All posts for the month September, 2007

Lookin’ fer Pulsars!

Pulsars are spinning neutron stars (Image by Bill Saxton, NRAO/AUI/NSF)

Pulsars are spinning neutron stars (Image by Bill Saxton, NRAO/AUI/NSF)

Pulsars are big, nasty, radio-noisy beasts in the cosmic zoo. They are what’s left over after a massive star (say one that is at least eight times more massive than the Sun) explodes as a supernova. Some of the star’s body (what hasn’t been blasted out to space) falls back in on itself in a seething mass of crushed neutrons. They’re superdense and they spin. As they whip around many times per second, they send out beams of radio waves that sweep across our field of view like the light from a lighthouse. We catch their beams as pulses of radio waves; hence the name “pulsar.”

A group of astronomers who study these strange stellar animals has put together a project for high school students and their teachers to participate in searching out pulsars in our galaxy. The students and educators will join astronomers on the cutting edge of science under a program to be operated by the National Radio Astronomy Observatory (NRAO) and West Virginia University (WVU), and funded by the National Science Foundation (NSF). The program, called the Pulsar Search Collaboratory, will engage West Virginia students and teachers in a massive search for new pulsars using data from the Robert C. Byrd Green Bank Telescope (GBT).The GBT has discovered more than 60 pulsars over the past five years, including the fastest-rotating pulsar ever found, a speedster spinning 716 times per second.

Student teams will receive parcels of data from the GBT and analyze the data to discover pulsars. To do this, they’ll learn to use analysis software and recognize radio interference from Earth-based technologies that can contaminate the data. Each portion of the data will be analyzed by multiple teams. Of the 1,500 hours of GBT observing data in the project, all taken during the summer of 2007, some 300 hours is reserved for analysis by the student teams. This reserved data set is expected to include tens of new pulsars and about 100 known pulsars. It’s highly possible that each student in the project could discover one of these cosmic beasts for themselves. Think of how THAT will look on a college application form!

…Really COOL Stuff… from Stars

In the Star Trek: The Next Generation episode called “Home Soil,” the crew of the starship Enterprise run into a life form that, when they finally figure out a way to communicate with it, calls the humans “ugly bags of mostly water.” It’s a great line, but it’s also true: we ARE mostly water.

In fact, if you break down the elements in our bodies by how much there is of each one, you get this list:

  • 65% oxygen
  • 18% carbon
  • 10% hydrogen
  • 3% nitrogen
  • 1.5% calcium
  • 1.0% phosphorus
  • 0.35% potassium
  • 0.25% sulfur
  • 0.15% sodium
  • 0.05% magnesium
  • A mix of copper, selenium, fluorine, chlorine, molybdenum, iodine, cobalt, manganese, and iron that comes to about 0.70%
  • Another mix of lithium, strontium, aluminum, silicon, lead, vanadium, arsenic, bromine that are in very small trace amounts

So, we ARE mostly water, when you combine the oxygen and hydrogen to make H20. Our skin, organs, muscles, bones, and nerves basically give the water a place to hang out. Now, the interesting thing is that, aside from the hydrogen, the rest of the stuff all comes from stars. Some of those elements are cooked up inside stars like the Sun. Others come from stars that exploded as supernovae. Each of those kinds of stars spent a long time converting fuel to heat, and in their old age, they blew off clouds of material that included these elements.

The late astronomer Carl Sagan coined the phrase “We are star stuff” to explain how we came from the stars, albeit in a very long, long birth process. A bunch of stars had to live and die in order to make the “stuff” that is in our bodies, that makes up our planet, and even our Sun. It’s great stuff, this starstuff!