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A pulsar is a highly magnetrized rotating neutron star. They appear to pulse because they have jets of particles moving almost at the speed of light coming from their magnetic poles. These jets produce powerful beams of light. The magnetic pole is slightly misaligned from the rotational axis line, like the magnetic pole on Earth is not in line with our "true north". Picture holding a flashlight in your hand and rotating your hand around. The beam from the flashlight will appear to pulse as it heads towards you and then it stops as it swings away. We observe the beams of light from pulsars only when they are pointing towards Earth and then they appear to go off as the pulsar's magnetic pole is facing away from Earth. This is called the lighthouse effect. The period of pulses range from 1.4 milliseconds to 8.5 seconds.
Shown below is an artist's concept of a pulsar surrounded by material blown away by the supernova explosion.
Image from http://www.nasaimages.org
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I did an earlier post of the Life Cycle of a Star. A neutron star is one possible final phase of a star. It is quite a fascinating object that I thought it deserves its own post.
- Neutron stars are unbelievably, incredibly dense. They have a mass about 1.5 times that of our Sun but with a diameter of about 12.5 miles!
- The density of the star has caused the protons and electrons to combine into neutrons, thus giving the stars their name. One teaspoon of its material would weigh over 5 million tons on Earth.
- The denseness also causes an amazing amount of gravity. The escape velocity from the surface of a neutron stay is about one third the speed of light.
- The massive gravity of the star warps light. If we could look at a neutron star, we would be able to see more than half of the star at a time as shown by the image.
- Neutron stars rotate very quickly, some up to several times per second.
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The sizes of some of the objects in space are huge. So huge it is difficult to us to comprehend exactly how large they are. Here are some images that may help show the difference in sizes.
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This is an AMAZING video that starts on planet Earth and zooms out to show the entire universe and then back again. Nothing demonstrates better how insignificant we are in the scope of things.
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The West Mata Volcano sits in the Pacific Ocean between Fiji, Tonga, and Samoa almost 4,000 feet below the ocean's surface. The eruption was first spotted in May as it spewed out boninite lavas that are among the hottest recorded in modern times. The water from the volcano was as acidic as battery acid. This video was obtained by using a remotely operated submarine. The pressure of the sea water at that depth was able to suppress the explosive quality of the eruption and allowed the submarine to get quite close.
Boninite lava was previously only found in extinct volcanoes in samples that were at least a million years old. This eruption is the first time scientists could watch the material being created and witness the molten lava flowing on the ocean floor before it was cooled and hardened by the cold water.
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NASA/BioServe, Univ. of Colo.
Two kinds of caterpillar larvae arrived at the International Space Station last month - Monarch and Painted Ladies. After completing their pupa stages, the first butterflies emerged as the newest kind of residents on the space station. This is the first time that the colorful insects went through all stages of their development (larva, pupa, butterfly) while in orbit.
On Earth, a newly emerged butterfly's wings take about 3 - 5 minutes to dry. In space it took closer to 15 minutes. Their lifespan on the space station is expected to be about half of what it would be on Earth. One thing is the same: you can see lots of larvae poop floating around in the enclosure.
NASA attempted this same experiment a year ago, but the caterpillars never developed into butterflies due to a bad batch of food.
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National Geograhic has mapped close to 200 space explorations missions in the picture below. Most have been to our closest neighbors, Venus and Mars and our Moon.
Click image to view full size.
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A new planet was discovered that orbits its star in the opposite direction of the star's rotation. Normally, as a star is spinning it will cause the nearby debris to start circling the star in the same direction and the debris can form planets. It is likely that this planet was orbiting the star in the expected direction, but a close call with another large body could have been the cause of its direction change. This planet, named WASP-17b, has other interesting properties. It orbits very close to its star, less than one-seventh the distance that is between our Sun and Mercery. It is also about twice the size of Jupiter, but only half its density (similar to a packing peanut).
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The International Space Station (ISS) is a research laboratory being built by a number of space agencies. Construction began in 1998 and is supposed to continue into 2011. It is the largest artificial satellite in orbit around Earth and can be see with the naked eye. ISS is in a very low orbit around Earth, only about 242 miles overhead, and circles the Earth 15 times a day. The cost of building this facility is expected to top out around $100 billion dollars, with the US picking up close to a third of that. Unfortunately, NASA only has funding for the project through 2015. If it doesn't find the money to continue, it plans to "de-orbit" the space station in the early part of 2016. Deorbit does not mean taking it apart and bringing it back down to Earth in pieces. It means changing the orbit so that it crashes into the Pacific Ocean. They estimate 80% of it would burn up in the atmosphere and the remaining 20% of the debris would fall into the ocean in an area the size of Alaska.
They do allow tourists to come visit the station at a bargain price of $25 million each. That seems to be the way to go since they make the astronauts on the station work 55 hours a week.
Photo from nasaimages.org