layers of the lower reaches of the 3 mile (5 km) high mountain named Mount Sharp – some 6 miles (10 km) away.

Ken Kremer

Posted on by Nancy Atkinson

Is a Comet on a Collision Course with Mars?

Simulation of the close approach of C/2013 A1 to Mars in Celestia using info from the Minor Planet Center. Credit: Ian Musgrave/Astroblog.

There is an outside chance that a newly discovered comet might be on a collision course with Mars. Astronomers are still determining the trajectory of the comet, named C/2013 A1 (Siding Spring), but at the very least, it is going to come fairly close to the Red Planet in October of 2014. “Even if it doesn’t impact it will look pretty good from Earth, and spectacular from Mars,” wrote Australian amateur astronomer Ian Musgrave, “probably a magnitude -4 comet as seen from Mars’s surface.”

The comet was discovered in the beginning of 2013 by comet-hunter Robert McNaught at the Siding Spring Observatory in New South Wales, Australia. According to a discussion on the IceInSpace amateur astronomy forum when the discovery was initially made, astronomers at the Catalina Sky Survey in Arizona looked back over their observations to find “prerecovery” images of the comet dating back to Dec. 8, 2012. These observations placed the orbital trajectory of comet C/2013 A1 right through Mars orbit on Oct. 19, 2014.

However, now after 74 days of observations, comet specialist Leonid Elenin notes that current calculations put the closest approach of the comet at a distance of 109,200 km, or 0.00073 AU from Mars in October 2014. That close pass has many wondering if any of the Mars orbiters might be able to acquire high-resolution images of the comet as it passes by.

But as Ian O’Neill from Discovery Space points out, since the comet has only been observed for 74 days (so far), so it’s difficult for astronomers to forecast the comet’s precise location in 20 months time. “Comet C/2013 A1 may fly past at a very safe distance of 0.008 AU (650,000 miles),” Ian wrote, “but to the other extreme, its orbital pass could put Mars directly in its path. At time of Mars close approach (or impact), the comet will be barreling along at a breakneck speed of 35 miles per second (126,000 miles per hour).”

Elenin said that since C/2013 A1 is a hyperbolic comet and moves in a retrograde orbit, its velocity with respect to the planet will be very high, approximately 56 km/s. “With the current estimate of the absolute magnitude of the nucleus M2 = 10.3, which might indicate the diameter up to 50 km, the energy of impact might reach the equivalent of staggering 2×10¹º megatons!”

An impact of this magnitude would leave a crater 500 km across and 2 km deep, Elenin said.

Fragments of Shoemaker-Levy 9 on approach to Jupiter (NASA/HST)
Fragments of Shoemaker-Levy 9 on approach to Jupiter (NASA/HST)

While the massive Comet Shoemaker–Levy 9 (15 km in diameter) that crashed into Jupiter in 1994 was spectacular as seen from Earth orbit by the Hubble Space Telescope, an event like C/2013 A1 slamming into Mars would be off the charts.

Astronomers are certainly keeping an eye on this comet, and they will refine their measurements as more data comes in. You can see the orbital parameters available so far at JPL’s Solar System Dynamics website.

We’ll keep you posted.

Sources: Astroblog, IceInSpace, SpaceObs, Discovery Space

Posted on by David Dickinson

Spotting the Dragon: How to See SpaceX on Approach to the ISS This Weekend

Capture of the Dragon during the October 2012 CRS-1 mission. (Credit: NASA/ISS).

SpaceX’s Dragon spacecraft may be appearing in a backyard sky near you this weekend. Scheduled to launch this Friday on March 1st at 10:10 AM Eastern Standard Time (EST)/15:10 Universal Time (UT), this will be the 3rd resupply flight for the Dragon spacecraft to the International Space Station (ISS).  And the great news is, you may just be able to catch the spacecraft as it chases down the ISS worldwide.

The Space Shuttle and the ISS captured by the author as seen from Northern Maine shortly after undocking in June, 2007. 

