Double stars are stars that appear to be near each other in the sky, but if they’re gravitationally bound together we call them binary stars. Many stars are actually part of binary or multiple systems. If they are close enough together they can actually touch other, merging into one peanut-shaped star. In some close binaries matter can flow from one star to the other, changing the way it ages. If one star is a white dwarf, this can cause periodic explosions, and possibly even lead to blowing up the entire star.
The Ship of the Imagination ventures on an epic voyage to the bottom of a dewdrop to explore the universe on the smallest scale and observe exotic life forms invisible to the naked eye. Then, host Neil deGrasse Tyson explains the neural network in our brains which determine our sense of smell and memory, and later, he travels deep beneath the surface of the Earth to discover the most mysterious particle we know.
This is the epic story of the stars, and how discovering their tale has transformed our own understanding of the universe. Once we thought the sun and stars were gods and giants. Now we know, in a way, our instincts were right. The stars do all have their own characters, histories and role in the cosmos. Not least, they played a vital part in creating us. There are old, bloated red giants, capable of gobbling up planets in their orbit; explosive deaths - supernovae - that forge the building blocks of life; and black holes, the most mysterious stellar tombstones. And, of course, stars in their prime, like our own sun. Leading astronomers reveal how the grandest drama on tonight is the one playing above our heads.
2012 • Astronomy
How do astronomers make sense out of the vastness of space? How do they study things so far away? Today Phil talks about distances, going back to early astronomy. Ancient Greeks were able to find the size of the Earth, and from that the distance to and the sizes of the Moon and Sun. Once the Earth/Sun distance was found, parallax was used to find the distance to nearby stars, and that was bootstrapped using brightness to determine the distances to much farther stars.
On July 14, 2015, the New Horizons spacecraft, one of the most advanced ever built, is scheduled to fly by Pluto to take the very first detailed images of the dwarf planet. After nine years and 3 billion miles, we will finally get a close look at this strange, icy world, but only if the craft can survive the final, treacherous leg of its journey, which could take it through a dangerous field of debris.
Artificial selection is one example, eyes another, of the well-documented and inescapable process of evolution--change in a population of species over time--by natural selection. These are some of the things that molecules do.