February 2006 night sky

Be a considerate neighbor: Shield all your outside lights downward (or turn them off completely) and enjoy the beautiful, starry night sky.

—CHARLIE CHRISTMANN

CELESTIAL NEMESIS
Richard A. Muller, a physicist at the University of California at Berkeley, believes that there is an object orbiting the Sun that not only will cause, but already has caused mass extinctions on Earth many times. He calls this object Nemesis, the Death Star.

His idea is that our Sun has a companion star responsible for recurring episodes of wholesale death and destruction here on Earth. It's a theory that has many detractors. And it's a theory that has been beaten down and left for dead in the minds of most scientists. Yet it is a theory that just won't die. Nemesis is cautiously supported by a handful of scientists. Muller meanwhile acknowledges the possibility that the whole idea could turn out to be wrong, but he is nonetheless confident that Nemesis will be found within ten years.

Nemesis, named for the Greek Goddess of retribution, offers an explanation for the seemingly periodic mass extinctions that have occurred throughout the history of the Earth. The fossil record shows that mass extinctions have occurred on average every twenty-six to thirty-four million years.

The solar system has a cloud of debris called the Oort Cloud that orbits far from the sun. Its inner edge starts about ten thousand times farther from the Sun than the Earth's orbit. Its outer edge is 1.5 light-years away from the Sun. As Nemesis orbits, its elliptical orbit would bring it near or into the outer fringes of the Oort Cloud. The gravitational field of Nemesis would cause some comets to stray from their normally stable orbit and head toward the inner solar system. Some of these comets would hit the Earth, causing varying levels of global extinction. The comet showers would last anywhere from a hundred thousand years to two million years, with approximately ten impacts occurring about fifty thousand years apart. Fortunately, we have a few million years to go before the next cycle begins.

It is thought that Nemesis is probably a red-dwarf star with a magnitude between seven and twelve. Its size is believed to be a third of the Sun's and 1/1000 as bright. Some think that Nemesis is right under our noses. We may even be able to see it with a pair of binoculars. Even though all red-dwarf stars in our vicinity have been catalogued, the reason Nemesis has not been discovered is that only a few of the distances have been accurately measured, making it difficult for scientists to pinpoint which star could be Nemesis.

The ultimate evidence to support the Nemesis Theory would of course be the actual discovery of the Nemesis star. Until then, Earth faces other, more immediate threats.

Over the last few years, astronomers have been searching the sky for killer asteroids. To date 761 have been found to be crossing close enough to Earth's orbit to be of note. Many new asteroids in this category are discovered each year. In fact, four new potentially dangerous asteroids have been discovered since the first of the year. Though a few have passed inside the orbit of the Moon over the years, none are known to be on a collision course.

Planetary scientists have developed the Torino impact-hazard scale to rate the risk that an asteroid and comet might collide with the Earth. Similar to the Richter scale used for earthquakes, the Torino scale assigns values to celestial objects moving near Earth. The scale runs from zero to ten. An object with a value of zero or one will have virtually no chance of causing damage on Earth; a ten means a certain global catastrophe.

One asteroid, Apophis (2004 MN4), caused alarm in December 2004 because initial observations indicated a relatively large probability that it would strike the Earth in 2029. Though the asteroid will come very close to Earth in 2029, observations collected in the months of December 2004 and January 2005 by professional and amateur astronomers provided enough information to show that there will be no impact. A future impact on April 13, 2036, is still possible, keeping the asteroid at level one on the Torino scale, with an estimated impact probability of one in 6,250.

THE PLANETS AND THE MOON
• Mercury is rising just after the Sun this month, and will be impossible to see.
• Venus has become a morning star. Look for it rising in the east at 5:00 a.m. early in the month to 4:15 a.m. late in the month.
• Mars will be high in the sky at sunset and set around 1:30 am. Look for the Moon and Mars pairing on February 5.
• Jupiter rises in the east at 1:00 a.m. early in the month, 11:30 p.m. at the end of month. The Moon joins Jupiter on February 20.
• Saturn will be up in the east at sunset, reaching culmination about 11:00 p.m. On February 10, look for the Moon to cozy up to one side of Saturn. On February 11, the Moon will be nestled on the other side of the planet.
• The Moon is full on February 13 and new on February 28. February is the Full Snow Moon (if only we had some snow).

New astronomy society for the West Side

—RIO GRANDE ASTRONOMICAL SOCIETY
The Rio Grande Astronomical Society has just been formed to provide education and services to those interested in astronomy and amateur astronomy throughout the West Side. The organization was originally the Corrales Astronomy Club but is expanding to support existing and future members from the Montaño Bridge to Bernalillo and the Indian Pueblos north all the way to Jemez.

According to RGAS president Ed Isenberg, “Although we’ve only been operating since late summer, we’ve already grown to almost one hundred members, over half of whom are from outside Corrales. Clearly there was an unmet need for a West Side organization and we decided to fill it.”

The original organization has already held many meetings and observing sessions, plus several educational programs for schools and scouting groups. On Saturday, January 28, it will hold its first dark-sky observing session roughly forty-five minutes away from Rio Rancho.

Now RGAS hopes to dramatically expand its programs in Rio Rancho, northwest Albuquerque, and other areas. “We’ve even had requests from Jemez Pueblo to do programs for their new high school,” said Isenberg. “We hope this will become the first in many astronomy programs aimed at the Indian community.

RGAS has big plans for new services in the coming years, said Isenberg. “By incorporating as a nonprofit, we hope to attract grants that will eventually allow us to construct and operate a top-quality telescope observatory in a dark-sky area near Rio Rancho accessible to both adults and K-12 students throughout the West Side.

The new organization is run by an eight-person board of directors who have so much confidence in the opportunities RGAS will provide the West Side that they’ve dug into their own pockets to fund the Incorporation and the IRS application for nonprofit status, both now underway.

For more information, visit the Rio Grande Astronomical Society Web site, www.rgas.org, or call Isenberg, at 922-1072.