Current Events

  • Atmospheric CO2 Level Tops 400 ppm
    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm rep...Read more

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    Atmospheric CO2 Level Tops 400 ppm

    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well. The level of atmospheric greenhouse gases continues to increase, now over 120 ppm since the Industrial Revolution began. For more on the Keeling Curve, see http://keelingcurve.ucsd.edu/. Find out more about greenhouse gases and warming.
  • Massive Tornado Outbreak on Tornado Alley
    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Io...Read more

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    Massive Tornado Outbreak on Tornado Alley

    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Iowa, Illinois and Missouri. On May 20th, a massive tornado struck Moore, Oklahoma, devastating communities - destroying over 100 homes and hitting two elementary schools and a hospital - with many casualties and deaths. Our thoughts are with our friends and colleagues suffering from these storms. For more on the May 20th storms, see the NOAA Storm Prediction Center Storm Report.
  • Kansas Legislator Proposes Bill to Outlaw Sustainability Education
    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of ...Read more

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    Kansas Legislator Proposes Bill to Outlaw Sustainability Education

    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of sustainability. Here is a link to the one-page bill: http://www.kslegislature.org/li/b2013_14/measures/documents/hb2366_00_0000.pdf. See report on Bloomberg News.

If 2 cars are traveling at the speed of light and the one in the back turns on its headlights, would the car in front be able to see them? Why or why not?

It is not possible for objects with weight to travel the speed of light. So, let's ask a different question. If 2 cars are traveling nearly the speed of light and continue to get closer and closer to the speed of light, what happens when the car in the back turns on its headlights?

 If you look at the question from the point of view of someone in the front car, not much happens.  The distance between the cars does not change, so the light always takes the same time to catch the car in front.

 It's more interesting when one considers someone on the ground watching the cars go by.  In this case, two things happen.  First, from this person's point of view the distance between the cars shrinks the faster they go.  Second, the light takes longer to go from the rear car to the front car the faster they go. So as the cars approach the speed of light, the cars would become very, very close together and the light would take forever to get from one car to the next!


Submitted by J.(age 29, Texas, USA)
(November 21, 1997)



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