Catching a satellite in low Earth orbit is an unforgettable sight. Satellites appear as moving “stars” against the background sky, shining steadily (unless they’re tumbling!) in the sunlight overhead in the dawn or dusk sky. Occasionally, you may catch a flare in brightness as a reflective panel catches the sunlight just right. The Hubble Space Telescope and the Iridium constellation of satellites can flare in this fashion.

At 109 metres in size, the ISS is the largest object ever constructed in orbit and is easily visible to the naked eye. It has an angular diameter of about 50” when directly overhead (about the visual size of Saturn plus rings near opposition). I can just make out a tiny box-like structure with binoculars when it passes overhead. If the orientation of the station and its solar panels is just right, it looks like a tiny luminous Star Wars TIE fighter as viewed through binoculars!

Dragon in the processing hangar at Cape Canaveral. (Credit: NASA/Kim Shiflett).
Dragon in the processing hangar at Cape Canaveral. (Credit: NASA/Kim Shiflett).

But what’s even more amazing is to watch a spacecraft rendezvous with the ISS, as diligent observers may witness this weekend. Your best bet will be to use predictions for ISS passes from your location. Heavens-Above, CALSky and Space Weather all have simple trackers for sky watchers. More advanced observers may want to use an application known as Orbitron which allows you to manually load updated Two-Line Element sets (TLEs) from Celestrak or NORAD’s Space-Track website for use in the field sans Internet connection. Note that Space-Track requires permission to access; they welcome amateur sat-spotters and educators, but they also want to assure that no “rogue entities” are accessing the site! Continue reading “Spotting the Dragon: How to See SpaceX on Approach to the ISS This Weekend”

Posted on by Nancy Atkinson

Astrophotos: The Full Snow Moon

Fishing for walleye on the Bay of Quinte (Lake Ontario) near Belleville, Ontario, when the full Moon appeared through the clouds on the horizon. Credit and copyright: Rick Stankiewicz.

In Native American lore, the full Moon in February is called the Snow Moon, as this time of year usually signals the deepest snows of winter in the now cold northern latitudes in the Northern Hemisphere. This year, the full moon fell on February 25th and here are a few images shared by our readers. Above is a classic view of a winter evening in the north — especially where I used to live in Minnesota, but also where Rick Stankiewicz lives in Ontario, Canada.

“I was fishing for walleye with some friends on the Bay of Quinte (Lake Ontario) near Belleville, Ontario,” Rick wrote, “and I was fortunate to be in an opportune location to see the Moon rising in the eastern sky. “A pale pastel pink disc appeared initially, but as the minutes wore on and the lunar disk rose higher above the horizon it grew brighter and transformed from pink, then red, then orange as it evaded more and more of the earth’s atmosphere along the horizon. What a wonderful sight and this made the whole trip worth the effort. Our fishing party caught one nice fish this trip but the rising of the Snow Moon was the ‘icing on the cake’ for me.”

A beautiful shot too!

See more below:

Planet Moon? A panoramic view from Östersund, Sweden. Credit and copyright: Göran Strand
Planet Moon? A panoramic view from Östersund, Sweden. Credit and copyright: Göran Strand

Here’s a fun panoramic view of the full Moon, which seemingly creates a little snow covered planet with the full Moon in the sky. This was sent in by Göran Strand from Sweden: “I wanted to catch the Moon in a snowy environment,” Göran wrote, “so me and my friend went out on Storsjöns snow-covered ice here in Östersund, Sweden….As a bonus, a light mist came in over the lake just as we arrived.”

The full Snow Moon on 02-25-2013 as seen from Dayton, Ohio USA. Credit and copyright: John Chumack.
The full Snow Moon on 02-25-2013 as seen from
Dayton, Ohio USA. Credit and copyright: John Chumack.

Our pal John Chumack can always be counted on for a great view of the full Moon! You can see more of his images at his Flickr page or his website, Galactic Images.

