Freitag, 13. Juni 2014 - 07:16

Astronomie - Asteroid 2014 KH39 zog nur 1,1 LD von der Erde entfernt am 3. Juni vorbei und der nächste ist schon im Anmarsch mit HQ124 - Update

2,06.2014

Near Earth asteroid 2014 KH39, discovered on May 24, 2014, is the faint ‘star’ in the crosshairs in this photo made on May 31. The telescope tracked the asteroid, so the stars are trailed. A satellite trail is visible too. Credit: Gianluca Masi

Got any plans Tuesday? Good. Keep them but know this. That day around 3 p.m. CDT (20:00 UT) asteroid 2014 KH39 will silently zip by Earth at a distance of just 272,460 miles (438,480 km) or 1.14 LDs (lunar distance). Close as flybys go but not quite a record breaker. The hefty space rock will buzz across the constellation Cepheus at nearly 25,000 mph (11 km/sec) near the Little Dipper at the time.

Observers in central Europe and Africa will have dark skies for the event, however at magnitude +17 the asteroid will be too faint to spot in amateur telescopes. No worries. The Virtual Telescope Project, run by astrophysicist Gianluca Masi, will be up and running with real-time images and live commentary during the flyby. The webcast begins at 2:45 p.m. CDT June 3.

2014 KH39 was discovered on May 24 by the automated Mt. Lemmon Sky Survey. Further observations by the survey and additional telescopes like Pan-STARRS 1 in Hawaii nailed down its orbit as an Earth-approacher with an approximate size of 72 feet (22 meters). That’s a tad larger than the 65-foot Chelyabinsk asteroid that exploded into thousands of small stony meteorites over Russia in Feb. 2013.

Diagram showing the orbit of 2014 KH39. Yellow shows the portion of its orbit above the plane of Earth’s orbit (grey disk); blue is below the plane. When farthest, the asteroid travels beyond Mars into the asteroid belt. It passes closest to Earth around 3 p.m. CDT June 3. Credit: IAU Minor Planet Center

Since this asteroid will safely miss Earth we have nothing to fear from the flyby. I only report it here to point out how common near-Earth asteroids are and how remarkable it is that we can spot them at all. While we’re a long ways from finding and tracking all potentially hazardous asteroids, dedicated sky surveys turn up dozens of close-approaches every year. On the heels of 2014 KH39, the Earth-approaching asteroid 2014 HQ124 will pass 3.3 LDs away 5 days later on June 8. With a diameter estimated at more than 2,100 feet (650-m) it’s expected to become as bright as magnitude +13.7. Southern hemisphere observers might track it with 8-inch and larger telescopes as its speeds across Horologium and Eridanus the morning before closest approach.

The chart shows the cumulative known total of near-Earth asteroids (NEAs) vs. time. The blue area shows all NEAs while the red shows those roughly 1 km and larger. Thanks to many ground-based surveys underway as well as space probes like the Wide-field Infrared Survey Explorer (WISE), discovery totals have ramped up in recent years. There are probably millions of NEOs smaller than 140 meters waiting to be discovered. Credit: NASA

Perusing the current list of upcoming asteroid approaches, these two will be our closest visitors at least through early August. Near-Earth objects (NEOs) are comets and asteroids whose original orbits have been re-worked by the gravity of the planets – primarily Jupiter – into new orbits that allow them to approach relatively close to Earth. The ones we’re most concerned about are a subset called Potentially Hazardous Asteroids or PHAs, defined as objects that approach within 4.65 million miles (7.48 million km) of Earth and span 500 feet (150-m) across or larger. The key word here is ‘potential’. PHAs won’t necessarily hit the Earth – they only have the potential to do so over the vastness of time. On the bright side, PHAs make excellent targets for sampling missions.

As of May 30, 2014, 11,107 near-Earth objects have been discovered with 860 having a diameter of 1 km or larger. 1,481 of them have been further classified as potentially hazardous. NASA’s Near-Earth Object Program estimates that over 90% of NEOs larger than 1 km (the most potentially lethal to the planet) have been discovered and they’re now working to find 90% of those larger than 459 feet (140 meters) across. Little by little we’re getting to better know the neighborhood.

