Radioactivity is about certain elements – or variants of them – in course of time decaying.  Most such which has been found have never been observed to decay.  A smaller fraction has and then emit ionising radiation.  The faster they decay the more they emit.  It can be in the form of gamma rays or different types of particle radiation.  Please note that the danger is about the dose one gets.  It is possible to protect oneself by minimising exposure.  Different types of radiation can also be stopped by certain materials.

Before nuclear reactions were discovered there were troubling problems in science.  Scientists for example did not knew how the Sun produces its energy.  The best explanations they had was it doing it by shrinking.  Trouble is, it is only enough to keep the Sun shining for at most 40 million years.  Geological research indicated the Earth to be at least hundreds of millions of years old.  How would one solve this contradiction?

Radioactivity was discovered by chance.  Henri Becquerel placed a piece of uranium ore on top of a photographic plate.  Later he discovered the photo had got a large black spot.  When it was investigated how it got that way it was discovered uranium was radioactive.  Several radioactive elements were discovered by a married couple he knew.  These were Maria Skłodowska and Pierre Curie.  When they purified the elements they used then normal chemistry equipment.  They made no attempt to protect themselves against the substances they worked with.  Maria complained for Henry about her many hardly healed wounds.  Henri then suggested the radiation they researched could be dangerous.  She answered they took that risk which they should not have done.  After having moreover worked as an X-ray radiologist she eventually died from cancer.  Pierre would have done so too, if he had not died from a traffic accident first.

The discovery of radioactive decay made absolute dating possible.  The first dating of rock layers were done with chemistry equipment too.  The results of these came as a chock!  All of a sudden it turned out the Earth was ten times as old.  The geologists had as such been wrong but in the opposite way.  At the same time radioactivity meant there were more possible energy sources.  Maybe this could also explain how the Sun and the other stars produces their energy?  By then scientist knew all stars are suns.

It was initially uncertain if atomic energy could be used.  Many scientists doubted atoms could be splintered.  Then she did it!  Lise Meitner cleft the atom and proved it was possible.  This is called fission and can be done controlled or uncontrolled.  Atoms splintered in controlled processes can be used in nuclear power.  However, it did not become the matter to energy converter as many has imagined.  Fission only works for elements with a higher atomic number than iron.  Just a small part of matter the process converts into energy.  Hence the hard to solve problem of waste from nuclear power plants.  I think it is only Finland which has solved this problem by now.

Six years before the atom was first splintered atoms had been joined.  Mark Oliphant did it first.  This is called fusion and has periodically been overrated.  Unlike fission atoms are then merged into new.  It turned out it was this way which the Sun and other stars produce their energy.  Fusion works on all elements with a lower atomic number than iron.  (Nuclear processes as such stop after having produced iron.)  This process does not have the same waste problem as the nuclear power plants mentioned above.  Unfortunately, man-made fusion has not came to any practical use.  Those staying alive will see if it ever does.

Uploaded on the 12th of April 2024.