Crucial data gained from Chelyabinsk meteor fall

News from NASA….

A team of NASA and international scientists for the first time have gathered a detailed understanding of the effects on Earth from a small asteroid impact.

The unprecedented data obtained as the result of the airburst of a meteoroid over the Russian city of Chelyabinsk on Feb. 15, has revolutionized scientists’ understanding of this natural phenomenon.

The Chelyabinsk incident was well observed by citizen cameras and other assets. This factor provided a unique opportunity for researchers to calibrate the event, with implications for the study of near-Earth objects (NEOs) and the development of hazard mitigation strategies for planetary defense. Scientists from nine countries now have established a new benchmark for future asteroid impact modeling.

“Our goal was to understand all circumstances that resulted in the shock wave,” said meteor expert Peter Jenniskens, co-lead author of a report published in the journal Science.

Jenniskens, a meteor astronomer at NASA’s Ames Research Center and the SETI Institute, participated in a field study led by Olga Popova of the Institute for Dynamics of Geospheres of the Russian Academy of Sciences in Moscow in the weeks following the event.

“It was important that we followed up with the many citizens who had firsthand accounts of the event and recorded incredible video while the experience was still fresh in their minds,” said Popova.

By calibrating the video images from the position of the stars in the night sky, Jenniskens and Popova calculated the impact speed of the meteor at 42,500 mph (19 kilometers per second). As the meteor penetrated through the atmosphere, it fragmented into pieces, peaking at 19 miles (30 kilometers) above the surface. At that point the superheated meteor appeared brighter than the sun, even for people 62 miles (100 kilometers) away.

Because of the extreme heat, many pieces of the meteor vaporized before reaching Earth. Scientists believe that between 9,000 to 13,000 pounds (4,000 to 6,000 kilograms) of meteorites fell to the ground. This amount included one fragment weighing approximately 1,400 pounds (650 kilograms). This fragment was recovered from Lake Chebarkul on Oct. 16 by professional divers guided by Ural Federal University researchers in Yekaterinburg, Russia.

NASA researchers participating in the 59-member consortium study suspect the abundance of shock fractures in the rock contributed its breakup in the upper atmosphere. Meteorites made available by Chelyabinsk State University researchers were analyzed to learn about the origin of the shock veins and their physical properties. Shock veins are caused by asteroid collisions. When asteroid collide with each other, heat generated by the impact causes iron and nickel components of the objects to melt. These melts cool into thin masses, forming metal veins – shock veins – in the objects.

“One of these meteorites broke along one of these shock veins when we pressed on it during our analysis,” said Derek Sears, a meteoriticist at Ames.

Mike Zolensky, a cosmochemist at NASA’s Johnson Space Center in Houston, may have found why these shock veins (or shock fractures), were so frail. They contained layers of small iron grains just inside the vein, which had precipitated out of the glassy material when it cooled.

“There are cases where impact melt increases a meteorite’s mechanical strength, but Chelyabinsk was weakened by it,” said Zolensky.

The impact that created the shock veins may have occurred as long ago as 4.4 billion years. This would have been 115 million years after the formation of the solar system, according to the research team, who found the meteorites had experienced a significant impact event at that time.

“Events that long ago affected how the Chelyabinsk meteoroid broke up in the atmosphere, influencing the damaging shockwave,” said Jenniskens.

NASA’s Near-Earth Object Program sponsors research to better understand the origin and nature of NEOs. These essential studies are needed to inform our approach to preparing for the potential discovery and deflection of an object on a collision course with the Earth.

NASA’s recently announced asteroid initiative includes the first mission to capture and relocate an asteroid, as well as a grand challenge to find and characterize all asteroid threats to human population. It represents an unprecedented technological feat that will lead to new scientific discoveries and technological capabilities that will help protect our home planet.

Aside from representing a potential threat, the study of asteroids and comets represent a valuable opportunity to learn more about the origins of our solar system, the source of water on the Earth, and even the origin of organic molecules that lead to the development of life.

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Astounding view from Medina

Photo: Herbig-Haro Region of Pelican Nebula. Image by Joe Golias, all rights reserved.

Herbig-Haro 555 by Joe Golias

Joe Golias is a long-time member of the CAA and owner of Astrozap, maker of telescope dew shields and other accessories. Golias is also an accomplished astro-imager who has shared with us many beautiful pictures of galaxies, star clusters, and nebulas. His most recent image is quite astounding in its detail, beauty, and technique: an area if the “Pelican Nebula” (IC5070) called the Herbig-Haro 555. Here’s Golias’ description of his imaging process:

“I wanted to share one of my first attempts at narrowband imaging.  My target was an area found in the Pelican Nebula IC5070 called the Herbig-Haro 555 region.