The probability that either 2014 KH39 and 2014 HQ124 will hit Earth on this round is zero. Nor do we know of any asteroid in the near future on a collision course with the planet. Enjoy the day.

Quelle: UT

Update: 6.06.2014

Riesenasteroid beinahe übersehen: „The Beast“ nähert sich der Erde

Zehnmal so groß wie der Tscheljabinsk-Meteorit: Der Asteroid HQ124 „The Beast“ rast am Sonntag an der Erde vorbei. Für unseren Planeten besteht keine Gefahr. Dennoch schlagen Experten Alarm, weil der Riesenasteroid erst im letzten Moment entdeckt worden ist.

HQ124 fliegt am 8. Juni in rund einer Million Kilometer Entfernung an die Erde vorbei. Das entspricht etwa der dreifachen Entfernung von der Erde zum Mond. Mit einem Durchmesser von 325 Metern ist der Himmelskörper mindestens zehnmal so groß und schwer wie der 12-Tonnen-Meteorit, der im Februar 2013 über der russischen Ural-Stadt Tscheljabinsk explodiert war und schwere Schäden verursacht hatte. Experten verweisen darauf, dass ein derart großes kosmisches Geschoss erst am 23. April entdeckt worden sei. Es wäre also möglich, dass ein anderer Asteroid, der unseren Planeten zerstören kann, zu spät entdeckt wird.

„Was besonders beunruhigend ist, dass ein derart großer steinerner beziehungsweise metallener Körper, der so nahe an der Erde vorbei fliegt, so kurz vor seiner größten Annäherung entdeckt wurde“, sagte Astronom Bob Berman vom australischen Astronomieprojekt Slooh. „HQ124 ist 10- bis 20mach größer als der Asteroid, der im vergangenen Jahr in Tscheljabinsk tausend Menschen verletzt hat“, sagte Bergman nach Angaben von Space.com.

Am 15. Februar 2013 war ein Meteorit im russischen Gebiet Tscheljabnisk eingeschlagen. Durch seine Druckwelle gingen Fensterscheiben in mehr als 7000 Gebäuden zu Bruch. Über 1600 Menschen zogen sich Verletzungen zu.

Quelle: RIANOVOSTI

Update: 7.06.2014

Big 'Beast' Asteroid Flies by Earth Sunday: What Would Happen if It Hit Us?

The near-Earth asteroid 2014 HQ124 is seen via telescope from Australia in this June 5, 2014 photo captured by the online Slooh community observatory. The asteroid will fly by Earth, outside the orbit of the moon, on June 8.

Humanity should be thankful "The Beast" doesn't have Earth in its crosshairs.

This Sunday (June 8), the near-Earth asteroid 2014 HQ124 — which some observers have nicknamed "The Beast" — will give the planet a relatively close shave, coming within 777,000 miles (1.25 million kilometers) at its closest approach, or about 3.25 times the distance from Earth to the moon.

There is no chance of an impact on this pass, researchers stress. But at 1,100 feet (335 meters) wide, 2014 HQ124 could do some serious damage if it slammed into us.

"This one would definitely be catastrophic if it hit the Earth," asteroid impact expert Mark Boslough, of Sandia National Laboratories in New Mexico, said Thursday (June 5) during a webcast produced by the online Slooh community observatory that previewed 2014 HQ124's upcoming flyby.

"If it hit a city, it would definitely wipe out an entire metropolitan area," Boslough added.

The orbit of near-Earth asteroid 2014 HQ124, first discovered on April 23, 2014, is shown in this NASA graphic. The asteroid will fly by Earth Sunday, June 8, at a safe distance of three times the Earth-moon distance.

"If it hit a city, it would definitely wipe out an entire metropolitan area," Boslough added.

Asteroid 2014 HQ124 is currently traveling about 31,000 mph (50,000 km/h) relative to Earth, Boslough said. But if the asteroid were on a collision course, our planet's gravity would boost its speed up to about 40,000 mph (64,000 km/h) at the time of impact.

