"A five tonne, 20-year-old satellite has fallen out of orbit and is expected to crash somewhere on Earth"

"Nasa says the risk to life from the UARS - Upper Atmosphere Research Satellite - is just 1 in 3,200."
…
"The 1 in 3,200 risk to public safety is higher than the 1 in 10,000 limit that Nasa aims for."


BBC

My baby's fooling around with a satellite

Researchers at the University of Edinburgh in Scotland constructed a computer model to create a synthetic galaxy with billions of stars and planets. They then studied how life evolved under various conditions in this virtual world, using a supercomputer to crunch the results.

In a paper published recently in the International Journal of Astrobiology, the researchers concluded that based on what they saw, at least 361 intelligent civilizations have emerged in the Milky Way since its creation, and as many as 38,000 may have formed. |CNN|

The obvious question is, if intelligent life is so plentiful, why can't we get alien channels on the TV? To clarify my thinking on this question, I did some back of the envelope math, which I'd now like to share with you.

Let's start with some assumptions. The Milky Way is about 10 billion years old, intelligent species are on the galactic scene for about 100,000 years, and civilizations are distributed roughly equally across time.

I can't justify any of those, but I can say something about the last two. Taking the last first, this makes the math easier. With regard to the other, in the current pulp sci-fi I'm reading the assumption is 50,000 years, but that seems parsimonious. My thought is: it took human kind about 100,000 years to get to radio and surely we'll destroy ourselves within the next 100 milennia.

Given all that, and working with the upper bound of 38,000 civilizations, it turns out that you'd expect that there is an intelligent civilization broadcasting about 1/3 of the time.

What does all this mean? In a word, that even in light of this finding it should be no surprise that we remain mired in terrestrial programming.

Mars

At a NASA news conference this afternoon, a team of scientists led by Michael Mumma of the Goddard Space Flight Center announced the discovery of plumes of methane emanating from the surface of Mars during the planet’s late spring and early summer…

The only way to learn more about these plumes may be to go and physically investigate them, she said. Observing them from Earth—or even from Mars orbit—probably won’t reveal whether there are microbes beneath the surface. “We’re going to have to get down where they live,” she said. The Mars Science Laboratory, a new rover set to launch in 2011, carries instruments that could investigate below the planet’s surface—but most likely not deep enough. If microbes do exist on Mars, Mumma said, they could be buried more than a kilometer down. That would require a whole new plan, including technology that doesn’t yet exist.

You can only learn so much by observation and remote drones.

We need to get there A.S.A.P and have our minds blown and axioms shattered.

I’ll never shut up about this. | grinding |

Amen.

Monday morning outer-space thread

Three Chinese astronauts made a jubilant return to Earth on Sunday after successfully completing the country's first-ever spacewalk, an event the premier said was "a stride forward" in China's space history. | link |

and

Trailing an orange pillar of flame, a rocket designed and built by a company founded by a Silicon Valley billionaire became the first privately developed, privately financed rocket to reach Earth's orbit today, potentially blazing a much cheaper pathway to space. | link |

and, by contrast

Those who keep tabs on NASA's fortunes worry that the agency's plan to return Americans to the moon in a decade won't amount to more than a cluster of plywood frames in a hangar. As NASA marks its 50th anniversary Wednesday, space experts say NASA is adrift, its future disturbingly murky. | link |

Dumb Game 4th of July Hedgehog Launch!

This game is really, really fun. My advice is to start by upgrading your goggles. In other news, in searching for this game, I learned about "Hedgehog Space."

For any cardinal number K, the K-hedgehog space is formed by taking the disjoint union of K real unit intervals identified at the origin. Each unit interval is referred to as one of the hedgehog's spines. A K-hedgehog space is sometimes called a hedgehog space of spininess K.

Word. 

"Pioneer anomaly" joined by the "flyby anomaly"

For some time, the Pioneer probes hurtling out of our solar system seem to be slowing down without explanation. Now it seems that some other probes, when flying by the earth, seem to be going faster:

In five of the six flybys, the scientists have confirmed anomalies.

"I am feeling both humble and perplexed by this," said Anderson, who is now working as a retiree. "There is something very strange going on with spacecraft motions. We have no convincing explanation for either the Pioneer anomaly or the flyby anomaly."