Friday, November 30, 2012

Q: Event A has a probability of 70% of happening within the year and event B, 40%. The events are independent and uniformly distributed through the year. What is the probability that they will occur within 3 months of each other?

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There is more than one way to answer this question! The ambiguity comes down to exactly how we interpret the statement that "Events A...
2 comments:
Monday, October 29, 2012

Q: What is it like to have the process of video encoding or transcoding bring you to tears?

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In 2005, we built a system to do the first amateur ATSC HDTV broadcasts. We broadcast MIT sporting events and the January "Integration ...
4 comments:
Sunday, October 21, 2012

Q: What are France's most remarkable contributions to the modern world?

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How about: Aviation (Montgolfier brothers, Robert brothers) Moving pictures (co-invented by the Lumière brothers) Electromagnetism (many...
6 comments:
Friday, October 5, 2012

Q: How many unique Tweets can ever be posted?

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At least   (a number with 1,264 decimal digits), using the contents of the tweet alone. Plus there is all the metadata, which probably adds ...
2 comments:
Thursday, August 30, 2012

Q: Why is the SI second defined as 9,192,631,770 periods of the transition between two states of cesium-133?

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In 1895, the astronomer Simon Newcomb published his "Tables of the Sun," based on observations of the sun's position from 1750...
8 comments:
Saturday, August 25, 2012

Q: If one day is not exactly 24 hours and is in fact 23 hours, 56 minutes, shouldn't the error add up, and shouldn't we see 12 a.m. becoming noon?

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You're right that a "sidereal" day is about 23 hours, 56 minutes, 4 seconds. But this is not a day in the everyday sense. A ...
79 comments:
Tuesday, July 24, 2012

Q: Why don't we see green stars?

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Stars are black bodies in thermal equilibrium ( http://en.wikipedia.org/wiki/Black-body_radiation ). Their spectrum depends only on their te...
1 comment:
Friday, May 4, 2012

Q: What is the safest, simplest, and most effective method to anchor an average-size sailboat?

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There is technique (and many strong feelings) to anchoring, but I don't think there are any great secrets beyond what is taught in saili...
1 comment:
Friday, April 20, 2012

Q: Does all "white noise" sound like the same hiss?

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The answer is no: not all white noise sounds alike! White noise can sound like "hissing" of a shortwave radio or it can sound li...
3 comments:
Thursday, February 9, 2012

Q: What were some surprising court decisions?

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American Council for the Blind v. Boorstin, 644 F. Supp. 811 (D.D.C. 1986), holding that the First Amendment required the U.S. Government to...
2 comments:
Thursday, February 2, 2012

Q: What are the most impactful inventions created in Boston?

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I think the telephone is probably the all-time top Boston invention, but also these: 1802 -- Modern navigation -- Bowditch 1886 -- Ma...
2 comments:
Wednesday, January 11, 2012

Q: If I mix 700nm (red) light and 400nm (green) light, is the result a color that can't be made by a single wavelength?

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The answer is yes -- if you mix light from a laser (monochromatic light) at 700 nm with another laser at 400 nm, the resulting radiation wil...
9 comments:
Sunday, October 16, 2011

Q: How does an investigative reporter get started?

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Many investigative reporters got where they are by starting as beat reporters. This is a good way to get story ideas and familiarity with an...
Saturday, July 2, 2011

Q: What are the most iconic images from astrophysics?

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Orbital decay of a binary pulsar compared with the prediction of general relativity. This won the Nobel Prize in physics in 1993. Powe...
1 comment:
Saturday, June 18, 2011

Q: Is there any technical data available to support claims of “best HD picture quality” when choosing a satellite, cable or IPTV service provider?

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I  have done a real-time comparison between the HDTV signals transmitted by local broadcasters in the Boston area (NBC, ABC, CBS) over broad...
4 comments:
Tuesday, May 31, 2011

Q: What was the first digital newspaper in the world?

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This is a provocative question, and it really depends on what you mean by a digital newspaper. Arguably any written language formed out of...
2 comments:
Saturday, May 28, 2011

Q: Is the Charles River safe to swim in?

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It depends -- on the day, your location in the river basin, and who you are. The short answer is that if you are young and have a robust i...