Feb. 13, 2015

It is time to begin trying to contact aliens, according to a group of scientists from the SETI Institute in California. The term SETI refers to the Search for Extraterrestrial Intelligence—that is, intelligent life beyond Earth. SETI scientists recommended that Earth begin sending signals to planets outside our solar system to alert any intelligent civilizations to our presence. They made the recommendation this week at a meeting of the American Association for the Advancement of Science (AAAS) in San Jose, California.

The proposal, however, worries many scientists. Some are unsure what the message from Earth should be. Others argue that humans should avoid alerting aliens to our presence for fear of attracting visitors or even an alien invasion. This latter group includes the British theoretical physicist Stephen Hawking. “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans,” Hawking worries. But many scientists think the chances of attracting unwanted attention with such signals are remote.

For decades, the SETI Institute has used large radio telescopes and smaller optical (visible light) telescopes to search the sky for signals transmitted by extraterrestrial technology. However, SETI has yet to detect any evidence of alien civilizations. SETI researchers are now proposing that instead of just listening, we should start broadcasting our own signals toward exoplanets (planets outside our solar system). In recent years, scientists have discovered many such planets, including some in the so-called “habitable zone” of a nearby star. In this zone, temperatures allow for the existence of liquid water, which many scientists think is essential for life.

Other World Book articles:

• Allen Telescope Array

February 27, 2013

The name “Vulcan” was a surprise co-winner in the “Pluto Rocks” online contest in which the public was asked to help choose names for two moons recently discovered orbiting Pluto. “Vulcan,” which was not on the original ballot, was a write-in candidate suggested by actor William Shatner, who starred in the “Star Trek” science-fiction television and film series. “Vulcan” collected 174,062 of the 450,324 votes cast. “Cerberus,” the name of the three-headed dog that guarded the entrance to the underworld in Greek and Roman mythology, came in second, with nearly 100,000 votes. The contest was organized by astronomers with the SETI Institute, who found the moons in 2011 and 2012 using the Hubble Space Telescope. SETI is a research organization that searches for life in the universe beyond Earth.

Canadian-born actor William Shatner gained fame as Captain James T. Kirk, commander of the starship U.S.S. Enterprise in the television science-fiction series "Star Trek" (1966-1969). (© Paramount/The Kobal Collection)

The ballot for the “Pluto Rocks” contest originally included 12 names from Greek and Roman mythology associated with the underworld, also known as Hades. Pluto was the god of the dead in Roman mythology. He was almost identical to Hades, the Greek god of the dead. The SETI scientists agreed to add “Vulcan” to the ballot after Shatner promoted the name on Twitter. In Roman mythology, Vulcan was the god of fire, metalworking, and skilled craftwork in general. Although he did not dwell in Hades, he was a nephew of Pluto and was believed to have his blacksmith’s forge beneath Mount Etna in Sicily. Coincidentally, Vulcan was the name of the fictional home planet of Spock, the half-human first officer to Shatner’s Captain James T. Kirk.

Leonard Nimoy played the alien Mr. Spock in the "Star Trek" science-fiction television series and motion pictures. (NBC-TV/The Kobal Collection)

The SETI astronomers will now recommend the winning names to the International Astronomical Union (IAU), which determines the names of celestial bodies. The IAU, which is not required to accept the winning names, was expected to announce the new moons’ official names sometime this spring.

Additional World Book articles:

• New Horizons
• Space exploration
• Exploring the Suburban Solar System (a special report)
• Astronomy 1930 (Back in Time article)
• Astronomy 1978 (Back in Time article)
• Astronomy 2006 (Back in Time article)
• Space exploration 2006 (Back in Time article)

February 13, 2013

Astronomers with the SETI Institute, a research organization that searches for life in the universe beyond Earth, are giving the public a chance to help pick the names for the two newest moons discovered in orbit around Pluto. Now known as P4 and P5, the moons were found by astronomers at the institute in 2011 and 2012, respectively, using the Hubble Space Telescope (HST).

