David Kirkpatrick

March 8, 2010

Things that make you go “oh, my”

Filed under: Science — Tags: , , , , , — David Kirkpatrick @ 2:54 pm

Via KurzweilAI.net — Oh my, indeed.

Dark, dangerous asteroids found lurking near Earth
New Scientist Space, Mar. 5, 2010

NASA‘s WISE mission has spotted 16 formerly hidden near-Earth objects with orbits close to Earth‘s.

WISE is expected to discover as many as 1000 near-Earth objects, but astronomers estimate that the number of unknown objects with masses great enough to cause ground damage in an impact runs into the tens of thousands.
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February 2, 2010

Head-on asteroid crash — cool space image

Filed under: Science — Tags: , , , , , — David Kirkpatrick @ 4:33 pm

This bit of interesting news is from this morning’s inbox. Very cool image

Suspected Asteroid Collision Leaves Trailing Debris

WASHINGTON, Feb. 2 /PRNewswire-USNewswire/ — NASA’s Hubble Space Telescope has observed a mysterious X-shaped debris pattern and trailing streamers of dust that suggest a head-on collision between two asteroids. Astronomers have long thought the asteroid belt is being ground down through collisions, but such a smashup has never been seen before.

(Logo:  http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO)

Asteroid collisions are energetic, with an average impact speed of more than 11,000 miles per hour, or five times faster than a rifle bullet. The comet-like object imaged by Hubble, called P/2010 A2, was first discovered by the Lincoln Near-Earth Asteroid Research, or LINEAR, program sky survey on Jan. 6. New Hubble images taken on Jan. 25 and 29 show a complex X-pattern of filamentary structures near the nucleus.

“This is quite different from the smooth dust envelopes of normal comets,” said principal investigator David Jewitt of the University of California at Los Angeles. “The filaments are made of dust and gravel, presumably recently thrown out of the nucleus. Some are swept back by radiation pressure from sunlight to create straight dust streaks. Embedded in the filaments are co-moving blobs of dust that likely originated from tiny unseen parent bodies.”

Hubble shows the main nucleus of P/2010 A2 lies outside its own halo of dust. This has never been seen before in a comet-like object. The nucleus is estimated to be 460 feet in diameter.

Normal comets fall into the inner regions of the solar system from icy reservoirs in the Kuiper belt and Oort cloud. As comets near the sun and warm up, ice near the surface vaporizes and ejects material from the solid comet nucleus via jets. But P/2010 A2 may have a different origin. It orbits in the warm, inner regions of the asteroid belt where its nearest neighbors are dry rocky bodies lacking volatile materials.

This leaves open the possibility that the complex debris tail is the result of an impact between two bodies, rather than ice simply melting from a parent body.

“If this interpretation is correct, two small and previously unknown asteroids recently collided, creating a shower of debris that is being swept back into a tail from the collision site by the pressure of sunlight,” Jewitt said.

The main nucleus of P/2010 A2 would be the surviving remnant of this so-called hypervelocity collision.

“The filamentary appearance of P/2010 A2 is different from anything seen in Hubble images of normal comets, consistent with the action of a different process,” Jewitt said. An impact origin also would be consistent with the absence of gas in spectra recorded using ground-based telescopes.

The asteroid belt contains abundant evidence of ancient collisions that have shattered precursor bodies into fragments. The orbit of P/2010 A2 is consistent with membership in the Flora asteroid family, produced by collisional shattering more than 100 million years ago. One fragment of that ancient smashup may have struck Earth 65 million years ago, triggering a mass extinction that wiped out the dinosaurs. But, until now, no such asteroid-asteroid collision has been caught “in the act.”

At the time of the Hubble observations, the object was approximately 180 million miles from the sun and 90 million miles from Earth. The Hubble images were recorded with the new Wide Field Camera 3 (WFC3), which is capable of detecting house-sized fragments at the distance of the asteroid belt.