Image details:

  • Telescope: Takahashi TOA 150 working at F/7
  • Camera: SBIG STT 8300 Pro
  • Guiding: Custom Zapahashi guide scope with SBIG ST4
  • Mount: Losmandy G11
  • Total exposure: 15 hours, three nights through HA, OIII, SII filters. 20 minute subs each channel.
  • Location: Granger Township, Medina, Ohio.
  • Sky conditions: Waxing Gibbous Moon

This was my first attempt to do any type of “real” imaging from my backyard.” Golias usually images from a personal dark-sky site in Central Ohio.

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Not viewable from Earth

Photo: Image of Saturn from above a polar region.  Credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic

Saturn from Above

High Above Saturn: This portrait, looking down on Saturn and its rings, was created from images obtained by NASA’s Cassini spacecraft on Oct. 10, 2013. It is a view we can never see from Earth. The picture was made by amateur image processor and Cassini fan Gordan Ugarkovic. This image has not been geometrically corrected for shifts in the spacecraft perspective and still has some camera artifacts.The mosaic was created from 12 image footprints with red, blue and green filters from Cassini’s imaging science subsystem. Ugarkovic used full color sets for 11 of the footprints and red and blue images for one footprint.

Image credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic

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Confirmed: Earth’s “Martian meteorites” really are from Mars

PASADENA, Calif. — Examination of the Martian atmosphere by NASA’s Curiosity Mars rover confirms that some meteorites that have dropped to Earth really are from the Red Planet.

A key new measurement of the inert gas argon in Mars’ atmosphere by Curiosity’s laboratory provides the most definitive evidence yet of the origin of Mars meteorites while at the same time providing a way to rule out Martian origin of other meteorites.

The new measurement is a high-precision count of two forms of argon — argon-36 and argon-38 — accomplished by the Sample Analysis at Mars (SAM) instrument inside the rover. These lighter and heavier forms, or isotopes, of argon exist naturally throughout the solar system. On Mars the ratio of light to heavy argon is skewed because much of that planet’s original atmosphere was lost to space. The lighter form of argon was taken away more readily because it rises to the top of the atmosphere more easily and requires less energy to escape. That left the Martian atmosphere relatively enriched in the heavier isotope, argon-38.

Years of past analyses by Earth-bound scientists of gas bubbles trapped inside Martian meteorites had already narrowed the Martian argon ratio to between 3.6 and 4.5 (that is 3.6 to 4.5 atoms of argon-36 to every one of argon-38). Measurements by NASA’s Viking landers in the 1970s put the Martian atmospheric ratio in the range of four to seven. The new SAM direct measurement on Mars now pins down the correct argon ratio at 4.2.

“We really nailed it,” said Sushil Atreya of the University of Michigan, Ann Arbor, lead author of an Oct. 16 paper reporting the finding in Geophysical Research Letters. “This direct reading from Mars settles the case with all Martian meteorites.”

One reason scientists have been so interested in the argon ratio in Martian meteorites is that it was — before Curiosity — the best measure of how much atmosphere Mars has lost since the planet’s wetter, warmer days billions of years ago. Figuring out the planet’s atmospheric loss would enable scientists to better understand how Mars transformed from a once water-rich planet, more like our own, into today’s drier, colder and less-hospitable world.

Had Mars held onto all of its atmosphere and its original argon, its ratio of the gas would be the same as that of the sun and Jupiter. Those bodies have so much gravity that isotopes can’t preferentially escape, so their argon ratio — which is 5.5 — represents that of the primordial solar system.

While argon makes up only a tiny fraction of the gas lost to space from Mars, it is special because it’s a noble gas. That means the gas is inert, not reacting with other elements or compounds, and therefore a more straightforward tracer of the history of the Martian atmosphere.

“Other isotopes measured by SAM on Curiosity also support the loss of atmosphere, but none so directly as argon,” said Atreya. “Argon is the clearest signature of atmospheric loss because it’s chemically inert and does not interact or exchange with the Martian surface or the interior. This was a key measurement that we wanted to carry out on SAM.”

The Curiosity measurements do not directly measure the current rate of atmospheric escape, but NASA’s next mission to Mars, the Mars Atmosphere and Volatile Evolution Mission (MAVEN), is designed to do so. That mission is being prepared at NASA’s Kennedy Space Center in Florida for a launch-opportunity period that begins on Nov. 18.

