Is the Universe Too Dangerous for Life?

DNA_orbit_animated_static_thumbIt may be the biggest question in science: does life exist elsewhere in the universe?

For those who hope the answer is “yes”, the recent harvest of exoplanets by NASA’s Kepler Space Telescope has been hugely encouraging. As of early 2015, in the small slice of sky under its exacting gaze, Kepler has found at least a thousand extrasolar planets, a handful of which might be rocky Earth-sized planets in the so-called ‘habitable’ zone where liquid surface water may exist. Extrapolating Kepler’s results, astronomers estimate our Milky Way galaxy alone might hold some 10 billion Earth-like planets. With that much real estate, complex or even intelligent life must have formed on at least some of these planets, right?

Well, maybe not. In a sobering paper published late in 2014 in the prestigious Physical Review Letters, astrophysicists Tsvi Piran and Raul Jimenez argue that most planets in the universe have been wracked by frequent galactic-scale environmental catastrophes that could destroy nascent life more complex than a single-celled organism.

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Birth of New Planets Around HL Tauri

HL Tauri (credit: ALMA/NRAO)

HL Tauri (credit: ALMA/NRAO)

The scientists and engineers at the Atacama Large Millimeter Array (ALMA) in northern Chile have been busy testing and calibrating this magnificent new observatory. Last week, on November 6, 2014, they released a test image which ranks as one of the most astonishing astronomical images ever captured. It shows the formation of a new planetary system out of a disk of gas and dust surrounding a new star. One ALMA scientist said, “This one image alone will revolutionize theories of planet formation”.

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The Lazy Person’s Guide to Dark Matter, Part 1

Let’s continue our occasional series on the basics of cosmology with a look at dark matter, an elusive substance which enabled the formation of the first galaxies, helps govern the large-scale structure of the universe, and which very likely is passing through your body right now completely unnoticed.  In this article, we look at what dark matter is not. In the next, we examine a few ideas about what dark matter might be.

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The Stardust Revolution

stardustPolitical revolutions happen quickly and, as King Louis XVI of France discovered, when you’re in the middle of one, chances are you’re going to know about it.

Scientific revolutions, by contrast, are more gradual affairs. The Copernican Revolution, which displaced the Earth from the center of the universe, began after Copernicus’ death in 1543.  His insight was disputed or ignored for decades until Galileo and Kepler in 1610 and Newton in 1687 laid its observational and theoretical foundation.

In a way, the Darwinian revolution was even slower. The idea that life on Earth evolves through a gradual change in characteristics over successive generations was first published, to widespread ridicule, in 1859. Some 150 years later, evolution is now on as solid a scientific footing as Einstein’s theories of relativity, but it remains controversial in some parts of the so-called modern world.

According to science writer Jacob Berkowitz, we’re in the middle of another slow-motion scientific revolution, one that’s profoundly changing our view of life on Earth and its possibility elsewhere in the cosmos. He calls this revolution– and his new book about it– the The Stardust Revolution .

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Kepler’s Laws

Once Kepler got his hands on Tycho’s measurements, he worked diligently to make sense of the data and to develop a solid framework for the workings of the solar system.  He succeeded.  Working for more than a decade, crunching numbers with pen and paper, he laid out three simple mathematical laws that account for the motion of the planets.   Kepler’s Laws were descriptive, so they didn’t explain the physical basis for celestial motion.  That task fell to an even more astute mathematician: Isaac Newton.  But “Kepler’s Laws” are rigorous enough to account for most planetary motion, and are still taught to high-school and college students all over the world.  Here’s what they’re all about…

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