For Hubble images and more information, visit:

http://www.nasa.gov/hubble

Photo:  http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO
AP Archive:  http://photoarchive.ap.org/
PRN Photo Desk photodesk@prnewswire.com
Source: NASA

Web Site:  http://www.nasa.gov/

And to save a trip to the Hubble site, here’s the image:

Hubble image of comet-like object P/2010 A2

Credit: NASA, ESA, and D. Jewitt (University of California, Los Angeles). Photo No. STScI-2010-07

October 7, 2009

Good news, everyone …

Filed under: Science — Tags: , , , , , — David Kirkpatrick @ 1:41 pm

… the Earth is much less likely to hit by an asteroid in 2036 than previously expected. (And, yes, the Futurama reference is intentional.)

The NASA release from today’s inbox:

NASA Refines Asteroid Apophis’ Path Toward Earth

PASADENA, Calif., Oct. 7 /PRNewswire-USNewswire/ — Using updated information, NASA scientists have recalculated the path of a large asteroid. The refined path indicates a significantly reduced likelihood of a hazardous encounter with Earth in 2036.

(Logo: http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO)

The Apophis asteroid is approximately the size of two-and-a-half football fields. The new data were documented by near-Earth object scientists Steve Chesley and Paul Chodas at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. They will present their updated findings at a meeting of the American Astronomical Society’s Division for Planetary Sciences in Puerto Rico on Oct. 8.

“Apophis has been one of those celestial bodies that has captured the public’s interest since it was discovered in 2004,” said Chesley. “Updated computational techniques and newly available data indicate the probability of an Earth encounter on April 13, 2036, for Apophis has dropped from one-in-45,000 to about four-in-a million.”

A majority of the data that enabled the updated orbit of Apophis came from observations Dave Tholen and collaborators at the University of Hawaii’s Institute for Astronomy in Manoa made. Tholen pored over hundreds of previously unreleased images of the night sky made with the University of Hawaii’s 88-inch telescope, located near the summit of Mauna Kea.

Tholen made improved measurements of the asteroid’s position in the images, enabling him to provide Chesley and Chodas with new data sets more precise than previous measures for Apophis. Measurements from the Steward Observatory’s 90-inch Bok telescope on Kitt Peak in Arizona and the Arecibo Observatory on the island of Puerto Rico also were used in Chesley’s calculations.

The information provided a more accurate glimpse of Apophis’ orbit well into the latter part of this century. Among the findings is another close encounter by the asteroid with Earth in 2068 with chance of impact currently at approximately three-in-a-million. As with earlier orbital estimates where Earth impacts in 2029 and 2036 could not initially be ruled out due to the need for additional data, it is expected that the 2068 encounter will diminish in probability as more information about Apophis is acquired.

Initially, Apophis was thought to have a 2.7 percent chance of impacting Earth in 2029. Additional observations of the asteriod ruled out any possibility of an impact in 2029. However, the asteroid is expected to make a record-setting — but harmless — close approach to Earth on Friday, April 13, 2029, when it comes no closer than 18,300 miles above Earth’s surface.

“The refined orbital determination further reinforces that Apophis is an asteroid we can look to as an opportunity for exciting science and not something that should be feared,” said Don Yeomans, manager of the Near-Earth Object Program Office at JPL. “The public can follow along as we continue to study Apophis and other near-Earth objects by visiting us on our AsteroidWatch Web site and by following us on the @AsteroidWatch Twitter feed.”

The science of predicting asteroid orbits is based on a physical model of the solar system which includes the gravitational influence of the sun, moon, other planets and the three largest asteroids.

NASA detects and tracks asteroids and comets passing close to Earth using both ground and space-based telescopes. The Near Earth-Object Observations Program, commonly called “Spaceguard,” discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet.

JPL manages the Near-Earth Object Program Office for NASA’s Science Mission Directorate in Washington. Cornell University operates the Arecibo Observatory under a cooperative agreement with the National Science Foundation in Arlington, Va.

