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Asteroid Crashes And Raindrop Splashes Look Almost Alike


It’s hard to study what an asteroid impact does real-time as you’d need to be looking at the right spot at the right time. So simulations are often the way to go. Here’s a fun idea captured on video — throwing drops of water on to granular particles, similar to what you would find on a beach. The results, the researchers say, look surprisingly similar to “crater morphology”.
A quick caution — the similarity isn’t completely perfect. Raindrops are much smaller, and hit the ground at quite a lower speed than you would see an asteroid slam into Earth’s surface. But as the authors explain in a recent abstract, there is enough for them to do high-speed photography and make extrapolations…
…Read more at www.universetoday.com

The orbit of asteroid 1998 QE2. Image credit: NASA/JPL-Caltech

The orbit of asteroid 1998 QE2

Asteroid 1998 QE2 to Sail Past Earth Nine Times Larger Than Cruise Ship

The orbit of asteroid 1998 QE2. Image credit: NASA/JPL-Caltech

The orbit of asteroid 1998 QE2. Image credit: NASA/JPL-Caltech

On May 31, 2013, asteroid 1998 QE2 will sail serenely past Earth, getting no closer than about 3.6 million miles (5.8 million kilometers), or about 15 times the distance between Earth and the moon. And while QE2 is not of much interest to those astronomers and scientists on the lookout for hazardous asteroids, it is of interest to those who dabble in radar astronomy and have a 230-foot (70-meter) — or larger — radar telescope at their disposal.

“Asteroid 1998 QE2 will be an outstanding radar imaging target at Goldstone and Arecibo and we expect to obtain a series of high-resolution images that could reveal a wealth of surface features,” said radar astronomer Lance Benner, the principal investigator for the Goldstone radar observations from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Whenever an asteroid approaches this closely, it provides an important scientific opportunity to study it in detail to understand its size, shape, rotation, surface features, and what they can tell us about its origin. We will also use new radar measurements of the asteroid’s distance and velocity to improve our calculation of its orbit and compute its motion farther into the future than we could otherwise.”

The closest approach of the asteroid occurs on May 31 at 1:59 p.m. Pacific (4:59 p.m. Eastern / 20:59 UTC). This is the closest approach the asteroid will make to Earth for at least the next two centuries. Asteroid 1998 QE2 was discovered on Aug. 19, 1998, by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid Research (LINEAR) program near Socorro, New Mexico.

The asteroid, which is believed to be about 1.7 miles (2.7 kilometers) or nine Queen Elizabeth 2 ship-lengths in size, is not named after that 12-decked, transatlantic-crossing flagship for the Cunard Line. Instead, the name is assigned by the NASA-supported Minor Planet Center in Cambridge, Mass., which gives each newly discovered asteroid a provisional designation starting with the year of first detection, along with an alphanumeric code indicating the half-month it was discovered, and the sequence within that half-month.

Radar images from the Goldstone antenna could resolve features on the asteroid as small as 12 feet (3.75 meters) across, even from 4 million miles away.

“It is tremendously exciting to see detailed images of this asteroid for the first time,” said Benner. “With radar we can transform an object from a point of light into a small world with its own unique set of characteristics. In a real sense, radar imaging of near-Earth asteroids is a fundamental form of exploring a whole class of solar system objects.”

Asteroids, which are always exposed to the sun, can be shaped like almost anything under it. Those previously imaged by radar and spacecraft have looked like dog bones, bowling pins, spheroids, diamonds, muffins, and potatoes. To find out what 1998 QE2 looks like, stay tuned. Between May 30 and June 9, radar astronomers using NASA’s 230-foot-wide (70 meter) Deep Space Network antenna at Goldstone, Calif., and the Arecibo Observatory in Puerto Rico, are planning an extensive campaign of observations. The two telescopes have complementary imaging capabilities that will enable astronomers to learn as much as possible about the asteroid during its brief visit near Earth.

NASA places a high priority on tracking asteroids and protecting our home planet from them. In fact, the U.S. has the most robust and productive survey and detection program for discovering near-Earth objects. To date, U.S. assets have discovered over 98 percent of the known NEOs.