The Moon partially hidden by tree branches, taken on February 25, 2013. Credit and copyright: Carolyn Postelwait.
The Moon partially hidden by tree branches, taken on February 25, 2013. Credit and copyright: Carolyn Postelwait.
The February 2013 full Moon as seen in Michigan, USA. Credit and copyright: Kevin (Kevin's Stuff on Flickr.)
The February 2013 full Moon as seen in Michigan, USA. Credit and copyright: Kevin (Kevin’s Stuff on Flickr.)
[caption]

[caption id="attachment_100297" align="aligncenter" width="580"]The full Moon as seen in Japan on Feb. 25, 2013. Credit and copyright: Masashi Ito. The full Moon as seen in Japan on Feb. 25, 2013. Credit and copyright: Masashi Ito.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Posted on by Nancy Atkinson

Carnival of Space #290

This week’s Carnival of Space is hosted by Gadi Eidelheit at the Transit of Venus blog.

Click here to read Carnival of Space #290.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

Posted on by Jason Major

One Astronaut’s Kids Get a Valentine’s Day View of Dad’s Office in Orbit

View of Rhode Island from the ISS, captured by Expedition 34 Commander Kevin Ford. Providence is just past the top center edge. (NASA)

It’s a wonderful thing for children to look up to their fathers, but some kids have to look a little further than others — especially when dad is in command of the International Space Station!

Around 6 p.m. EST on February 14, the ISS passed over southern New England, and for a few brief moments the Station was directly above Rhode Island, at 37 miles wide the smallest state in the US. 240 miles up and heading northeast at 17,500 mph, the ISS quickly passed out of sight for anyone watching from the ground, but it was enough time for Heidi and Anthony Ford to get a view of the place where their father Kevin Ford has been living and working since the end of October… and thanks to Brown University’s historic Ladd Observatory and astronomer Robert Horton they got to see the Station up close while talking to their dad on the phone.

“One of the things [Anthony and I] like to do is to pop outside to watch dad fly over, which you can do on occasion when the timing is just right,” Heidi said. “We were looking at the schedule to see when the flyover would be so we could go see him. I remembered that the Ladd was open to the public, so I thought I’d call over there and see if this is something we could visit the Ladd to do.”

Robert Horton, an astronomer with Brown University, was happy to meet Heidi and Anthony at the Ladd for the flyover.

Heidi and Anthony Ford's view of the ISS (Robert Horton/Brown University)
Heidi and Anthony Ford’s view of the ISS (Robert Horton/Brown University)

While the Ladd’s main 12″ telescope doesn’t have the ability to track fast-moving objects like the ISS, Horton had some at home that could. So he set one of them up at the observatory and prepared to track the station during its six-minute pass.

Just before the flyby, Heidi’s phone rang — it was her dad calling from the ISS.

“He told her, ‘I’m over Texas. I’ll be there in a few minutes,’” Horton said later in an interview with Brown reporters. “Sure enough the point of light appeared in the sky and we started to track it. They could look through the eyepiece and actually make out the solar panels while they were talking with him.”

The Brown University-run Ladd Observatory holds free public viewing nights every Tuesday, weather permitting. People line up inside the 122-year-old dome to peer through its recently restored 12″ refracting telescope at objects like the Moon, Jupiter, and Saturn, and local amateur astronomers set up their own ‘scopes on the observatory’s rooftop deck for additional viewing opportunities.

Heidi had told their dad that they’d be watching from Providence as he passed over, and luckily his schedule allowed him to make a phone call during that particular evening’s pass.

NASA astronauts Kevin Ford (foreground) and Tom Marshburn working with the Combustion Integrated Rack (CIR) Multi-user Droplet Combustion Apparatus (MDCA) in the ISS' Destiny laboratory on Jan. 9 (NASA)
NASA astronauts Kevin Ford (foreground) and Tom Marshburn working with the Combustion Integrated Rack (CIR) Multi-user Droplet Combustion Apparatus (MDCA) in the ISS’ Destiny laboratory on Jan. 9 (NASA)

While they had both watched flyovers before, it was the first time either of them had ever seen the ISS through a telescope.

It made for a “very special Valentine’s Day,” Heidi said.

And as for Horton, who had donated the use of his telescope? He got a chance to talk with Commander Ford as well — an experience he’ll likely never forget.

“I can think of a thousand questions to ask him now that I’m not on the phone with him,” Horton said. “But, frankly, I was awestruck at the time.”

Read more on the Brown University news article by Kevin Stacey here. (Excerpts used with permission.)

