Asteroids strike, planets collide, black holes blast out death rays, volcanoes erupt and ice engulfs the planet. These are the universe’s weapons of extinction. They’ve happened before - wiping out entire species, and they will happen again. Are we next?
2014 • Astronomy
How does light escape from the sun? We take a journey from the centre of the sun, following the path of light. We witness its fiery birth from in the core, its 430,000 mile battle against gravity and magnetism, and its escape from the solar surface.
2014 • Astronomy
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.
2015 • Astronomy
Orbits are the dynamics that drive the universe. From the smallest asteroid to the largest super-cluster, everything in the universe is in orbit. We owe our very existence to the stability of earth's orbit — it gave us life and keeps us safe. But we are the freaks. Everywhere else we look we find orbits are chaotic, unstable, and violent. Beyond our solar system we find planets that are blow-torched, stars that eat each other, and black holes that destroy everything in their path. Yet on the very largest scale, orbits are also a creative force. clashing galaxies give birth to new stars and new worlds. on the galactic scale orbits even construct the fabric of the universe itself.
2012 • Astronomy
The first second of the Universe, the creation of everything when space, time, matter and energy burst into existence. It is the most important second in history, which seals the Universe's fate and defines everything that comes after - including us.
2014 • Astronomy
Recent discoveries could explain how supermassive black holes grow so big, one of the universe's most mysterious questions. Neither dark matter nor cannibalism can fully explain these monsters, but the latest science might finally provide an answer.
2016 • 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.
2017 • Astronomy
If a massive asteroid collides with earth, it could end life on our planet as we know it; new discoveries and cutting-edge tech reveal just how close we are to apocalypse and what it would take for the world's leading space agencies to stop it.
2020 • Astronomy
Dead stars may be the key to understanding the cosmos. New research proves white dwarfs are one of the driving forces of our universe. They eat planets, they flare out in high-energy light Have scientists finally discovered how these small stars could be such massive galactic players?
2021 • Astronomy
For decades, scientists have dreamed of finding life on Mars. But despite their best efforts, no signs of life have been found. Could that be about to change? This is the story of the scientists and engineers behind Perseverance: the rover that could change our view of Mars forever.
Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into gas, forming the long tail, and also releases dust that forms a different tail. We’ve visited comets up close and found them to be lumpy, with vents in the surface that release the gas as ice sublimates. Eons ago, comets (and asteroids) may have brought a lot of water to Earth -- as well as the ingredients for life.
The Moon has drawn out our sense of wonder since before we were fully human. Where did it come from? What secrets are written in its rocks? For most of our history, its story was cloaked in myth and mystery. Only now are the vivid details coming into focus.
Sagan discusses comets and asteroids as planetary impactors, giving recent examples of the Tunguska event and a lunar impact described by Canterbury monks in 1178. It moves to a description of the environment of Venus, from the previous fantastic theories of people such as Immanuel Velikovsky to the information gained by the Venera landers and its implications for Earth's greenhouse effect. The Cosmos Update highlights the connection to global warming.