In 2012, the NEO budget was increased from $6 million to $20 million. Literally dozens of people are involved with some aspect of near-Earth object (NEO) research across NASA and its centers. Moreover, there are many more people involved in researching and understanding the nature of asteroids and comets, including those that come close to the Earth, plus those who are trying to find and track them in the first place.

In addition to the resources NASA puts into understanding asteroids, it also partners with other U.S. government agencies, university-based astronomers, and space science institutes across the country that are working to track and better understand these objects, often with grants, interagency transfers and other contracts from NASA.

NASA’s Near-Earth Object Program at NASA Headquarters, Washington, manages and funds the search, study, and monitoring of asteroids and comets whose orbits periodically bring them close to Earth. JPL manages the Near-Earth Object Program Office for NASA’s Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.

In 2016, NASA will launch a robotic probe to one of the most potentially hazardous of the known NEOs. The OSIRIS-REx mission to asteroid (101955) Bennu will be a pathfinder for future spacecraft designed to perform reconnaissance on any newly-discovered threatening objects. Aside from monitoring potential threats, the study of asteroids and comets enables a valuable opportunity to learn more about the origins of our solar system, the source of water on Earth, and even the origin of organic molecules that lead to the development of life.

NASA recently announced developing a first-ever mission to identify, capture and relocate an asteroid for human exploration. Using game-changing technologies advanced by the Administration, this mission would mark an unprecedented technological achievement that raises the bar of what humans can do in space. Capturing and redirecting an asteroid will integrate the best of NASA’s science, technology and human exploration capabilities and draw on the innovation of America’s brightest scientists and engineers.
Read more at http://www.jpl.nasa.gov/news/news.php?release=2013-163

A meteor seen flying over Russia on Feb. 15 at 3:20: 26 UTC impacted Chelyabinsk.

Russia Meteor Not Linked to Asteroid Flyby

A meteor seen flying over Russia on Feb. 15 at 3:20: 26 UTC impacted Chelyabinsk.

A meteor seen flying over Russia on Feb. 15 at 3:20: 26 UTC impacted Chelyabinsk.

New information provided by a worldwide network of sensors has allowed scientists to refine their estimates for the size of the object that entered that atmosphere and disintegrated in the skies over Chelyabinsk, Russia, at 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15).

The estimated size of the object, prior to entering Earth’s atmosphere, has been revised upward from 49 feet (15 meters) to 55 feet (17 meters), and its estimated mass has increased from 7,000 to 10,000 tons. Also, the estimate for energy released during the event has increased by 30 kilotons to nearly 500 kilotons of energy released. These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world – the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk. The infrasound data indicates that the event, from atmospheric entry to the meteor’s airborne disintegration took 32.5 seconds. The calculations using the infrasound data were performed by Peter Brown at the University of Western Ontario, Canada.

“We would expect an event of this magnitude to occur once every 100 years on average,” said Paul Chodas of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. “When you have a fireball of this size we would expect a large number of meteorites to reach the surface and in this case there were probably some large ones.”

The trajectory of the Russia meteor was significantly different than the trajectory of the asteroid 2012 DA14, which hours later made its flyby of Earth, making it a completely unrelated object. The Russia meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia….
Read more: www.nasa.gov

A VPython visualization of the asteroid’s orbital element  vectors and its orbit around the Sun. Angular momentum vector is in blue,  longitude of ascending node is in red, and eccentricity (pointing to  perihelion) is in orange. Asteroid is in brown. Earth’s (almost) circular  orbit (blue) in the plane of the ecliptic (green) is shown for scale of  distances (which are to scale). Sizes (i.e. radii) of Earth, Sun, and asteroid  are not to scale

The Orbit of Asteroid 1994 PC1

Simulation of the asteroid in a realistic Solar System to show gravitational perturbations. Sizes of Sun and planets are not to scale. Distances, inclination angles, and shapes of orbits are to scale.