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October begins with aurora’s glowing showing

Photo: Aurora by Christopher Christie

Aurora borealis of October 2, 2013 photographed by Christopher Christie

A coronal mass ejection (CME) hit Earth’s magnetic field during the early hours of October 2, sparking a geomagnetic storm. In North America, auroras spilled across the Canadian border into more than a dozen northern-tier US states, including Northern Ohio. The CME left the sun on Sept. 30, propelled by an erupting magnetic filament, racing away from the Sun at 2 million MPH.

CAA members David Nuti and Christopher Christie observed the light show from Lake Erie’s southern shoreline and captured some images. Presented here is one we think is pretty spectacular!

Photo Notes: Canon EOS Rebel T3: ISO 800, 12 sec., f/3.5, 18mm, 12:41 AM, October 2, 2013.

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Fireball thrills observers

Published on Sep 28, 2013
Last night, a meteor exploded in the skies above the US midwest. Witnesses report shadows cast upon the ground, unusual sounds, and a swirling contrail marking the aftermath of the blast. A NASA all-sky camera in Hiram, Ohio, recorded the fireball at 11:33 pm EDT: 

”This was a very bright event,” reported Bill Cooke of NASA’s Meteoroid Environment Office. “Flares saturated our meteor cameras, and made determination of the end point (the terminus of the fireball’s flight through the atmosphere) virtually impossible. Judging from the brightness, we are dealing with a meter-class object.”

Data from multiple cameras shows that the meteoroid hit Earth’s atmosphere traveling 51 km/s (114,000 mph) and passed almost directly over Columbus, Ohio. Cooke has prepared a preliminary map of the ground track. According to the American Meteor Society, the fireball was visible from at least 14 US states. The meteor is estimated to have exploded 41 miles directly above Columbus, Ohio.

Members of the CAA, at the club’s Letha House Park observing site near Spencer, Ohio, also saw the event. Observatory Director Jay Reynolds recounted the sight: “[Others] were observing in the parking lot, I was in the observatory reviewing photos I had taken when the observatory grew from darkness to BRIGHT in half a second! [It was] initially white, then green, then FLASH as if someone took a photo. As we looked, Capricorn now had a large glowing scar running 15-20 degrees horizontally across, running through it. The smoke trail was so bright, it too, may have been able to cast a shadow in the first second after it’s flashy birth, slowly fading, taking nearly a minute to disappear.”

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M27 from Arches NP Utah

Photo: M27 Nebula, by Dave Watkins

M27 from Arches National Park, Utah, by Dave Watkins

by Dave Watkins, CAA Member

We headed out west (driving) to California and Utah a couple of weeks ago.  We managed one clear night out of seven nights total for exceptional viewing.  Unusual for out west as it’s usually clear most of the time.  But they have been experiencing torrential rains and major flooding lately.  Portions of Zion and Arches were closed before we got there, but opened while we were there, only to be closed again after we left.  We lucked out and were dry most of the time.

The last night we were at Arches it was clear, except on the horizon, in just about every direction.  There was a large thunderstorm off to the northeast on the horizon (over Grand Junction, Colo.).  I spent most of the time viewing rather than imaging, as there was just so much that I wanted to see in a “real” dark sky.  Plus the clouds were starting to roll in after a few hours.

It just blew me away how dark it was and how much I could see! M27 was extremely bright in the scope! Eagle, Trifid, Lagoon, Omega Nebulas were all very easy to see! Even M97, the Owl Nebula, was not that difficult to see, and it was low to the horizon.

One object that I enjoyed viewing was NGC 7662, The Blue Snowball Nebula, a small planetary nebula not much bigger than Saturn. It kind of looks like very large hazy blueish star.

I did try some imaging but just didn’t have enough time before the clouds rolled in.  I managed to get M27 with about 15 minutes of total exposure.  I tried for the Eagle (M16) but the clouds were coming in and I knew that I could not get two hours like I would have needed.  I only managed about 20 minutes on M16 which was clearly not even close to being enough

Image Details:

    • 29 Light images
    • 30 sec each
    • ISO 1600
    • Canon 5D Mark II (un-modified)
    • Celestron EdgeHD 8 Inch
    • Shot at prime with Celestron T adapter
    • Processed with PixInsight and GIMP
    • 15 Darks
    • 10 Bias
    • No Flats
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