If you get enough hydrogen together in one place, gravity pulls it together to the point that the temperature and pressures are enough for fusion to occur. This is a star. But what happens when you don't have quite enough hydrogen? Then you get a failed star, like a gas giant planet or a brown dwarf.
Posted by
Scott on Apr 6, 2013 in
Astronomy,
Physics |
2 comments
Sure, our atmosphere protects us from a horrible Universe that's trying to kill us, but sometimes it prevents us from learning stuff too. Case in point, the atmosphere blocks highly energetic particles from reaching our detectors. But there's a way astronomers can still detect their influence: Cherenkov Radiation; the cascade of radiation that blasts out as a high-energy particle makes its way through the atmosphere, like a radioactive rainshower.
As we quickly learn with water, matter can be in distinct phases: solid, liquid, gas and plasma; it all depends on temperature. But why do different materials require different temperatures? And what's actually happening to the atoms themselves as the material switches phases?
Posted by
Scott on Apr 2, 2013 in
Astronomy,
Physics |
4 comments
It's mind bending to think about this, but the light in your house, and the house itself are really the same thing. Matter and energy are interchangeable. This was the amazing revelation made by Albert Einstein, with his famous formula: E=mc^2. This is the process that the Sun uses to turn hydrogen into radiation through fusion, and the terrible damage from a nuclear weapon.
Posted by
Joe on Sep 10, 2012 in
Forces,
Physics |
4 comments
An object at rest tends to stay at rest. An object in motion tends to stay in motion. Isaac Newton dismantled the traditional idea that objects would tend to slow down over time, and described the concept of inertia: the amount an object will resist changes in its motion.
Posted by
Joe on Jul 16, 2012 in
Physics |
0 comments
Last week we talked about energy, and this week we'll talk about mass. And here's the crazy thing. Mass, matter, the stuff that the Universe is made of, is the same thing as energy. They're connected through Einstein's famous formula - E=mc2. But what is mass, how do we measure it, and how does it become energy, and vice versa.
