Follow Friday & Weekly Stumbles For 2010-11-05

This week I recommend to follow @CosmoWatch for lots of interesting tweets about astronomy and space exploration. For more Twitter follow suggestions see our astronomy list @TheAstroBlog/astronomy

Weekly Stumbles:

We could be running out of time to send astronauts to Mars
America’s current plans for human space exploration seem horribly slow, considering we won’t leave Earth’s orbit until 2025 and won’t reach Mars until 2035. Worse than that, solar radiation spikes could keep us grounded for decades more. The Sun emits a steady stream of potentially deadly cosmic radiation. As long as humans remain within the Earth’s atmosphere, the threat posed by this radiation is practically nil, but any extended trips into deep space require careful shielding to protect astronauts from the threat of radiation sickness or cancer. The exact levels of radiation vary depending on the severity of solar activity, which falls into a number of predictable cycles.

Asteroids Point to a Water-and-Organics-Rich Universe
This past April, two teams of researchers discovered the first-ever evidence of water ice and organic molecules riding around the solar system aboard an asteroid. Today, the same group has reported that it has found ice and organics on a second, larger asteroid as well, a finding that suggests water ice and organic molecules may be common passengers aboard asteroids throughout the solar system.

The Universe After Hubble: New Mysteries of the Cosmic Web
Astronomers anticipate that NASA’s James Webb Space Telescope -the largest space-based observatory ever constructed- will reveal planets in the making and identify the universe’s first stars and galaxies, things no telescope — not even Hubble — has ever shown them before. At larger scales superclusters seem to blend into chains and filaments that span vast distances forming a cosmic web that seems to be the foundation on which the universe is built. Webb will explore how stars, young galaxies and dark matter worked to create large-scale cosmic structure.

Mitigating Asteroid Threats Will Take Global Action
During the past 24 hours, the Earth has been hit by about a million small meteoroids – most of which burned up in the atmosphere as shooting stars. This happens every day. And occasionally – once every 10,000 years or so — a really big asteroid (1 km in diameter or larger) comes along and smacks Earth with an extinction-level impact. That idea might cause some of us to lose some sleep. But in between are other asteroid hits that occur every 200-300 years where a medium-sized chunk of space rock intersects with Earth’s orbit, producing a Tunguska-like event, or worse.

Saturn’s Rings Mimic Behavior of the Milky Way
Images of Saturn’s most massive ring, the B ring (above), captured by NASA’s Cassini spacecraft have revealed the answer to a long standing mystery of why one of the most dynamic regions in Saturn’s rings has such an irregular and varying shape: the rings, scientists discovered, are behaving like a miniature version of our own Milky Way galaxy. This new insight, garnered from images may answer a second long-standing question: the cause of the bewildering variety of structures seen throughout the very densest regions of Saturn’s rings.

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