The ballot for the “Pluto Rocks” project includes 12 names from Greek and Roman mythology associated with the land of the dead, also known as Hades. Pluto was the god of the dead in Roman mythology. He was almost identical to Hades, the Greek god of the dead. The candidate names for the new moons include Cerberus, the three-headed dog that guarded the entrance to the underworld;  Hercules, who descended into Hades to capture Cerberus and bring him back to the upper world; Persephone, a goddess who was kidnapped by Pluto (Hades); and Styx, the gloomy river in the underworld. Pluto’s other three moons are Charon, named for the ragged old boatman who ferried the shades (spirits) of the dead across the Styx or other rivers of the underworld; Hydra, a many-headed serpent that had its den at the entrance to Hades; and Nix, the goddess of the night.

Hades, the Greek god of the underworld--with Cerberus--was known as Pluto in Roman mythology. (World Book illustration by Pat and Robin Dewitt)

The ballot can be found on the Internet at http://plutorocks.seti.org. Voting ends at noon Eastern Standard Time on February 25, 2013. After the voting, the astronomers will pick two names to submit to the International Astronomical Union (IAU), which determines the names of celestial bodies. The IAU was expected to announce the new moons’ official names sometime this spring.

Pluto was discovered by Clyde W. Tombaugh in 1930, based on predictions by astronomer Percival Lowell in 1905. The name for Tombaugh’s planet was suggested by Venetia Phair, an 11-year-old British girl, to her grandfather, a librarian, who passed on the suggestion to an astronomer friend. The friend cabled the name to the Lowell Observatory in Flagstaff, Arizona, where Tombaugh worked. Long considered the ninth planet in the solar system, Pluto was “demoted” from planet to a new category of space object called dwarf planet after astronomers in the 1990′s found many objects similar to Pluto in the outer reaches of the solar system, in an area called the Kuiper belt.

Additional World Book articles:

• New Horizons
• Space exploration
• Exploring the Suburban Solar System (a special report)
• Astronomy 1930 (Back in Time article)
• Astronomy 1978 (Back in Time article)
• Astronomy 2006 (Back in Time article)
• Space exploration 2006 (Back in Time article)

July 12, 2012

Astronomers using the Hubble Space Telescope (HST) have discovered another moon orbiting Pluto, announces NASA. The new satellite is the fifth found circling the small body, which for decades was widely considered the ninth planet in the solar system. Pluto was “demoted” from planet to a new category of space object called “dwarf planet” after astronomers in the 1990′s found many objects similar to Pluto in the outer reaches of the solar system, in an area called the Kuiper Belt. Pluto was discovered by Clyde W. Tombaugh in 1930, based on predictions by astronomer Percival Lowell in 1905. Pluto is 1,460 miles (2,350 kilometers) in diameter.

Pluto is so far from Earth and is so small that even powerful telescopes reveal little detail of its surface. The Hubble Space Telescope gathered the light for the pictures of Pluto shown here. (NASA)

Astronomers with the SETI Institute, a research organization that searches for life in the universe beyond Earth, discovered the new moon and gave it the temporary name P5. The astronomers are using the HST to study Pluto in preparation for a fly-by of the dwarf planet by the New Horizons space probe in July 2015. New Horizons was launched in 2006 to explore Pluto, its largest moon Charon, and other objects in the Kuiper Belt.

According to the researchers, P5 is a tiny, irregularly shaped body that measures from 6 to 15 miles (10 to 25 kilometers) across. The astronomers were unable to get a closer measurement because Pluto and its moons are about 2.8 billion miles (4.7 billion kilometers) away from Earth. Pluto’s moon Charon, which is about 750 miles (1,207 kilometers) in diameter, was discovered in 1978. Hydra and Nix, each up to 100 miles (160 kilometers) in diameter, were found in 2005. Pluto’s fourth moon, P4, discovered in 2011, is about 8 to 21 miles (13 to 34 kilometers) in diameter.

