Russian Meteorite Impact: Meteor's Origin and Size Determined

A meteor that exploded over Russia earlier this month likely hit Earth after a long trip from beyond the orbit of Mars, scientists say.

Astronomers and the public were caught off guard by the Russian fireball, which damaged thousands of buildings and wounded more than 1,000 people when it detonated over the city of Chelyabinsk on Feb. 15.

But some YouTube-aided detective work suggests that the meteor's parent body belonged to the Apollo family of Earth-crossing asteroids, whose elliptical orbits take them farther than one Earth-sun distance (about 93 million miles, or 150 million kilometers) from our star at some point, researchers said.



Jorge Zuluaga and Ignacio Ferrin of the University of Antioquia in Medellin, Colombia, reached this conclusion after analysing several videos of the Russian meteor, especially one taken in Chelyabinsk's Revolutionary Square and another recorded in the nearby city of Korkino.

They also took into account the location of a hole in the ice of Lake Chebarkul, about 43 miles (70 km) from Chelyabinsk. Scientists think the hole was caused by a piece of the space rock that hit Earth on Feb. 15.

Using trigonometry, Zuluaga and Ferrin calculated basic elements of the fireball's path through Earth's atmosphere.

"According to our estimations, the Chelyabinski meteor started to brighten up when it was between 32 and 47 km up in the atmosphere," they write in their paper, which has been posted to the online astronomy preprint site ArXiv.org.

"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."

Ural Federal University scientist

The pair then entered these figures into a software program developed by the United States Naval Observatory called NOVAS (short for Naval Observatory Vector Astrometry), which calculated the likely orbit of the meteor's parent body.

Some other scientists agree that this orbit took the space rock relatively far from the sun at times — farther than Mars, in fact.

"It came from the asteroid belt, about 2.5 times farther from the sun than Earth," Bill Cooke, of NASA's Meteoroid Environment Office at the Marshall Space Flight Center in Huntsville, Ala., said in a statement. Cooke was not involved in Zuluaga and Ferrin's study.

Meanwhile, the size of the meteor's parent object has come into clearer focus, thanks to measurements made by a global network of infrasound sensors operated by the Comprehensive Test Ban Treaty Organization (CTBTO).

These sensors monitor extremely low-frequency sound waves, which are a common product of nuclear explosions.

As the Russian meteor burned through Earth's atmosphere, it generated the most powerful infrasound signal ever detected by the CTBTO network, researchers said, and this signal revealed a great deal about the asteroid's size, speed and explosive power.

"The asteroid was about 17 meters in diameter and weighed approximately 10,000 metric tons," Peter Brown, a physics professor at the University of Western Ontario in Canada, said in a statement.

"It struck Earth's atmosphere at 40,000 mph and broke apart about 12 to 15 miles above Earth's surface. The energy of the resulting explosion exceeded 470 kilotons of TNT."

That's 30 to 40 times more powerful than the atomic bomb the United States dropped on the Japanese city of Hiroshima during World War II.

The Russian fireball likely produced the most powerful such space rock blast since a 130-foot (40 m) object exploded over Siberia in 1908, flattening 825 square miles (2,137 square km) of forest.

Preliminary reports suggest that the Chelyabinsk fireball's parent asteroid was composed primarily of stone, with a smidge of iron thrown in.

"In other words, [it's] a typical asteroid from beyond the orbit of Mars," Cooke said. "There are millions more just like it."

The Russian meteor struck just hours before the 130-foot asteroid 2012 DA14 gave Earth a close shave, missing our planet by just 17,200 miles (27,000 km), but the two space rocks are unrelated, researchers say, making Feb. 15 a day of remarkable cosmic coincidences.

You can see the Arxiv paper on the Russian meteor here.

Scientists Discover Planet with Diamond Mantle - Twice The Size Of Our Sun

Scientists have announced the discovery of a planet made almost entirely of diamonds.

The planet, called 55 Cancri e, is located in a solar system inside the constellation of Cancer, reports NBC News.

It was discovered in 2004, and scientists have been working since then to determine its mass and radius, as well as study its host star’s composition.

The planet is called a “super-Earth,” and scientists believe that the rocky world is composed mostly of carbon (in the form of either graphite or diamond). It also includes iron, silicon carbide, and possibly silicates.

Scientists also believe, based on their research, that at least one-third of the planet’s mass is pure diamond. Lead researcher Nikku Madhusudhan of Yale University stated:

“This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth. The surface of this planet is likely covered in graphite and diamond rather than water and granite.”

While worlds like the “diamond planet” of 55 Cancri e have been theorized before, and at least one has been discovered before now, it is the first of its kind to be identified orbiting around a sun-like star.

Madhusudhan’s study on the planet was published in the journal Astrophysical Journal Letters.

Princeton University astronomer David Spergel stated that it is relatively easy to find out a star’s basic structure and history once its age and mass have been discovered. He added:

“Planets are much more complex. This ‘diamond-rich super-Earth’ is likely just one example of the rich sets of discoveries that await us as we begin to explore planets around nearby stars.”

ESA Astronaut ISS Image: Weightless!

Mass but no weight. Moving experiment hardware.

Credit: ESA/NASA

Astronomically Large Lenses Measure Age And Size Of Universe

When a large nearby object, such as a galaxy, blocks a distant object, such as another galaxy, the light can detour around the blockage. But instead of taking a single path, light can bend around the object in one of two, or four different routes, thus doubling or quadrupling the amount of information scientists receive.

As the brightness of the background galaxy nucleus fluctuates, physicists can measure the ebb and flow of light from the four distinct paths, such as in the B1608+656 system imaged above. (Image courtesy Sherry Suyu of the Argelander Institut fur Astronomie in Bonn, Germany.)


Using entire galaxies as lenses to look at other galaxies, researchers have a newly precise way to measure the size and age of the universe and how rapidly it is expanding, on a par with other techniques.

The measurement determines a value for the Hubble constant, which indicates the size of the universe, and confirms the age of the universe as 13.75 billion years old, within 170 million years. The results also confirm the strength of dark energy, responsible for accelerating the expansion of the universe.

These results, by researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at the US Department of Energy's SLAC National Accelerator Laboratory and Stanford University, the University of Bonn, and other institutions in the United States and Germany, will be published in The Astrophysical Journal in March.

The researchers used data collected by the NASA/ESA Hubble Space Telescope, and showed the improved precision they provide in combination with the Wilkinson Microwave Anisotropy Probe (WMAP).

The team used a technique called gravitational lensing to measure the distances light traveled from a bright, active galaxy to the earth along different paths. By understanding the time it took to travel along each path and the effective speeds involved, researchers could infer not just how far away the galaxy lies but also the overall scale of the universe and some details of its expansion.

Oftentimes it is difficult for scientists to distinguish between a very bright light far away and a dimmer source lying much closer. A gravitational lens circumvents this problem by providing multiple clues as to the distance light travels. That extra information allows them to determine the size of the universe, often expressed by astrophysicists in terms of a quantity called Hubble's constant.

"We've known for a long time that lensing is capable of making a physical measurement of Hubble's constant," KIPAC's Phil Marshall said. However, gravitational lensing had never before been used in such a precise way. This measurement provides an equally precise measurement of Hubble's constant as long-established tools such as observation of supernovae and the cosmic microwave background. "Gravitational lensing has come of age as a competitive tool in the astrophysicist's toolkit," Marshall said.