Automobile engines tuned too lean and hot can form oxides of nitrogen - basically combining the oxygen and nitrogen from air. If it helps the above explanation, there is an analog of these nuclear processes in a common chemical process. one direction some of that energy can go is into the creation of heavier atoms. The reason the heavier/radioactive elements were created in the first place is that the conditions in a supernova involve extremely high energies. It takes little energy to initiate a decay which releases energy. This is why they have a tendency to decay. Some also exist in shallow potential wells. heavier elements have more mass (and more energy) bound up in than the sum of the lighter elements which fused to create them. This is why these processes only occur inside stars.Д«eyond iron, the situation changes. a lot of energy has to be put into a given nuclear reaction before it will occur, even though the reaction may release more energy than was input. Most elements also exist in a sort of potential energy well which makes them stable. This release of energy allows the process to proceed. This can occur because there is a general progression from hydrogen up to about iron where heavier elements have less energy bound up in them (less actual mass) than the sum of the lighter elements which fused to create them. Stars release energy from nuclear fusion of elements starting from hydrogen, then helium, and continuing through progressively heavier elements. Radioactive elements are formed naturally in any of several ways: in supernova explosions, from the radioactive decay of other elements, and by being struck by particles such as neutrons. So radon only lasts a few days before it decays so it shouldn't be on Earth, except that we do detect it and so the only explanation is that it was newly created, via radioactive decay. The radiation is stopped by the rock, so this isn't a problem, but the gas can leak into the house and decay in the rooms, exposing the inhabitants to sometimes high levels of radiation if there isn't enough ventilation.

Radon can build up in houses where the rock below contains traces of uranium and thorium, but this decays to radon. Its most stable isotope, $^$, has a half-life of 3.8 days, so the only way this stuff could be on Earth is if it was just created. Radon is a radioactive gas that isn't naturally found on Earth except that it is a decay product of uranium and thorium. It's called Cherenkov radiation ( ) so we can see and detect radiation from radiative decays, but is the energy coming from a radioactive decay? You can also 'see' the radiation if the particles move faster than light would move through that medium.

An example of this detecting radiation is shown in this video here: We can detect this using a device called a geiger counter. The radiation can take various forms such as a helium nucleus, a photon of light, an electron or even an anti-electron (called a positron). The difference in energy is radiated away. When a nucleus decays it moves from a higher energy state to a lower energy state. Probably the best way to observe radioactive decay is to look for the radiation that is emitted.

Half life in real life