The scientists were a bit disconcerted by the discovery of an unknown moon as New Horizons is nearing Pluto. “All of this stuff poses a navigation hazard for New Horizons,” according to Ray Villard, news director of the Space Telescope Science Institute. However, tiny P5 has also produced a sense of wonder at the complexity of ex-planet Pluto’s system of satellites.

Additional World Book articles:

• Space exploration
• Exploring the Suburban Solar System (a special report)
• Astronomy 1930 (Back in Time article)
• Astronomy 1978 (Back in Time article)
• Astronomy 2006 (Back in Time article)
• Space exploration 2006 (Back in Time article)

Dec. 14, 2011

The Kepler space telescope has found the first confirmed Earth-like planet orbiting in the “habitable zone” of a distant star. The planet, named Kepler 22b, is about 2 ½ times as large as Earth. The habitable zone, also called the Goldilocks zone, is the region around a star that scientists believe is neither too hot nor too cold to support life as we know it. In this zone, the temperature is cool enough to let liquid water form and warm enough to prevent water from freezing. Earth orbits in the habitable zone of the solar system. Kepler’s sole mission, since the spacecraft’s launch in 2009, has been to spot planets circling distant stars.

Since the first extrasolar planet was discovered in the mid-1990′s, scientists have uncovered thousands of planets orbiting stars other than the sun. Because larger objects are easier to spot, most of the planets discovered so far are giants, many times larger than Jupiter, the largest planet in the solar system. Scientists have no way of knowing at this point if Kepler 22b has life. They think it is more likely that the planet is rocky, like Earth, rather than gaseous, like Neptune. It could even be an ocean world. They have calculated that if the planet has an atmosphere, the temperature there could be a pleasant 72 °F (22 °C).

The discovery comes just as the Allen Telescope Array (ATA) operated by the SETI Institute is back in operation. The 42 telescopes in the ATA, which were shut down early in 2011 because of budgetary problems, scan the sky for radio signals that could be signals from extraterrestrial beings. Over the next two years, SETI plans to focus the ATA at the top 1,000 habitable planets found by Kepler.

Additional World Book articles:

• COROT
• Kepler, Johannes
• Planet (Planets in other solar systems)

The United States government has no knowledge that extraterrestrial life exists or that beings from other planets have made contact with humans, according to a formal statement issued by the White House Office of Science and Technology Policy. In the statement, space policy expert Phil Larson declared, “The U.S. government has no evidence that any life exists outside our planet, or that an extraterrestrial presence has contacted or engaged any member of the human race. In addition, there is no credible information to suggest that any evidence is being hidden from the public’s eye.”

Some people believe UFO's are spaceships from other planets. However, investigators discover ordinary explanations for most UFO sightings. © Popperfoto/Alamy Images

The announcement was made in response to two online petitions addressed to “We The People,” a government website that promises to address issues raised by any petition with at least 5,000 signers. The petitions asked the administration of President Barack Obama for any government knowledge of contact with extraterrestrials (ET’s). One of the petitions insisted that, “The people have a right to know. The people can handle the truth.” Many people throughout the world believe that some unidentified flying objects (UFO’s) are spacecraft from other planets. Some people have even reported being abducted by aliens.

Larson acknowledged that the U.S. government has engaged in several projects to search for extraterrestrial life. In 2009, NASA launched Kepler, a space-based telescope designed to search for Earth-sized planets orbiting sun-like stars.  The SETI Institute in California also scans the universe for signs of intelligent life. In November, NASA planned to launch a new Mars rover named Curiosity. It is designed to search for evidence that Mars has had elements that could support microbial life. In 1952, the U.S. Air Force established Project Blue Book, a program to investigate about 12,000 UFO reports to determine whether UFO’s were a potential threat to national security. The project was cancelled in 1969, after scientists at the University of Colorado advised the Air Force that further study was not likely to produce useful information concerning a security threat.

Additional World Book articles:

• Area 51
• Roswell