Flying apart

The New York Times today provided an admirably brief and somewhat clear explanation of a raging scientific controversy.  After reading the article, I will try to condense the information even further, providing only that information you need to know for polite cocktail party conversation with other non-scientists.

Dropping the information contained in any one of these bullet points will impress your audience. If you're pressed for more details, just smile, waggle your eyebrows, and wander off in search of another drink.

• The universe is expanding, and the farther away a star or galaxy is from us, the faster it appears to be moving away from us.


• Hubble's constant is a measurement of how quickly the universe is expanding. 


• Hubble's constant is a ratio between two numbers: the difference in distances from earth of two objects and the difference in speeds away from earth at which those two objects are traveling.


• Since 2001, Hubble's constant has been calculated at various figures between 67 and 72.  This means that for every parsec farther away from earth one looks, objects appear to be traveling somewhere between 67 to 72 km/sec faster.  (A parsec is an astronomical measurement equal to about 3.3 million light years.)


• These varying values for Hubble's constant have been calculated in different ways, from differing data.


• Until recently, these measurements of Hubble's constant all fell within the margins of error for each..


• Now, they don't. The precision of measurements has improved. The discrepancy may seem small, but after a few billion years of increasingly rapid expansion, it makes a difference.


• To explain the discrepancy, it may be necessary to amend the cosmological "standard model" of the universe.  Either by assuming the existence of a new, fourth form of neutrinos, or by replacing the mysterious "black energy" of the standard model with a more powerful "phantom energy."


• If the universe does, in fact, contain the so-called phantom energy, it would imply that the universe will eventually be expanding so fast that individual atoms themselves will be ripped apart by the expansion.  This spectacular event, called the "Big Rip," would occur several billion years from now.


• Physicists have felt recently that cosmology was getting boring.  Now they're excited.

I think this is pretty interesting, as well.  However, even if we have more forms of neutrino than hitherto suspected, or even if we see the "Big Rip" coming down the pike, it's safe to conclude that these revelations will not affect the stock market, the next presidential election, or the amount of money in your 401k plan.

So, enjoy thinking about the Hubble constant, or not.  Unless you're a physicist, it's all a matter of personal taste.

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Photo taken from New York Times article.