[an error occurred while processing this directive]
BBC News
watch One-Minute World News
Last Updated: Wednesday, 6 July, 2005, 15:45 GMT 16:45 UK
Comet's huge plume hides crater
Comet Tempel 1 takes a battering
The plume of material was bigger and brighter than expected
Nasa's Deep Impact spacecraft may have missed its chance to see the crater made in Comet Tempel 1 because of the large plume of material kicked out.

Seeing the crater was a key objective of the mission - scientists hoped the impact depression would tell them more about the structure of the comet.

But the team can use indirect methods to estimate the crater's dimensions.

A 370kg "impactor" released into Tempel 1's path by the flyby spacecraft crashed into the comet on Monday.

"They can calculate the volume of material thrown out and that gives them a basic idea of the crater volume," Dr Paul Roche, director of the UK-run Faulkes Telescope in Hawaii, told the BBC News website.

The explosive moment of impact on Comet Tempel 1

Using a best estimate of the hardness of Tempel 1's surface, scientists can calculate a rough depth and radius for the crater.

But, said Dr Roche, "it's not as nice as seeing and measuring the crater itself".

Comet evolution

The US space agency (Nasa) might yet be able to resolve part of the crater using image processing software, he added.

Scientists had planned to study the depression to determine the strength and structure of material on the comet's surface and immediately below.

Comet Tempel 1, Faulkes Telescope
The Faulkes Telescope North took pictures before and after collision
The type of crater formed could have helped determine whether Tempel 1 was composed of relatively porous, pristine material or stronger, processed material. This would give clues to how comets formed and evolved.

Regardless, the mission will give scientists heaps of data to trawl through. And the plume itself will provide valuable information on the composition of the cometary material.

Dr Roche's team at the Faulkes Telescope has been tracking the intensity of the comet before and since Monday's impact.

"There is still material gushing out of the crater right now; Tempel 1 is still brighter than it was before impact. If the hole is deep enough, material could keep flooding out for weeks or months," he said.

"We saw a brightening and fading within the course of an hour-and-a-half to two hours."

School children from Hawaii, Iceland and the UK have been involved in processing the images.

See the first pictures of the impact

Comet crash clues for Europe
04 Jul 05 |  Science/Nature
Nasa probe strikes Comet Tempel 1
04 Jul 05 |  Science/Nature
Q&A: Deep Impact comet mission
04 Jul 05 |  Science/Nature
Animated Guide: Deep Impact
28 Jun 05 |  Science/Nature
Chase is on for comet spacecraft
28 Apr 05 |  Science/Nature
Comet mission's images are blurry
29 Mar 05 |  Science/Nature
Comet mission set for 2005 launch
15 Dec 04 |  Science/Nature
Nasa to crash probe into comet
27 May 01 |  Science/Nature

The BBC is not responsible for the content of external internet sites


News Front Page | Africa | Americas | Asia-Pacific | Europe | Middle East | South Asia
UK | Business | Entertainment | Science/Nature | Technology | Health
Have Your Say | In Pictures | Week at a Glance | Country Profiles | In Depth | Programmes
Americas Africa Europe Middle East South Asia Asia Pacific