Life behind the Stars

The northern lights, also known as the aurora borealis, are a light phenomenon that occur in the northern polar region. The aurora is caused by cosmic rays.

The rays causing the aurora borealis have also had a significant effect on the evolution of life on Earth, but they bear a threat. How do these rays impact our climate? And what are the consequences for life on Earth? We don't see or feel them and yet they surround us all the time. Particles from outer space constantly hurtle into our atmosphere. The low-energy cosmic rays of the sun produce one of the most beautiful natural phenomena on Earth: auroras. The aurora borealis or northern lights in the Northern Hemisphere and the aurora australis in the Southern Hemisphere light up the sky. As astrophysicist Pavel Motloch explains, "what happens to these cosmic rays depends on how much energy they carry. The low-energy rays coming from the Sun are mostly shielded from the Earth's magnetic field. So they follow the field lines of the magnetic fields up in the North and South Pole regions, where you can see them as the magnificent northern lights. But there are also the high-energy cosmic rays, which just go through the magnetic field and don't care about it at all." Most of them are protons, which generate immense energy as they accelerate. For decades, astrophysicists around the world have been puzzling over where these particles come from and how they generate so much energy. Cosmic rays can cause genetic changes, and biologists see them as an important factor in evolution - without them, the diversity of species we see today wouldn't exist. But cosmic rays would be deadly without protection. Fortunately, our planet has effective shields against the constant flow of particles from outer space in the form of a magnetic field and the Earth's atmosphere. Its magnetic field acts as a radiation blocker, and the Earth's atmosphere also absorbs a lot of the particles. In fact, only a small amount of radiation reaches the Earth's surface at all. Every 50 years a supernova explodes, flooding the Milky Way with cosmic rays. At the Pierre-Auger Observatory in Argentina, a groundbreaking international experiment is investigating ultra high-energy cosmic radiation. The filmmakers travel to research centers in Spain, Argentina and Switzerland to uncover its mysteries.

Related Links
Beauty in the Heavens

Asteroids: The Good, the Bad and the Ugly

Famed for their ability to inflict Armageddon from outer space, asteroids are now revealing the secrets of how they are responsible for both life and death on our planet. Armed with an array of powerful telescopes, scientists are finding up to 3,000 new asteroids every night. And some are heading our way. But astronomers have discovered that it's not the giant rocks that are the greatest danger - it's the small asteroids that pose a more immediate threat to Earth. Researchers have explained the photon propulsion that send these rocks across space, and have discovered that some asteroids are carrying a mysterious cargo of frost and ice across the solar system that could have helped start life on Earth.

Related Links
Catastrophe - Asteroid Strike
Asteroid Impacts with Earth

Astrobiology

Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe: extraterrestrial life and life on Earth. This interdisciplinary field encompasses the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry, laboratory and field research into the origins and early evolution of life on Earth, and studies of the potential for life to adapt to challenges on Earth and in outer space. Astrobiology addresses the question of whether life exists beyond Earth, and how humans can detect it if it does.
(from wikipedia.org)

Related Links
Astrobiology and the Search for Extraterrestrial Life
Finding Life Beyond Earth