NASA Spots Record Breaking Huge Comet

Nasa has spotted a record-breakingly large comet headed nearer to Earth.

Its icy nucleus is bigger than any ever seen – measuring around 80 miles across, and 50 times bigger than the heart of most known comets.

It is also thought to have a mass of about 500 trillion tons – a hundred thousand times more massive than the typical comet found closer to the Sun The comet will not get closer than a billion miles from the Sun – further away even than the planet Saturn – and that will not happen until 2031.

The object has been known about since November 2010, at which point it was 3 billion miles from the Sun or the distance to Neptune. Since then, researchers have been looking to understand more about it, using telescopes both in space and on Earth.

As part of that research, scientists used Nasa’s Hubble Space Telescope to estimate the size of the comet, and revealed its huge size.

Researchers had thought that the comet must be at least reasonably large, given how active it is even at such a long distance from the Sun. But the new data came from five photos taken earlier this year by Hubble.

However, measuring the size is not as simple as taking those images. Scientists must distinguish the solid nucleus at the middle from the large dusty coma that wraps around it, and it is too far away for the images to be clear enough to tell the difference.

Instead, scientists looked at the bright dot of light that marked the nucleus at the heart of the comet. They then made a computer model of the coma that would surround it and adjusted it in line with the images.