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Archive for the ‘Astronomy’ Category

Fact vs. Fiction

I was looking around on the internet last night, searching for ideas for my next column when I found an article titled “50 Interesting Science Facts”. One of the items it listed was “If our Sun were just [an] inch in diameter, the nearest star would be 445 miles away.” Wow, I thought, that really illustrates the vastness of space pretty well. Maybe I could use it somehow. But I was a bit suspicious because the comparison didn’t use the metric system, and we all know that any scientist worth their NaCl uses the metric system! Also, it had a typo—the word “an” was omitted before the word inch. In my day-job I do a lot of proofreading and copy editing so typos always make me suspicious. What the heck, I thought, lets run the numbers and see if it checks out.

According to NASA and Wikipedia, the diameter of the Sun is about 1,390,000 km, and the nearest star to us, Proxima Centauri, is 4.22 light years away, or 39,900,000,000,000 km (written as 3.99 x 1013 km in scientific notation). So if we divide the latter by the former, we find that the ratio of distance to diameter is 28,700,000 : 1, so if the Sun were one centimeter in diameter, the nearest star would be 287 km away. Sounds about right, but lets convert to American units to be sure. The number of inches in a mile = 12 in/ft x 5,280 ft/mi = 63,360 in/mi. So if we take our distance to diameter ratio, 28,700,000 and divide by 63,360 in/mi we find that, in fact, if the Sun were one inch in diameter the nearest star would be 453 miles away. Our “interesting fact” is off by eight miles, or about three percent! If they had just written that it would be about 450 miles away I would have no problem, but when you present information to three significant digits then it should be accurate to three significant digits.

But now things get even more fun, because on the internet an incorrect “fact” gets propagated far and wide rather quickly. Doing a Google search on “If our Sun were just inch in diameter, the nearest star would be 445 miles away.” it turns out that I wasn’t the only one that thought it was an interesting fact, just the only one to check it. There were over 3,000 results that had the same incorrect information, and all but nine of them had kept the typo as well. Even a monkey can copy and paste I guess!

Google returns 3,010 search results for “If our Sun were just inch in diameter, the nearest star would be 445 miles away.”

Good science requires attention to detail and willingness to question everything, and I want to encourage my readers to take the time to check details and ask tough questions. So instead of a quiz this week I have a challenge instead: find your own scientific “fact” that is incorrect and report it to me, either by e-mail (douglasclark@sbcglobal.net) or through my Facebook page (keyword weeklysciencequiz). If you find something I’ll give you credit on an upcoming article. Happy hunting!

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Located in the foothills of the San Gabriel mountains in Pasadena, JPL is NASA’s research laboratory that is managed by Caltech. JPL’s primary mission is space exploration using robotic spacecraft. This past weekend I had the good fortune of being able to attend JPL’s annual open house event, and I was pleasantly surprised by how many people were there, with lines of people waiting patiently to get into one of the 20+ exhibits. We were able to view 3D stereo images of Mar’s surface as well as watch a short 3D movie about the Earth. We were able to see how NASA missions are using JPL’s infrared imaging technology to create incredible photos of distant stars and galaxies. We also saw how exoplanets are being discovered at an ever-increasing pace in an attempt to find other Earth-like planet in the cosmos capable of supporting life.

The Martian Science Laboratory rover (right) on display at JPL and in comparison with the Mars Exploration Rover (left) and Sojourner rover (center).

There were several rovers on display, the most-impressive being the full-scale next-generation Mars Science Laboratory (MSL) rover. Named Curiosity, the MSL is scheduled to launch this fall and make a precision landing on Mars in August, 2012. Curiosity, with its array of scientific instruments, will be able to help assess whether or not Mars either now or at some time in its past is able to support microbial life forms.

2011 is a very busy year for JPL. Besides Curiosity, in June JPL’s Aquarius satellite will be launched. Aquarius will map the salinity of the Earth’s ocean surfaces. This information will be used to improve our understanding of the oceans’ role in the water cycle by tracking how fresh water is exchanged between the atmosphere, sea ice and oceans. By measuring changes in ocean surface salinity, as well as melting ice and river runoff, Aquarius will provide new information about how freshwater moves around our planet which will help improve computer climate models as well as our understanding of worldwide ocean currents.

In August, NASA will launch JPL’s Juno explorer which will, by 2016, begin orbiting Jupiter to study the planet’s composition as well as gravitational and magnetic fields, and polar magnetosphere. Juno will look for clues about how Jupiter was formed: whether it has a rocky core, how much water is present deep within the atmosphere, and what the mass distribution is within the planet. Juno will also study Jupiter’s violent storms where winds can hit speeds of 600 km/h. With all the activity going on at JPL, we can be assured of many new discoveries in the near future which I look forward to covering in more detail as they occur.

An artistic conception of Juno orbiting Jupiter.

1) True or false: JPL is managed by NASA.

2) Curiosity is the name of JPL’s ____________.

a) Mars Science Laboratory b) Earth satellite. c) Mars Exploration Rover d) Jupiter satellite

3) True or false: JPL’s primary mission is to explore space with robotic-controlled spacecraft.

4) The Aquarius satellite will help us understand ___________.

a) exoplanets b) Earth’s climate c) the salinity deep under the ocean surface d) Jupiter’s atmosphere

5) Juno will explore __________.

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