A University of Pittsburgh astronomer announced the discovery of one or more planets orbiting a star only 8 light-years from the Earth this week, the latest and closest discovery of extrasolar planets.
"The main point is that I see something going around the star," said George Gatewood, who presented his results at the American Astronomical Society meeting in Madison, Wisconsin.
The star in question is Lalande 21185, a small red star about 8 light-years from the Earth, and closer than all but a handful of known stars. Gatewood, using a 75-cm (30-inch) telescope at Pittsburgh's Allegheny Observatory, had been monitoring an unusual wobble in the motion of the star.
The complicated wobble suggests that more than one object is orbiting the star, but the data cannor resolve the number or sizes of them. The data also cannot determine whether the object is a planet or a more massive but more distant brown dwarf.
Gatewood has plans to continue his work using a larger telescope in hopes of being able to distinguish the number and masses of the objects orbiting the star.
Like a 98-pound weakling that turns into a Charles Atlas bodybuilder, the universe seems to be putting on weight, although cosmologists are concerned it's using the cosmic equivalent of junk food to bulk itself up.
"The universe has been putting on weight lately, and astronomers, like anxious parents, are pleased to see it filling out," the editors of Science magazine wrote in a recent issue.
For many years astronomers have known that only a small percent -- 1 to 10 percent -- of the mass needed to prevent the eventual collapse of the universe into a Big Crunch was visible. Now, thanks to observations from the Hubble Space Telescope and the Keck Observatory, that fraction is increasing.
Most of the gain has been the discovery of dim stars and other bodies in halos around galaxies like the Milky Way, objects known collectively as MACHOs. Observations suggest the amount of mass that could be held by MACHOs is still far short of the amount to prevent a Big Crunch.
Cosmologists who favor theories that provide for just enough mass in the universe to avoid a Big Crunch believe another source of dark matter exists in the universe to account for the missing mass.
Astronomers reported this week that the solar system is approaching a cloud of interstellar gas that will, over the next 50,000 years, alter the solar environment and shower Earth with more cosmic radiation.
The solar system is currently in an empty area of space between two spiral arms of the Milky Way galaxy, according to astrophysicist Priscilla Frisch of the University of Chicago. However, the motion of the solar system around the galactic center will soon bring us into a cloud up to a million times denser than the current cloud.
A denser interstellar environment would damp out the solar wind. As the solar wind carries harmful cosmic radiation away from the Earth, and decrease in the solar wind would expose the Earth to more radiation. In addition, the increased density of gas and dust from the cloud would absorb more solar radiation at visible wavelengths, dimming the sun as seen from Earth.
The cloud, about sixty light-years in diameter, is still more than four light-years from the Earth and moving at speeds far smaller than the speed of light, so there is no immediate effects expected on the Earth.
The research was presented at the meeting of the American Astronomical Society in Madison, Wisconsin.
[Last Section: Policy] [Next Section: CyberSpace]
[Table of Contents] [SpaceViews Forum]