Sizzling Water | by Brian Koberlein



12 October 2014

A group of sunspots.
NASA Goddard House Flight Middle
A bunch of sunspots.

Yesterday I talked about how water can type on the Moon. It may appear a bit shocking that water exists on the Moon, nevertheless it doesn’t sound like a loopy concept. What does sound loopy is the concept there’s water on the Solar’s floor, and but we all know that there’s.

The floor of the Solar (particularly the photosphere) has a temperature of about 6000 Okay. It’s so scorching that hydrogen atoms are ionized, and molecules may be ripped aside. It’s fairly inhospitable for a molecule akin to water. Regardless of this, the potential for water is there. Oxygen is produced in stars via the CNO fusion cycle, and we now have noticed portions of oxygen within the Solar’s spectra. Hydrogen is essentially the most considerable component within the universe, and a lot of the Solar’s mass is hydrogen. All that’s wanted is a cool sufficient temperature for the hydrogen and oxygen to come back collectively to type water.

It seems there’s simply such a spot in sunspots. We usually consider sunspots as darkish areas on the Solar. They aren’t really darkish, however they’re cooler and dimmer than the remainder of the Solar, which is why they seem darkish in photo voltaic photographs. Inside a big sunspot, the temperature may be as cool as 3500 Okay, which is cool sufficient for water to type. Naturally it solely exists as water vapor, however there actually is water on the Solar’s floor.

The red line is the theoretical spectra for water at 3000K. The blue line is the observed curve in sunspots.
Polyansky, et al
The purple line is the theoretical spectra for water at 3000K. The blue line is the noticed curve in sunspots.

The presence of water on the Solar has lengthy been suspected, however proving it has been an actual problem. That’s as a result of water has a fancy spectra with tens of millions of absorption traces. These traces additionally range with temperature, making it much more difficult. Experimentally measuring the road spectra of water vapor at 3500 Okay isn’t possible, so it’s essential to calculate the anticipated spectra utilizing laptop simulations.

In 1997, a workforce did simply that. They had been capable of calculate greater than 6 million absorption traces for highly regarded water, after which in contrast the outcomes to noticed spectra deep inside sunspots. They discovered a transparent match, exhibiting that water does certainly type inside “cool” sunspots.

So sure, there actually is water on the Solar’s floor. It’s a reality value remembering should you ever wish to win a bar wager.

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