An artist’s im­pres­sion of Plan­et GJ 367b.
Credit: SPP 1992 (Patricia Klein)

Do you know someone who listens to heavy metal music? Maybe you have friends who like to wear black clothing and bang their heads to loud tunes. Perhaps you have an uncle who’s into Ozzy Osbourne or Van Halen. You may know someone who’s pretty metal, but that person is probably an absolute creampuff compared with the heavy metal planet recently discovered by German scientists.

The planet, designated GJ367b, is an exoplanet, a planet orbiting a star beyond our solar system. It orbits a red dwarf star some 31 light-years from Earth in the southern constellation Vela, the Sails. One light-year is this distance light travels in one year, about 5.88 trillion miles (9.46 trillion kilometers).

At about 3/4 the size of Earth, GJ367b is the smallest exoplanet yet discovered. But, that does not mean that it is a lightweight. The exoplanet has a density of 8 grams per cubic centimeter, compared with about 5.5  grams per cubic centimeter for Earth. This extreme density suggests that GJ367b is the most metallic planet yet discovered. It probably consists mostly of an iron core, perhaps surrounded by a thin layer of rock.

The planet’s density is not its only extreme characteristic. The planet orbits extremely close to its parent star, whipping around the red dwarf every eight hours. If you lived on GJ367b, you might be able to celebrate your birthday about three times each Earth day. You probably wouldn’t like the weather, though. Daytime temperatures reach a sizzling 1500 °C (2700 °F). That’s almost hot enough to melt the planet’s metal. In fact, GJ367b may have an atmosphere composed of evaporated rock.

That scientists were able to learn so much about such a small planet shows just how far the hunt for exoplanets has advanced. Scientists discovered GJ367b using the Transiting Exoplanet Sky Survey (TESS) telescope, announcing the discovery in December. The TESS telescope identifies exoplanets by measuring changes in a star’s light as an orbiting planet transits (passes in front of) it. Scientists hope to learn even more about this heavy metal world with the launch of the James Webb Space Telescope.

April 18, 2012

The U. S. space shuttle Discovery made its final voyage on Tuesday, April 17, hitching a ride aboard a modified Boeing 747 jumbo jet. Discovery was flown from Kennedy Space Center in Florida to Dulles International Airport in Virginia. There, the shuttle is to become an exhibit at the Smithsonian National Air and Space Museum annex in Chantilly. Discovery replaced the shuttle prototype Enterprise, which will go on exhibit in New York City.

Columbia was the first space shuttle to be launched into space, in 1981. (Courtesy of NASA)

Discovery first flew into space in August 1984, on a mission to deploy three communications satellites. It was the third shuttle in the fleet, following Columbia and Challenger. Discovery carried the Hubble Space Telescope into space in 1990. After the explosions of Challenger in 1986 and Columbia in 2003, Discovery, along with the shuttles Atlantis and Endeavour, carried on the task of ferrying parts and crew members to build the International Space Station (ISS). Construction of the ISS began in 1998, and the shuttles completed the delivery of major station modules by 2011. Discovery flew 39 missions in all, more than any other shuttle. Since its first flight, Discovery has logged more than 148 million miles (238 million kilometers) and spent a cumulative 365 days in space.

The U.S. fleet of space shuttles was instrumental in building the ISS, a space station program in which 15 nations are involved.  (Courtesy of NASA)

President George W. Bush announced plans in 2004 to end the space shuttle program. By that time, engineers had become concerned about the safety of the aging vehicle–the first reusable spacecraft. The government determined that private contractors would take over the shuttle’s responsibilities at the ISS and that NASA would devote its resources to exploring space. The shuttle Endeavour was slated to be put on exhibit in Los Angeles, while Atlantis was to remain at the Kennedy Space Center. Nearly 2,000 people gathered to see Discovery’s final voyage and to mark the end of an amazing era of space exploration.

Additional World Book articles:

• Thirty Years of Discovery (a special report)
• Seeing the Universe in a Different Light (a special report)
• Space exploration 1981 (Back in Time article)
• Space exploration 1984 (Back in Time article)
• Space exploration 1986 (Back in Time article)
• Space exploration 1990 (Back in Time article)
• Space exploration 2000 (Back in Time article)
• Space exploration 2003 (Back in Time article)
• Space exploration 2011 (Back in Time article)

Jan. 9, 2012

The mystery of how a highly unusual material found in a rock from a Russian mountain could have been created naturally on Earth may have been answered: It didn’t. A new study by scientists from Princeton University suggests that the material, called a quasicrystal, came from outer space in a meteorite. Moreover, the meteorite may be older than Earth itself. The finding indicates that materials that could never form naturally on Earth can form in space–which has scientists wondering what other materials are out there.

In a crystal, atoms are arranged in an orderly manner, with a regularly repeating pattern. The atoms in a quasicrystal also have an orderly arrangement, but they do not have a regularly repeating pattern. Scientists once thought that quasicrystals were an impossibility. In fact, when Daniel Shechtman, an Israeli engineer, reported his discovery of quasicrystals in 1982, the scientific community dismissed his findings completely. (In 2011, Shechtman won the Nobel Prize in chemistry for his discovery.) Several years after his discovery, other scientists made more quasicrystals in various arrangements. Then in 2009, scientists reported finding a naturally occurring quasicrystal in a rock from Russia’s Koryak Mountains.

Now Princeton scientists have reported that the Koryak quasicrystal appears not to have formed naturally on Earth after all. The rock apparently is the remains of a meteorite that formed 4.5 billion years ago, even before Earth had taken shape in the early solar system. In the rock sample, the scientists found a tiny grain of a mineral called stishovite, which occurs only at the kind of high pressure achieved in meteorite impacts and collisions. The quasicrystal was encased in the stishovite.

Both quasicrystals and crystals, such as these salt crystals, contain atoms that are arranged in an orderly pattern. But the atoms in quasicrystals do not follow the kind of repeating pattern found in crystals. (c) Charles Falco, Science Source from Photo Researchers

Many quasicrystals have practical uses. Certain quasicrystals can be particularly strong and hard. They are mixed with such metals as aluminum and steel and other alloys (mixture of metals) to increase a metal’s strength and hardness. Quasicrystals may also exhibit nonstick abilities, such as those found in the nonstick coatings on cookware.

Additional World Book articles:

• Mineral
• Symmetry