The best comet
hunter in history recently spotted its 1,000th comet, accounting for
nearly half the comets ever discovered.
The Solar and Heliospheric Observatory (SOHO), which is run by NASA and
the European Space Agency, was designed to watch the Sun, but has since proved
to have excellent ability at spotting comets.
The images
SOHO took were posted to the internet and amateur sky-watchers had the
opportunity to find and report new comets. Amateurs were finding comets so
quickly that SOHO operators decided to make a contest of it, awarding a prize
to the person who discovered the 1,000th comet.
Italian high
school teacher Toni Scarmato got lucky on Aug. 5 and
spotted comets numbers 999 and 1,000 in the same SOHO image.
"I am very
happy for this special experience that is possible thanks to the SOHO satellite
and NASA-EVA collaboration," Scarmato said. "I want
to dedicate the SOHO 1000th comet to my wife Rosy and my son Kevin
to compensate for the time that I have taken from them to search for SOHO
comets."
For his
accomplishment, Scarmato will receive a SolarMax DVD, a SOHO T-shirt, solar viewing glasses, and
more.
A second SOHO
comet-spotting contest awarded prizes to Andrew Dolgopolov
of Ireland for the closest guess - within 22 minutes - of when the 1,000th
comet would be spotted.
The SOHO
spacecraft was engineered to watch solar
eruptions and the ensuing space weather that sometimes bombards Earth.
But early on
in the mission, armchair astronomers figured out they could become comet
discoverers using SOHO images posted to the Web. Because SOHO is trained on
the Sun, it only sees comets that whiz by the Sun, called Sun grazers.
Sun grazers
are often hard to spot because they are lost in the glare from the overwhelming
light produced by the Sun. But SOHO is equipped with a device that blocks light
from the Sun's main disk so detailed images can be made of the solar atmosphere
and surrounding space.
"Before
SOHO was launched, only 16 sun grazing comets had been discovered by space
observatories," said Chris St. Cyr, senior project scientist for NASA's
'Living With a Star' program at the agency's Goddard
Space Flight Center. "Based on that experience, who could have predicted
SOHO would discover more than 60 times that number, and in only nine
years."
Some 85
percent of all SOHO comets belong to the Kreutz
group, named because their orbits take them within 500,000 miles of the Sun's
visible surface. Some make a trip around the Sun and head back out to the far
reaches of the solar system on wildly elongated orbits. Others don't make it,
being gravitationally drawn right
into the star on close approach.
Other comets
discovered without SOHO, such as one named Kudo-Fujikawa,
have at times been watched in real
time by web surfers as they dramatically sliced across SOHO's
field of view. In 2003, a comet named NEAT, whose path in front of the SOHO
cameras was well predicted, was smacked by a
solar storm, the first such event ever recorded.
SOHO is a
joint effort between NASA and the European Space Agency. It has accounted for
about half of all comet discoveries, through history, in which orbits have been
calculated.
A timeline for
milestone comets spotted by SOHO (comet number and date spotted):
100: Feb. 4, 2000
200: Aug. 31, 2000
300: Mar. 25, 2001
400: Feb. 26, 2002
500: Aug. 14, 2002
600: Apr. 29, 2003
700: Dec. 2, 2003
800: June 11, 2004
900: Jan. 15, 2005
1000: Aug. 5, 2005
advertisement
