|Ryukyu Astronomy Club Newsletter
|Volume 1, Issue 4||June 2002|
Next Club Meeting - June 8th
Things to See This Month
To get a safe view will require either a safe filter or a method to project the image onto a light surface. Solar filters suitable for normal viewing of the Sun are safe for viewing eclipses as well - so if you have a solar filter for your telescope or binoculars this would be an excellent time to use it. It is also safe to view an eclipse through #14 welder's glass, but since welder's glass is not reliably marked, this can be extremely dangerous and lead to permanent eye damage.
Projection methods are very safe and allow a group of people to observe simultaneously. A simple and effective projection viewer can be made with two small pieces of white poster board, say 9 inch square. Cut a small opening about 1" square in the center of one of the pieces. Tape a piece of aluminum foil to cover the opening. Then use a straight pin or needle to poke a tiny hole in the foil. (Alternately you can poke the pin hole directly in an uncut piece of poster board, but the edges of the hole will be ragged and the image will suffer.) During the eclipse, let the light pass through the pin hole and project onto the second piece of poster board. Move the poster board closer together and further apart to adjust the size and sharpness of the image.
Now let's just hope for a clear morning on the 11th!
The three main building-blocks of atoms are electrons, protons and neutrons. Electrons are negatively charged and protons are positively charged. Like magnets, two electrons will repel each other (as will two protons) unless they are part of an atom. Atoms with electrons and protons can only get so close together before the repulsion force prevents them from getting any closer. A sphere of pure electrons cannot exist, nor can a sphere of pure protons.
But, neutrons have no charge, so a sphere of pure neutrons can become incredibly dense. The remnant of a supernova - a neutron star - is such a sphere. Astronomers are still forming theories on the deep core of neutron stars, but basically it consists of particles (mostly likely neutrons or more exotic forms of matter) that are closer together than is possible in normal matter. The shell of a neutron star is almost certainly about 200 meters of solid iron.
Beyond their composition, neutron stars are odd in other ways. Despite their high density and large mass, they spin at an incredible rate - sometimes more than 100 revolutions per second. And a mechanism that is not yet fully understood turns that rotation into pulses of X-rays and other radio waves. In fact, in the 1960s astronomers detected fast, blinking radio wave sources that they named pulsars due to the detection of these pulses. They soon decided that the only likely source for these pulsars were neutron stars. And the density of their matter is incredible - imagine a spoonful of matter that weighs more than a billion tons!
In the year 1054, Chinese astronomers noted a brilliant star that wasn't there before - a supernova in the constellation we now call Taurus. It was so bright they recorded it was visible for 23 days - in full daylight! Today it is known as the Crab Nebula - object 1 from Messier's catalog. The cloud of energized gas that we can see in telescopes harbors a neutron star, visible only by the X-rays it continually emits. The X-rays indicate it rotates at 30 times per second. Consider taking a ball the size of a city, with the mass of our Sun, and spinning it at 30 times per second - conditions that are truly unbelievable. Viewing M1 will be the closest most of us will get to seeing a neutron star.
Visit http://imagine.gsfc.nasa.gov/docs/science/know_l1/pulsars.html to learn a little more about neutron stars in largely non-technical terms. Visit http://csep10.phys.utk.edu/astr162/lect/neutron/neutron.html for a more technical discussion.
Other Club Business
Ryukyu Astronomy Club
Contact the Webmaster: