In March 1903, the Curies demonstrated that radium continuously emanates a surprising amount of heat. Then, the 1900s dawned, and radioactivity was discovered.
Evolution had come thus far it didn't have time to go much further.Īs the 1800s closed, there was little room for grand optimism regarding humanity's far-flung future on Earth. Expressing the general mood in 1893, one Irish astronomer pronounced that our "Sun had already dissipated about four-fifths of the energy with which it may have originally been endowed". Estimates on the deadline varied between physicists, but by the century's closing decades the community converged upon the very low tens of millions.įor many thinkers of the period, it was the ratio of "time ahead", to "time spent", that proved particularly depressing. After this, he declared, Earth will be sterilised by cold. In 1854, it was forecast by Scottish mathematician Lord Kelvin that there were only 300,000 years left. Physicists had started calculating how long the Sun could continue to shine for, but because they falsely believed that it generates heat by collapsing under its own weight, their estimates were far too short. The problem was that, by Victorian times, science's judgement on how much future lay ahead was somewhat austere.