For more information about asteroids and near-Earth objects, visit:

http://www.jpl.nasa.gov/asteroidwatch

For more information about NASA, visit:

http://www.nasa.gov/

Photo:  http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO
AP Archive:  http://photoarchive.ap.org/
PRN Photo Desk photodesk@prnewswire.com
Source: NASA

Web Site:  http://www.nasa.gov/

November 25, 2008

About that Canadian meteorite last week …

Filed under: Science — Tags: , , , , , — David Kirkpatrick @ 9:05 pm

… most likely ten tons!

The release:

Meteorite search update

10-ton rock responsible for fireball in Western Canada last week

Investigation of the fireball that lit up the skies of Alberta and Saskatchewan on November 20 has determined that an asteroid fragment weighing approximately 10 tonnes entered the Earth’s atmosphere over the prairie provinces last Thursday evening. And University of Calgary researcher Alan Hildebrand has outlined a region in western Saskatchewan where chunks of the desk-sized space rock are expected to be found.

The fireball first appeared approximately 80 kilometres above and just east of the border city of Lloydminster, Alberta/Saskatchewan, and traveled SSE towards the Battle River valley fragmenting spectacularly in a series of explosions. The fireball penetrated the atmosphere at a steep angle of approximately 60 degrees from the horizontal and lasted about five seconds from 17:26:40 to 17:26:45 MST with the largest explosion at 17:26:44. The fireball was recorded on all-sky and security cameras scattered across Saskatchewan and Alberta in addition to being witnessed by tens of thousands of people who saw it streak across the sky, saw its arc- welding blue flash, or heard the subsequent explosions.

“Firstly, we are enormously appreciative of all the people who have volunteered information about the fireball. The public response to this fireball has been the largest that we have ever had in Canada.” said Hildebrand, Canada Research Chair in Planetary Science and Coordinator of the Canadian Fireball Reporting Centre at the University of Calgary. Hildebrand said the fireball was like a billion-watt lightbulb shining in the sky, turning night into day with a bluish white light. It illuminated the ground for several hundred kilometers in all directions including as far south as Vauxhall, Alberta.

“Thanks to everyone’s help we are now beginning to delineate the trajectory of the fireball, so that its prefall orbit can be determined. We have also outlined an area where its meteorites may have fallen, although we will have more precise predictions to come,” Hildebrand added.

The asteroid fragment is now known to have weighed approximately 10 tonnes when it entered the Earth’s atmosphere from an energy estimate derived from infrasound records by Dr. Peter Brown, Canada Research Chair in Meteor Physics at the University of Western Ontario. Infrasound is very low frequency sound produced by explosions that can travel thousands of kilometers.

“At least half a dozen infrasound stations ranging from Greenland to Utah, including Canada’s Lac Du Bonnett, Manitoba and Elgin Field, Ontario stations, recorded energy from the fireball’s explosions. The indicated energy is approximately one third of a kiloton of TNT,” Brown said.

Dr. Brown also says that a fireball this size only occurs over Canada once every five years on average. About ten fireballs of this size occur somewhere over the Earth each year.

Dr. Hildebrand spent the weekend in the field interviewing witnesses and searching for security camera videos.

“We are now trying to get all the transient information about the fireball before it is lost. Many motels and gas stations only keep their security recordings for one week or less, so we urge everyone to check their systems to see if they recorded the fireball or the moving shadows that it cast,” Hildebrand said. “Three gas stations and motels in Lloydminster, Lashburn and Maidstone are known to have records, but dozens of other businesses in the area probably have the fireball or its shadows recorded.”

If fireball images are found, he suggests immediately saving a copy and contacting him. “With the security camera footage we can compute the fireball’s trajectory in the sky to calculate the prefall orbit. Meteorites have only ever been recovered from known orbits nine times previously and we want to make that ten. ”

Hildebrand estimates that hundreds of meteorites larger than 50 grams could have landed since the rock was large and its entry velocity was lower than average. The object’s speed is calculated to be only roughly 14 km/sec when it entered the atmosphere versus the average of around 20 km/sec.