If 2014 HQ124 is one solid piece of rock — its composition isn't known for certain — the strike would unleash an explosion with a yield of about 2,000 megatons, Boslough added. For comparison, the atomic bomb the United States dropped on the Japanese city of Hiroshima during World War II packed about 15 kilotons. (One megaton is equivalent to 1,000 kilotons.)

"You'd end up with a crater about 3 miles across," Boslough added. "An event like that would break windows over 100 kilometers away."

Asteroid 2014 HQ124 was discovered on April 23, just six weeks ago — not nearly enough time to deflect the asteroid if it were on a collision course with Earth. But that doesn't mean the asteroid would kill millions of people if it struck New York City or Tokyo.

"Once it's within radar distance, the precision is remarkably good on its position and speed," Boslough said. "So the folks at JPL [NASA's Jet Propulsion Laboratory] would be able to predict its impact point to within the nearest kilometer and its time to within the nearest second."

There would thus probably be plenty of time to organize an effective evacuation campaign if 2014 HQ124 were headed straight for us. But that isn't always always the case, as some (smaller) space rocks slam into the planet without ever being detected.

In February 2013, for example, a 65-foot-wide (20 m) asteroid detonated without warning in the sky above the Russian city of Chelyabinsk, shattering thousands of windows and injuring more than 1,200 people. And there are many more objects out there like the Chelyabinsk asteroid — small space rocks cruising unnamed through the dark depths of space.

Scientists estimates that they've found about 95 percent of the potential "civilization-enders" out there — mountain-size asteroids at least 0.6 miles (1 km) across. But there are probably more than 1 million near-Earth asteroids at least 100 feet (30 m) wide, and less than 1 percent of them have been discovered.

Quelle: SN

Update: 13.06.2014

'Beast' Asteroid Looks Like a Beauty in Radar Images

Before it flew past Earth, the asteroid 2014 HQ124 was nicknamed "the Beast" — but now that astronomers have captured pictures of it using a couple of the world's biggest radio dishes, they have a different name for it.

"These radar observations show that the asteroid is a beauty, not a beast," Alessondra Springmann, a data analyst at the Arecibo Observatory, said Thursday in a news release.

The radar images, acquired using Arecibo's 1,000-foot-wide (305-meter-wide) dish in Puerto Rico and the 230-foot (70-meter) Goldstone DSS-14 antenna in California, show that 2014 HQ124 looks something like a bowling pin. This pin is at least 1,200 feet (370 meters) wide and spins on its axis every 20 hours or so.

Arecibo and Goldstone are able to see the detail in radar reflections where most ground-based telescopes would see only a point of light. Recently installed equipment in Puerto Rico made it possible to combine Goldstone's superior 3.75-meter image resolution with Arecibo's greater sensitivity.

Mike Nolan, a staff scientist at the Arecibo Observatory, said that double-team capability makes it possible to characterize the structure of asteroid far more precisely. That level of detail will affect how asteroid-watchers deal with the perils and prospects to come.

"Say you wanted to send a mission to push on an asteroid," Nolan told NBC News. "It would help a lot to know if it was a pile of gravel or solid rock. And if you're going to mine an asteroid, you'd want to know if you should bring a shovel or some dynamite."

It's a bit too early to say exactly what kind of animal the Beast is. But Lance Benner, a scientist at NASA's Jet Propulsion Laboratory who led the radar observations at Goldstone, suggested in a news release that 2014 HQ124 may have been formed from two smaller asteroids that came together as a "contact binary."

The asteroid was discovered on April 23, and was judged big enough to destroy entire cities if it were to hit Earth in the wrong place. That's what led to the "Beast" nickname. Fortunately, the Beast flew past us on Sunday at a completely safe distance of 776,000 miles (1.25 million) kilometers, or slightly more than three times the distance between Earth and the moon.

The radar views were acquired shortly after the closest approach, while 2014 HQ124 was zooming away at a distance of 864,000 to 902,000 miles (1.39 million to 1.45 million kilometers).

Update for 1:50 p.m. ET June 12: I've added in some comments from Nolan, and also had a chance to ask Springmann what she thought the Beast looked like. "I have a little toy penguin on my desk," she said, and the radar images remind her of that penguin — right down to a radar shadow that looks like the bird's beak.

Quelle: NBC

Frams: NASA-Video

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