Comet Tempel 1 has smashed into the Deep Impact probe, producing a blast of light that prompted the mission control room at NASA鈥檚 Jet Propulsion Laboratory in California, US, to erupt into cheers and applause.
快猫短视频s and engineers jumped in the air, pumped their fists and hugged one another. Not only had their mission to deliberately collide with a comet for the first time succeeded perfectly, but the prospect of a damp squib 鈥� with the impactor passing right through a diffuse, rubbly comet 鈥� had fizzled away.
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鈥淕eez, and we thought it was going to be subtle,鈥� exulted JPL scientist Don Yeomans, one of the Deep Impact science team. 鈥淭hat was considerably brighter, and had considerably more material coming out, than I had expected,鈥� he said.
鈥淲e are just ecstatic,鈥� said JPL director Charles Elachi of the success of the $330 million mission. 鈥淚t was worth every penny we spent on it.鈥�
The aim of the cosmic collision was to punch a hole in the comet鈥檚 crusty surface to release material from below, revealing details about the interior of comets. These bodies of ice and dust a few kilometres across are believed to contain primordial material, preserved since the formation of the solar system in the deep-freeze of space.
Huge plume
One reason for the spectacular burst could be that puncturing the comet鈥檚 crust released subsurface pressure, allowing a much bigger plume of ejecta to spurt out, Yeomans said.
However, it will take detailed analysis to confirm exactly what happened 83 million miles from Earth. 鈥淗ow a washing-machine sized impactor could produce such a large disturbance is going to take some explanation,鈥� Yeomans said.
Even before the impact itself, the twin spacecraft 鈥� the impactor itself, and the flyby craft which moved aside to observe it 鈥� were both returning images far more detailed than any previous images of a comet鈥檚 nucleus. At about 28 centimetres, the maximum image resolution is almost 100 times better than the previous best comet images, taken in 2004 by the Stardust mission.
The pictures show numerous perfectly circular features, which could either be impact craters or sinkholes. They also display long linear features and a varied topography of rough areas and one smooth region 鈥� 鈥渆verything a geologist would love鈥�, Yeomans said.
Unidentified spectra
Dozens of observatories on Earth, as well as four in orbit, were also watching the comet at the time of impact, during which the comet brightened to six times its pre-impact level.
One was the Hubble Space Telescope, which took three images, presented an animation . It shows the inner cloud of dust and gas surrounding the comet鈥檚 nucleus increasing by 200 kilometres (about 120 miles) in size.
It will take days to collect and analyse all the measurements, says Deep Impact principal investigator Michael A鈥橦earn. But it is already clear that there are some unidentified spectral features in the light reflected from the ejected material, meaning the mission鈥檚 goal of learning new things about the internal composition of the comet will clearly be fulfilled.
And the amazing images returned by the probe immediately after the impact represent just 10% of the total taken, A鈥橦earn added: 鈥淭here are many more spectacular images.鈥�
Sandblasting fear
The Deep Impact team were not only delighted by the success of the impact, but also by the survival of the flyby spacecraft after it was spattered by debris from the comet鈥檚 tail, or coma.
鈥淚t is completely intact,鈥� says Keyur Patel, the Deep Impact deputy project manager. And pictures returned since show that the craft鈥檚 optics survived as well, escaping a feared sandblasting of its lenses.
But there is one possible downside to the spectacular plume produced by the impact, Yeomans told 快猫短视频. The fan of dust was so large, bright and long lasting that it may have blocked the flyby craft鈥檚 attempts to take pictures of the resulting crater.
The craft only had a 13-minute window to take such pictures. 鈥淭he dust we kicked up made things a little more difficult 鈥� it鈥檚 fairly opaque,鈥� he says.
Project scientists were so unsure of the impact鈥檚 effects that they had a betting pool as to how large the crater would be 鈥� one of the most important indicators of the structure of the comet nucleus.
You can view a movie of Deep Impact鈥檚 approach to comet Tempel 1 between 1 May and 2 July, two days before the impact. It is made up of images from the spacecraft鈥檚 medium-resolution camera and shows three flare-ups of gas and dust.
NASA has produced a series of videos showing:
聲 The flash when the comet ran over the probe, .
聲 The flash, .
聲 The , right up to seconds before impact.
