The only reason life on Earth is possible is because of our stable orbit around the Sun. Elsewhere in the Universe, orbits are chaotic, violent and destructive. On the largest scale, orbits are a creative force and construct the fabric of the Universe.
This episode concentrates on how the universe was made in the Big Bang and how scientists predict it could end similarly as it continues to expand. Several theories are covered including the "Big Crunch" where the universe shrinks back to its original size, and the "Big Chill" with the universe slowly freezing to death.
45m • Naked Science
All life on Earth needs water so the search for aliens in the solar system has followed the search for water. We examine the patterns in the ice on Jupiter's moon Europa, which reveal an ocean far below with more potentially life-giving water than all the oceans on Earth. But of all the wonders of the solar system forged by the laws of nature, Brian reveals the greatest wonder of them all.
Thanks to observations of galaxy redshifts, we can tell that the universe is EXPANDING! Knowing that the universe is expanding and how quickly its expanding also allows us to run the clock backwards 14 billion years to the way the universe began - with a bang.
13m • 2015 • Crash Course Astronomy
Life once existed on Mars, but a series of devastating mass extinctions have made present-day life nearly impossible. The latest science shows how Martian life keeps bouncing back as it transforms from a watery world like Earth into a desert planet.
42m • 2017 • How the Universe Works
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.
11m • 2015 • Crash Course Astronomy
There is a new kind of weather to worry about, and it comes from our nearest star. Scientists are expecting a fit of violent activity on the sun which will propel billions of tonnes of superheated gas and pulses of energy towards our planet. They have the power to close down our modern technological civilisation - e.g. in 1989, a solar storm cut off the power to the Canadian city of Quebec. Horizon meets the space weathermen who are trying to predict what is coming our way, and organistions like the National Grid, who are preparing for the impending solar storms.