How did ancient civilizations make sense of the cosmos, and what did they get right?


Known as the cosmic microwave background radiation, many researchers consider it the strongest evidence for the Big Bang. If this future seems dark and depressing, take comfort in knowing that every earthling will have died long before we have to worry about it. In fact, on this timescale of trillions of years, even the existence of our entire species registers as but a brief ray of sunlight before an infinite winter of darkness. Starting in the 1950s, progress in atomic physics led to accurate modeling of stars’ surface layers. Simultaneously, detailed knowledge of the nuclei not just of hydrogen and helium atoms but also of the rest of the elements allowed scientists to calculate which nuclear reactions dominate at different stages in a star’s life. Astronomers came to understand how nuclear fusion creates an onion-skin structure in massive stars as atoms successively fuse to build heavier and heavier elements, ending with iron in the innermost, hottest layer. Soon after Hubble realized that the universe was bigger than many had thought, he found that it was still growing.

Musician and physicist Stephon Alexander is the author of The Jazz of Physics and Fear of a Black Universe

And by a googol years into the future , Hawking radiation will have killed off even thesupermassive black holes. “Just” a couple trillion years from now, the universe will have expanded so much that no distant galaxies will be visible from our own Milky Way, which will have long sincemerged with its neighbors. Eventually, 100 trillion years from now, all star formation will cease, ending the Stelliferous Era that’s be running since not long after our universe first formed. When the history of science gets written, this amazing progress will be acclaimed as one of its greatest triumphs—up there with plate tectonics, the genome and the Standard Model of particle physics. Exoplanet research is only 25 years old, and serious work in astrobiology is really only starting.

Aristarchus’ work was eventually rediscovered and revived by later astronomers, most notably Copernicus, in the 16th century. Thus, Aristarchus proposed that the Sun was at the center of the universe. The Earth and other planets were believed to revolve around the Sun. Aristarchus’ conclusions were based largely on his observations of the heavens.

Euclid telescope releases first awe-inspiring images in dark universe hunt

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Physicists began changing the assumption that the universe was static and unchanging. In 1922, Alexander Friedmann introduced the idea of an expanding universe that contained moving matter. Its first target will be a “supermassive” black hole at the center of our galaxy. At the Gran Sasso underground laboratory, deep beneath the Apennine Mountains of central Italy, scientists are keeping watch over a giant tank filled with 3.5 metric tons of liquid xenon. Their hope is that exotic particles from deep space will whiz through the liquid, emitting a telltale signal. But scientists hunting for so-called “dark matter” have learned to be patient. The standard model has been successful enough that it makes sense for most astrophysicists to stick with it.

The equant was a point located away from the center of the deferent but symmetrically opposite to the epicycle. The concept of the epicycle and epicycle allowed for explaining the irregular movements of the planet as can be observed from Earth, such as retrograde motion. Hipparchus made further advances in trigonometry that were used to improve the accuracy of astronomical measurements. He innovated techniques that were foundational in calculating the distances and sizes of celestial bodies. The first comprehensive star catalog was compiled by Hipparchus and was called the “Hipparchus Catalogue.” The catalog included the positions and magnitude of around 850 stars.

The problem is that sets with infinite members can be equal in size to their subsets. Craig uses the illustration of a library with an infinite number of books, half of which are red. Half of infinity is still infinity, so half of infinity is not actually smaller than infinity. This might make sense theoretically, but Craig claims problems arise when applying it to reality. It would mean the set of red books ‘X’ is apparently smaller than the set of all the books ‘Z’, and yet paradoxically is also equal in size, since both are infinite.