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m1schuld
2008-Jan-31, 02:54 PM
I was reading about the new features found on Mercury, and I began to wonder:

I know that the side of Mercury facing the Sun is very hot and alternatively the side facing away is quite cool. What if I were able to travel to a point the same distance from the Sun as Mercury and measure the temperature of the "space" there. How close does one have to get to the Sun before the "space" around the sun is hot? Is their a gradual increase in temperature as one comes closer to the sun in empty space?

Neverfly
2008-Jan-31, 03:03 PM
I was reading about the new features found on Mercury, and I began to wonder:

I know that the side of Mercury facing the Sun is very hot and alternatively the side facing away is quite cool. What if I were able to travel to a point the same distance from the Sun as Mercury and measure the temperature of the "space" there. How close does one have to get to the Sun before the "space" around the sun is hot? Is their a gradual increase in temperature as one comes closer to the sun in empty space?

The thermometer will get hot while it's in the sunlight.
Heat can pass through space, but is not necessarily heating space.

So if you keep the sun from shining on the thermometer in the same place but then sheild it from the heat radiating from the sun- the temperature shown will drop.

Ross PK81
2008-Jan-31, 03:13 PM
I can't really see how empty space can be heated, but if the sun is shining on you then you'll feel the tempreture, since you yourself aren't empty space.

m1schuld
2008-Jan-31, 03:17 PM
So then I wonder if there is a particular location/distance where a comfortable temperature (for humans) exists -- say 68 degrees. How close to the sun would on have to be to maintain that temperature. Would their be any use for this temperate region?

Neverfly
2008-Jan-31, 03:20 PM
So then I wonder if there is a particular location/distance where a comfortable temperature (for humans) exists -- say 68 degrees. How close to the sun would on have to be to maintain that temperature. Would their be any use for this temperate region?

You mean how far from the sun in space in direct sunlight? Remember that only the front half of the object will be heated.

fotobits
2008-Jan-31, 03:21 PM
There is no such temperate region in space. Our planet has a relatively stable temperature because of our atmosphere. Space, being empty, cannot store heat like our atmosphere does. Consider the Moon. If you stand on the sunlit side you will feel heat from the Sun. If you stand on the dark side you will freeze.

Neverfly
2008-Jan-31, 03:25 PM
There is no such temperate region in space. Our planet has a relatively stable temperature because of our atmosphere. Space, being empty, cannot store heat like our atmosphere does. Consider the Moon. If you stand on the sunlit side you will feel heat from the Sun. If you stand on the dark side you will freeze.

The further from the sun you go, however, the less of the radiated energy you are receiving.

fotobits
2008-Jan-31, 03:26 PM
True Neverfly. My example was an oversimplification.

m1schuld
2008-Jan-31, 03:36 PM
Thanks for clearing this up for me!

aurora
2008-Jan-31, 05:25 PM
Thanks for clearing this up for me!

You also might be interested in the concept of a habitable zone (http://en.wikipedia.org/wiki/Habitable_zone)

Argos
2008-Jan-31, 06:07 PM
You might like to take a look at 'Black body (http://en.wikipedia.org/wiki/Black_body). Scroll down to Temperature relation between a planet and its star.

neilzero
2008-Feb-01, 11:03 PM
You have likely noticed that many thermometers read ten to twenty degrees higher in sunlight than in the shade. With very high vacuum such as near Mercury the difference is sometimes very large. There are many ways to measure temperature and the results very widely.
If we measure one million degrees k a thousand kilometers above the photosphere of our Sun, we may wonder how it can be 6500 degrees k inside the photosphere, when the heat source is at the Sun's core? The answer is something like there is almost no matter where the temperature is a million degrees.
The solar wind is blowing outward at about 500 kilometers per second could be considered a very high temperature? Neil

alainprice
2008-Feb-01, 11:31 PM
I don't feel like you're getting a full answer. If we consider 'space' to include the particles expected at that distance, then the corona and solar wind need to be added to this equation. I agree with Neil's answer the most.

I don't now know how far it extends, but is is very hot and there isn't much matter to it. Even at the distance of mercury, the light itself is going to be the main heating element.

mugaliens
2008-Feb-03, 07:27 PM
I was reading about the new features found on Mercury, and I began to wonder:

I know that the side of Mercury facing the Sun is very hot and alternatively the side facing away is quite cool. What if I were able to travel to a point the same distance from the Sun as Mercury and measure the temperature of the "space" there. How close does one have to get to the Sun before the "space" around the sun is hot? Is their a gradual increase in temperature as one comes closer to the sun in empty space?

You're mixing apples and oranges. There's conductive temp and radiated temp. One can be among 2,000 deg C, but if the density is low enough, nearly all heat is radiated away, and one feels very cold. Similarly, the radiated temp can be quite low, but under 14.7 psi if the air is 2,000 deg, the object coming into contact with the air will likely burn to a crisp.

In empty space, radiated temp is by far the major player. A simply aluminized mylar mirror between the spacecraft and the sun would cause the spacecraft to cool to near absolute zero temps, even at Mercury's orbit.

kleindoofy
2008-Feb-04, 03:12 AM
Maybe I can rephrase the original question as I would understand it:

Working on the - perhaps erroneous - assumption that the density of atomic matter in space is higher at Mercury's distance from the Sun than it is at 1AU, and again assuming that the strength of radiation emitted by Sun and of the solar wind is higher in that region than in ours, one would expect the energetic state of the individual atom in space at Mercury's distance from the Sun to be higher than here, which in turn could be understood as 'the heat of space,' making space 'hotter' near Mercury than near Earth.

I've always understood that the 'temperature' of dust clouds in space is measured this way, i.e. the energetic state of the atoms in the cloud.

The density of atomic matter in space is of course very minute, but matter is matter, regardless of how thinned out it is.

Is this just the overly-simplified layman's understanding of the situation, or am I correct?