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BBC News Online: Sci/Tech

Thursday, 17 February, 2000, 18:13 GMT

Shooting star observed from space

The satellite captured this image while looking down on the Earth

By BBC News Online science editor Dr David Whitehouse

Scientists from the United States' Naval Research Laboratory (NRL) have obtained the first ever image of a shooting star taken from space in the ultraviolet (UV) part of the spectrum.

Shooting stars or meteors are caused by tiny specks of cosmic debris burning up in the Earth's atmosphere.

The scientists say it is a valuable observation because it can help to reveal interesting details about the meteor's composition.

This is important because scientists believe that only certain types of meteors survive entry into the Earth's atmosphere. So observing these space rocks burn-up may allow researchers to better understand the different types of meteors.

The NRL team obtained the ultraviolet image using the Global Imaging Monitor of the Ionosphere (GIMI) instrument on board the US Department of Defense's Advanced Research and Global Observation Satellite (Argos).

The image was taken on 18 November, 1999, during the maximum of the annual Leonid meteor shower. At the time, the satellite was 833-km high and about 20-degrees south of the equator, over the South Pacific Ocean.

High altitude

Dr George Carruthers, GIMI principal scientist, says: "To our knowledge, this is the first observation of a meteor entry to the atmosphere in the far-UV spectral range. Such an entry cannot be observed from Earth's surface or from aircraft because of UV absorption by the lower atmosphere.

"This first observation from space of a meteor's UV light adds another dimension to the handful of previous space observations of meteors," adds Dr Noah Brosch of the Department of Astronomy and Astrophysics at Tel Aviv University in Israel.

"Once we have an opportunity to analyse our data and examine other images for events of this type," says Carruthers, "we may establish the feasibility of using far-UV spectroscopic instruments to more accurately measure the compositions of incoming meteoroids."

Scientists estimate that in order to be observable, the meteor had to have been at an altitude well above 100 kilometres.

Related to this story:
Leonid strikes the Moon (23 Nov 99 | Sci/Tech)
How to catch the Leonids (17 Nov 99 | Sci/Tech)
Voyage through a comet's trail (17 Nov 99 | Sci/Tech)

Internet Links: Naval Research Laboratory Meteors
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