Dumb question about science and cosmology

Hello all.
Maybe I missed something. I love watching the science channel for hours on the weekends and learning about the universe and what not. I just don't understand it though. How do scientist know the temperature on Mars, or on Jupiter? How do they know the physics of outerspace. I can't think of all the examples that I've seen on various programs, but they start breaking down percentages of the gases that make up a foreign star, or something else, and I'm like how can you tell?

Wow that's a lot of questions all at once. I'll answer them as briefly as I could, but don't hesitate to ask if you need me to expand upon them.


"How do scientist know the temperature on Mars, or on Jupiter?"

Scientists determine the temperature of distant objects by measuring the amount of infra-red radiation emitted from the object. Every object that has a temperature above absolute zero emits infra-red radiation. That includes you and I and that is also the basis for Forward Looking Infra-Red cameras (those special black-and-white 'nightvision' you see in police or military videos).


"How do they know the physics of outerspace"

I'm not sure what you mean by this, but the physics out there is the same (as far as we can tell) as it is anywhere else in the Universe.


"they start breaking down percentages of the gases that make up a foreign star, or something else, and I'm like how can you tell?"

This is probably done via spectroscopical analysis. That is, they observe the spectral lines of the light reflected off the object and see if they can spot the tell-tale signatures of various elements. Back when this method was first discovered, they used a prism to split the light into it's constituent components and the 'signature" were dark bands within the spectra. You see, different stuff absorb different frequencies, resulting in the dark bands. These days it's all computer-aided.


Hopefully this helps you better understand those shows you watch

Plus, when it comes to measuring the temperatures on Mars, there's an "easier" (theoretically speaking) way: just stick a thermometer up there. All Mars landers (Viking 1 & 2, Pathfinder, Spirit, Opportunity) have carried thermometers and have been able to measure surface temperatures over the course of many years.

As for Jupiter, the Galileo spacecraft had an atmospheric probe that entered Jupiter's atmosphere and measured temperature, pressure and other parameters until it was crushed by the immense pressure.
en.wikipedia.org...