Comet Returns After 37,000 Years

A recently-discovered comet makes its closest approach to the Sun. Moments later, it seems to be struck by a super-hot outburst of gas from the star.

This spectacular image was spotted on Tuesday by a spacecraft, the Solar and Heliospheric Observatory (Soho).

The joint European Space Agency/Nasa satellite is designed to give warnings of stormy space weather that might affect the Earth.

Soho has photographed hundreds of comets around the Sun but this one, known as Neat, has only just been seen.

It has been hovering in the evening sky for the past few weeks but is hardly visible without a telescope.

The comet is putting on a spectacular show Calculations show it has passed through the inner Solar System once before but this was 37, 000 years ago.

The comet is unusual in that it is very large and very bright. In fact it is the brightest comet ever observed by one of Soho's instruments.

Scientists are studying its interaction with the solar wind - the hot, charged particles flowing from the Sun.

OK- I thought you were implying that the oceans were formed as a result of planetary interaction with comet's tails.

As for the origin of plantary oceans, you may be interested to know that recent research has pushed back the existence of oceans on the primeaval Earth by nearly a billion years. They were present virtually from the beginning.

http://www.freerepublic.com/focus/news/839466/posts

This is important support for the cold Earth theories and for the important work on planetary formation by Thomas Gold.

Actually, I was suggesting that water can be delivered to planets as they pass through the tails of comets.

Your first thought upon reading this may be "Get this guy some tinfoil", but it is not difficult to do the calculations.

First of all, it is FAR more likely for a planet to pass through a comet's tail, than it is for a direct collision between a comet and a planet. This is because the tails are so much larger than the comet nuclei.

If you agree with this reasoning, then the remaining question is: How much water could be delivered by passage through a comet's tail? I did some research (delaying my response to your post), and found enough information to perform a "back of the envelope" type of calculation.

To make the calculations we need to know:

How much water sublimates from a comet when it is in the inner solar system?
How fast is the solar wind?

I found that Comet Hale-Bopp produced about 4000 tonnes of water vapor per second, and the solar wind ranges from ~0 to ~700 km/sec.

Using this information, and a simple conical model of the comet tail, one can calculate the water vapor density in the tail at any distance from the nucleus. (The density is VERY low in all cases)

The clincher is that planets sweep through enormous volumes of space as they orbit the Sun. (Earth sweeps through about 3.8 billion cubic km of space every second)

According to my calculations using a mean solar wind velocity of 300 km/sec and conical tail 30 degrees wide, a Hale-Bopp sized comet could deliver about 50 Tonnes/sec. from a distance of 20 million km (inside earth's orbit). For comparison purposes, the Amazon river delivers ~280,000 Tonnes/sec to the Atlantic ocean, so this water delivered from space would probably go unnoticed except by astronomers.

Not much, but over the life of the solar system, it adds up.

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