Ladd Observatory today and after its opening in 1891. (Brown University)
Ladd Observatory today and after its opening in 1891. (Brown University)

Thanks to Jim Hendrickson of Skyscrapers, Inc. for the story alert.

Posted on by Jason Major

New Horizons’ Pluto Stamp is One Step Closer to Becoming a Reality

Concept art for a New Horizons postage stamp. Image Credit: Dan Durda/Southwest Research Institute

A little over a year ago Alan Stern, principal investigator on the New Horizons mission, announced the team’s plans to have a Forever Stamp issued by the US Postal Service commemorating the New Horizons spacecraft along with its targets, Pluto and Charon. Thousands signed the petition, and today the team announced a long-awaited update to all of its supporters: it’s definitely a maybe!

In an email sent out to petition signers as well as on its Facebook page, the New Horizons team noted that the stamp — conceptualized by planetary scientist and artist Dan Durda — has cleared its first major hurdle in the USPS approval process and will be submitted for review and consideration before their Advisory Committee.

Pending that approval, it will then be put on the agenda for the meeting of the Citizens’ Stamp Advisory Committee.

After that point, since no notification is made to the applicant about a stamp’s approval by the Postmaster General until a public announcement is issued it’s likely that we won’t know if there will actually be a New Horizons stamp until the spacecraft is on final approach to Pluto in July 2015. Hopefully the USPS will see the benefit to having a stamp actually ready for purchase by that time and plan accordingly, but one never knows. Until then, cross your fingers and keep an eye out for a Forever Stamp featuring the “First Spacecraft to Explore Pluto!”

“This is a chance for us all to celebrate what American space exploration can achieve though hard work, technical excellence, the spirit of scientific inquiry, and the uniquely human drive to explore.”

– Alan Stern, New Horizons Principal Investigator

USPS Forever Stamps can be used to mail a one-ounce letter regardless of when the stamps are purchased or used and no matter how prices may change in the future. Forever Stamps are always sold at the same price as a regular First-Class Mail stamp. Forever Stamps can be used for international mail, but since all international prices are higher than domestic US prices, additional postage is necessary.

Posted on by Nancy Atkinson

Why Dying Stars Might be a Good Place to Look for Life

A ghostly blue ring is a planetary nebula - hydrogen gas the star ejected as it evolved from a red giant to a white dwarf. Credit: David A. Aguilar (CfA)

We’ve currently found 867 different exoplanets, but have yet to definitely determine if one of those harbors life. How will astronomers make that determination? They’ll look at things such as its composition, orbital properties, atmosphere, and potential chemical interactions. While oxygen is relatively abundant in the Universe, finding it in the atmosphere of a distant planet could point to its habitability because its presence – in large quantities — would signal the likely presence of life.

But where to look first? A new study finds that we could detect oxygen in the atmosphere of a habitable planet orbiting a white dwarf – a star that is in the process of dying — much more easily than for an Earth-like planet orbiting a Sun-like star.

“In the quest for extraterrestrial biological signatures, the first stars we study should be white dwarfs,” said Avi Loeb, theorist at the Harvard-Smithsonian Center for Astrophysics (CfA) and director of the Institute for Theory and Computation.

Loeb and his colleague Dan Maoz from Tel Aviv University estimate that a survey of the 500 closest white dwarfs could spot one or more habitable Earths.

Potential habitable exoplanets, as of Feb. 18, 2013. Credit: The Planetary Habitability Labratory at UPR/Arecibo.
Potential habitable exoplanets, as of Feb. 18, 2013. Credit: The Planetary Habitability Labratory at UPR/Arecibo.

A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. It puffs off its outer layers, leaving behind a hot core which can be about the size of Earth. It slowly cools and fades over time, but it can retain heat long enough to warm a nearby world for billions of years.

Currently, most planets that we’ve found orbit close to their parent star, since astronomers find planets using astrometry by the gravitational influence the planet has on the star, causing it to wobble ever so slightly. Massive planets close to the star have the biggest effect and so are the easiest to detect.

Using the photometry, astronomers see a dip in the amount of light a star gives off when a planet passes in front of the star. Since a white dwarf is about the same size as Earth, an Earth-sized planet would block a large fraction of its light and create an obvious signal. Photometry, or the transit method, has proven the best way to find exoplanets.

