Unseen Dark Comets 'Could Pose Deadly Threat To Earth'

'Dark' comets happen when the water on their surface has evaporated,
causing them to reflect less light Photo: GETTY

From The Telegraph:

Unseen "dark" comets could pose a deadly threat to earth, astronomers have warned.

The comets, of which there could be thousands, are not currently monitored by observatories and space agencies.

Most comets and asteroids are monitored in case they start to travel towards earth.

But Bill Napier, from Cardiff University, said that many could be going by unnoticed.

"There is a case to be made that dark, dormant comets are a significant but largely unseen hazard," he said

Scientists estimate that there should be around 3,000 comets in the solar system, but only 25 have so far been identified.

"Dark" comets happen when the water on their surface has evaporated, causing them to reflect less light.

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