Sophia Jane Balkoski, Laksh Bhasin, Milly KeQi Wang

A VPython visualization of the asteroid’s orbital element vectors and its orbit around the Sun. Angular momentum vector is in blue, longitude of ascending node is in red, and eccentricity (pointing to perihelion) is in orange. Asteroid is in brown. Earth’s (almost) circular orbit (blue) in the plane of the ecliptic (green) is shown for scale of distances (which are to scale). Sizes (i.e. radii) of Earth, Sun, and asteroid are not to scale

Near-Earth Asteroids can be hazardous to the Earth, due to their orbital characteristics and proximity to inner Solar System planets. Using three sets of CCD images collected in June and July 2011, the orbital elements of asteroid 1994 PC1 were determined at solar opposition. The body’s specific right ascension and declination were calculated through least squares plate reduction (taking parallax into account) and compared to those of the Jet Propulsion Laboratory. These data were then used to find 1994 PC1’s orbital elements, as well as any statistical uncertainty……
Read more: http://arxiv.org/pdf

NASA Dawn Spacecraft Returns Close-Up Image of Asteroid Vesta

NASA's Dawn spacecraft obtained this image with its framing camera on July 17, 2011. It was taken from a distance of about 15,000 kilometers away from the protoplanet Vesta. Each pixel in the image corresponds to roughly 1.4 kilometers

NASA’s Dawn spacecraft has returned the first close-up image after beginning its orbit around the giant asteroid Vesta. On Friday, July 15, Dawn became the first probe to enter orbit around an object in the main asteroid belt between Mars and Jupiter.

The image taken for navigation purposes shows Vesta in greater detail than ever before. When Vesta captured Dawn into its orbit, there were approximately 9,900 miles (16,000 kilometers) between the spacecraft and asteroid. Engineers estimate the orbit capture took place at 10 p.m. PDT Friday, July 15 (1 a.m. EDT Saturday, July 16).

Vesta is 330 miles (530 kilometers) in diameter and the second most massive object in the asteroid belt. Ground- and space-based telescopes have obtained images of Vesta for about two centuries, but they have not been able to see much detail on its surface. “We are beginning the study of arguably the oldest extant primordial surface in the solar system,” said Dawn principal investigator Christopher Russell from the University of California, Los Angeles. “This region of space has been ignored for far too long. So far, the images received to date reveal a complex surface that seems to have preserved some of the earliest events in Vesta’s history, as well as logging the onslaught that Vesta has suffered in the intervening eons.”

Vesta is thought to be the source of a large number of meteorites that fall to Earth. Vesta and its new NASA neighbor, Dawn, are currently approximately 117 million miles (188 million kilometers) away from Earth. The Dawn team will begin gathering science data in August. Observations will provide unprecedented data to help scientists understand the earliest chapter of our solar system. The data also will help pave the way for future human space missions.

After traveling nearly four years and 1.7 billion miles (2.8 billion kilometers), Dawn also accomplished the largest propulsive acceleration of any spacecraft, with a change in velocity of more than 4.2 miles per second (6.7 kilometers per second), due to its ion engines. The engines expel ions to create thrust and provide higher spacecraft speeds than any other technology currently available. “Dawn slipped gently into orbit with the same grace it has displayed during its years of ion thrusting through interplanetary space,” said Marc Rayman, Dawn chief engineer and mission manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “It is fantastically exciting that we will begin providing humankind its first detailed views of one of the last unexplored worlds in the inner solar system.”

Although orbit capture is complete, the approach phase will continue for about three weeks. During approach, the Dawn team will continue a search for possible moons around the asteroid; obtain more images for navigation; observe Vesta’s physical properties; and obtain calibration data.

In addition, navigators will measure the strength of Vesta’s gravitational tug on the spacecraft to compute the asteroid’s mass with much greater accuracy than has been previously available. That will allow them to refine the time of orbit insertion.

Dawn will spend one year orbiting Vesta, then travel to a second destination, the dwarf planet Ceres, arriving in February 2015. The mission to Vesta and Ceres is managed by JPL for the agency’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Ala.

UCLA is responsible for Dawn mission science. Orbital Sciences Corp. of Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are part of the mission’s team.

 

This composite image shows the comparative sizes of nine asteroids. Up until now, Lutetia, with a diameter of 81 miles (130 kilometers), was the largest asteroid visited by a spacecraft, which occurred during a flyby

http://www.nasa.gov/mission_pages/dawn/news/dawn20110718.html