A white dwarf is much smaller and fainter than the Sun, and a planet would have to be much closer in to be habitable with liquid water on its surface, so that should make planets around a white dwarf star easier to detect. A habitable planet would circle the white dwarf once every 10 hours at a distance of about a million miles.

More importantly, we can only study the atmospheres of transiting planets. When the white dwarf’s light shines through the ring of air that surrounds the planet’s silhouetted disk, the atmosphere absorbs some starlight. This leaves chemical fingerprints showing whether that air contains water vapor, or even signatures of life, such as oxygen.

But there’s a caveat: Before a star becomes a white dwarf it swells into a red giant, engulfing and destroying any nearby planets. Therefore, a planet would have to arrive in the habitable zone after the star evolved into a white dwarf. Either it would migrate towards the star from a more distant orbit or be a new planet formed from leftover dust and gas.

However, we have yet to find a exoplanet around a white dwarf, even though Loeb and Moaz say the abundance of heavy elements on the surface of white dwarfs suggests that a significant fraction of them have rocky planets.

We need a better eye in the sky to find planets around white dwarfs, say Loeb and Maoz, and the James Webb Space Telescope (JWST), scheduled for launch by the end of this decade, promises to sniff out the gases of these alien worlds.

Loeb and Maoz created a synthetic spectrum, replicating what JWST would see if it examined a habitable planet orbiting a white dwarf. They found that both oxygen and water vapor would be detectable with only a few hours of total observation time.

“JWST offers the best hope of finding an inhabited planet in the near future,” said Maoz.

The James Webb Space Telescope. Credit: NASA
The James Webb Space Telescope. Credit: NASA

Recent research by CfA astronomers Courtney Dressing and David Charbonneau showed that the closest habitable planet is likely to orbit a red dwarf star (a cool, low-mass star undergoing nuclear fusion). Since a red dwarf, although smaller and fainter than the Sun, is much larger and brighter than a white dwarf, its glare would overwhelm the faint signal from an orbiting planet’s atmosphere. JWST would have to observe hundreds of hours of transits to have any hope of analyzing the atmosphere’s composition.

“Although the closest habitable planet might orbit a red dwarf star, the closest one we can easily prove to be life-bearing might orbit a white dwarf,” said Loeb.

Read their paper here.

Source: CfA

Posted on by Nancy Atkinson

Astronomers Calculate Orbit and Origins of Russian Fireball

econstructed orbits for the Chelyabinsk meteoroid. Credit: Jorge Zuluaga and Ignacio Ferrin, University of Antioquia in Medellin, Colombia

Just a week after a huge fireball streaked across the skies of the Chelyabinsk region of Russia, astronomers published a paper that reconstructs the orbit and determines the origins of the space rock that exploded about 14-20 km (8-12.5 miles) above Earth’s surface, producing a shockwave that damaged buildings and broke windows.

Researchers Jorge Zuluaga and Ignacio Ferrin at the University of Antioquia in Medellin, Colombia used a resource not always available in meteorite falls: the numerous dashboard and security cameras that captured the huge fireball. Using the trajectories shown in videos posted on YouTube, the researchers were able to calculate the trajectory of the meteorite as it fell to Earth and use it to reconstruct the orbit in space of the meteoroid before its violent encounter with our planet.

The results are preliminary, Zuluaga told Universe Today, and they are already working on getting more precise results. “We are working hard to produce an updated and more precise reconstruction of the orbit using different pieces of evidence,” he said via email.

But through their calculations, Zuluaga and Ferrin determined the rock originated from the Apollo class of asteroids.

Using triangulation, the researchers used two videos specifically: one from a camera located in the Revolutionary Square in Chelyabinsk and one video recorded in the a nearby city of Korkino, along with the location of a hole in the ice in Lake Chebarkul, 70km west of Chelyabinsk. The hole is thought to have come from the meteorite that fell on February 15.