“We are now starting to reasonably constrain where the meteorites will have fallen. Many witnesses reported seeing a cluster of red fragments continuing downwards in the sky after the fireball exploded. These represent the rocks slowing down that will eventually fall to the ground as meteorites,” Hildebrand said. “An outstanding thing about this fireball is that so many red fragments were seen and that they traveled so low to the ground before becoming invisible in the darkness.”

The projected area of fall lies within Saskatchewan’s Manitou Lake Rural Municipality north of Marsden and Neilburg, and just south of the Battle River in an area that is mostly cleared for cultivation.

“Several of the nearby eye witnesses describe sounds that could actually be from the meteorites falling through the sky, but we don’t know that for sure yet. The eye witness descriptions are remarkably consistent with each other as to the location,” Hildebrand said.

The remarkable consistency of the eyewitness accounts is probably partly explained by the dramatic dust clouds that marked the fireball’s path. These clouds remained in the sky without much distortion for several minutes. From the fireball’s characteristics Hildebrand thinks that it was a relatively strong rock and many rocks the size of a football or bigger are expected in addition to the more numerous small ones. Larger meteorites will have plunged into the ground if at all soft, making small pits with the meteorites at the bottom. Meteorites of common asteroids will have a dark gray or black coating covering their dimpled surface, be denser than the average rock, and will weakly attract a magnet, but other types of meteorites are possible.

The meteorites are expected to be scattered across a strewnfield approximately eight km long and three km wide with the larger stones to the southeast. Noting that they have a substantial commercial value, Hildebrand also advises that meteorites are the property of the landowner where they fall.

Hildebrand and Brown are both members of the Small Bodies Discipline Working Group that is funded by the Canadian Space Agency. Dr. Martin Beech at the University of Regina chairs this working group.

Hildebrand has returned to the field to continue gathering data. 

###

 

See Google Map of search area at: http://maps.google.ca/maps/ms?ie=UTF8&hl=en&msa=0&msid=101407268858136267770.00045c7664e5121a35b7f&ll=52.957946,-109.741573&spn=1.111851,2.570801&z=9

June 27, 2008

Nanowire circuits and tracking asteroids

From KurzweilAI.net, the House passed a bill to begin tracking potential Earth-strike asteroids, and a new low-cost, high-volume method of integrating nanowires onto silicon has been developed.

House passes bill mandating a plan for asteroid warning and deflection
KurzweilAI.net, June 27, 2008

In recently passed H.R.6063, The U.S. House of Representatives would direct the NASA Administrator to develop plans for a low-cost spacemission to rendezvous with the Apophis asteroid and attach a tracking device (subject to Senate approval).

The Apophis is expected to pass at a distance from Earth that is closer than geostationary satellites in 2029.

The bill would also require the Director of the White House’s Office of Science and TechnologyPolicy (OSTP) to develop a policy within two years for notifying Federal agencies and relevant emergency response institutions of an impending near-Earth objectthreat. And the OSTP would be required to recommend a Federal agency (or agencies) to be responsible for protecting the Nation from any near-Earth object anticipated to collide with Earth, and for implementing a deflection campaign.

 

Researchers develop new technique for fabricating nanowire circuits
Nanowerk News, June 26, 2008

Scientists at Harvard University and German universities of Jena, Gottingen, and Bremen have developed a reproducible, high-volume, low-cost fabrication methodfor integrating nanowire devices directly onto silicon.

The method incorporates spin-on glass technology, used in silicon integrated circuits manufacturing, and photolithography, transferring a circuit pattern onto a substrate with light. These devices can then function as light-emitting diodes, with the color of light determined by the type of semiconductor nanowire used.

Because nanowires can be made of materials commonly used in electronics and photonics, they hold great promise for integrating efficient light emitters, and could lead to the development of a completely new class of integrated circuits, such as large arrays of ultra-small nanoscale lasers that could be designed as high-density optical interconnects or used for on-chip chemical sensing.

 
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