Zuluaga and Ferrin were inspired to use the videos by Stefen Geens, who writes the Ogle Earth blog and who pointed out that the numerous dashcam and security videos may have gathered data about the trajectory and speed of the meteorite. He used this data and Google Earth to reconstruct the path of the rock as it entered the atmosphere and showed that it matched an image of the trajectory taken by the geostationary Meteosat-9 weather satellite.

But due to variations in time and date stamps on several of the videos — some which differed by several minutes — they decided to choose two videos from different locations that seemed to be the most reliable.

From triangulation, they were able to determine height, speed and position of the meteorite as it fell to Earth.

This video is a virtual exploration of the preliminary orbit computed by Zuluaga & Ferrin

But figuring out the meteroid’s orbit around the Sun was more difficult as well as less precise. They needed six critical parameters, all which they had to estimate from the data using Monte Carlo methods to “calculate the most probable orbital parameters and their dispersion,” they wrote in their paper. Most of the parameters are related to the “brightening point” – where the meteorite becomes bright enough to cast a noticeable shadow in the videos. This helped determine the meteorite’s height, elevation and azimuth at the brightening point as well as the longitude, latitude on the Earth’s surface below and also the velocity of the rock.

“According to our estimations, the Chelyabinski meteor started to brighten up when it was between 32 and 47 km up in the atmosphere,” the team wrote. “The velocity of the body predicted by our analysis was between 13 and 19 km/s (relative to the Earth) which encloses the preferred figure of 18 km/s assumed by other researchers.”

They then used software developed by the US Naval Observatory called NOVAS, the Naval Observatory Vector Astrometry to calculate the likely orbit. They concluded that the Chelyabinsk meteorite is from the Apollo asteroids, a well-known class of rocks that cross Earth’s orbit.

According to The Technology Review blog, astronomers have seen over 240 Apollo asteroids that are larger than 1 km but believe there must be more than 2,000 others that size.

However, astronomers also estimate there might be about 80 million out there that are about same size as the one that fell over Chelyabinsk: about 15 meters (50 feet) in diameter, with a weight of 7,000 metric tons.

In their ongoing calculations, the research team has decided to make future calculations not using Lake Chebarkul as one of their triangulation points.

“We are acquainted with the skepticism that the holes in the icesheet of the lake have been produced artificially,” Zuluaga told Universe Today via email. “However I have also read some reports indicating that pieces of the meteoroid have been found in the area. So, we are working hard to produce an updated and more precise reconstruction of the orbit using different pieces of evidence.”

Many have asked why this space rock was not detected before, and Zuluaga said determining why it was missed is one of the goals of their efforts.

“Regretfully knowing the family at which the asteroid belongs is not enough,” he said. “The question can only be answered having a very precise orbit we can integrate backwards at least 50 years. Once you have an orbit, that orbit can predict the precise position of the body in the sky and then we can look for archive images and see if the asteroid was overlooked. This is our next move!”

Read the team’s paper here.

The video from Revolutionary Square in Chelyabinsk:

Video recorded in Korkino:

Read more about the Apollo class of asteroids here.

Posted on by David Dickinson

Light-travel-time Effect Finds New Astronomical Applications

Io and Jupiter as seen by New Horizons during its 2008 flyby. (Credit: NASA/Johns Hopkins University APL/SWRI).

Sometimes the tried and true methods are still the best, even in observational astronomy. Researchers at the University of Prague demonstrated this recently in a study of the eclipsing binary system V994 Herculis (V994 Her).

Researchers P. Zasche and R. Uhla used a method known as the Light-travel-time Effect to verify that V994 Her is actually a double binary. If that method sounds familiar to any astronomy historians out there, that’s because it was first used by 17th century astronomers to gauge the speed of light.

V994 Her is a rarity in the skies. While many eclipsing binaries are known, V994 Her is one of only six quadruple eclipsing binary stars discovered. An eclipsing binary star is a system where the two stars pass one in front of the other from our line of sight. Although too close to be split visually, eclipsing binaries rise and fall in brightness periodically. One famous example is the star Algol (Beta Persei) in the constellation Perseus. Algol means the “Demon Star” in Arabic, which suggests that its curious nature was known to Arab astronomers in pre-telescopic times.

Continue reading “Light-travel-time Effect Finds New Astronomical Applications”