Pulsars: The strangest stars in the universe
What is a pulsar, anyway?
Think of pulsars (pulsating stars) as little lighthouses. (And when I say "little," I mean in comparison to say, our sun.) These small and incredibly dense stars produce beams of electromagnetic radiation from their magnetic poles which, as the star spins, reappear and disappear, just like the lights of a lighthouse. This means that pulsars are visible to us only when their beams are pointed in the direction of the Earth.In this lens, I'd like to share with you my rather quirky and long-lasting love for the universe's little lighthouses. If you want to know the extent of my passion for these pulsating stars, just think of a little girl curled up under the covers at age 11 reading, not Nancy Drew or Goosebumps, but her precious astronomy book The Universe and Beyond!Perhaps by the end of this lens, you'll have become a member of the pulsar star fan club as well!Photo courtesy of NASA Goddard Photo and Video on Flickr
Fun Facts about Pulsars
There are more than 1800 known Pulsars in our galaxy.Pulsars slow down over time until they finally burn out.They can rotate at a speed of over 700 times per second.Pulsars are the collapsed cores of giant stars.Pulsars are so dense that if you took a spoonful of pulsar in hand, it would weigh a billion tons.Pulsars were first discovered in 1967 by graduate student Jocelyn Bell Burnell.
A Real Live Pulsar! - Doesn't it sound sort of sound like an African drum beat?
This pulsar is called the Vela pulsar. It lies in the centre of the Vela Supernova remnant, which basically means it is the core of the Vela star that exploded millions of years ago. It spins at the incredible speed of 11 times per second!
Don't be scared off by the complicated scientific name!
Sometimes, a pulsar finds itself in the company of another star. This is called a "binary system." Since the pulsar's gravitational field is usually much stronger than that of its fellow star, it pulls material away from its weaker companion and funnels this new found energy into its poles.
Since the material becomes so hot, the pulsar begins to produce X-rays, which can be seen from Earth as hot spots. These pulsars are called "accretion-powered pulsars" because they steal (or "accrue") energy from the stars around them. Pretty cool, huh!
Photo courtesy of Sarai Fotography on Flickr
What is the difference between a pulsar and a neutron star?
There actually isn't much of a difference! A pulsar is simply rotating a neutron star. The rotation of the pulsating star creates massive electric fields on its surface, which surge out of its two magnetic poles. Since a pulsar's rotational axis and magnetic field axis are never aligned, the beams of energy coming from the magnetic axis sweep around the collapsed star, creating the aforementioned lighthouse effect. Just as a ship on the sea can only see the lights coming from a lighthouse when the beams are facing the ship, we on Earth can only see a pulsar when its beams of magnetic energy sweep in our direction.
Pulsars and neutrons are both:
- collapsed cores of stars that underwent a supernova explosion- extremely dense (1.4 times the mass of our sun) and not very large (only about 20 km in diameter)
- formed of protons and electrons which combined to create neutrons (hence the name "neutron star")
Photo courtesy of NASA on Flickr
Book Review by Heather Broster: - The Universe and Beyond by Terence Dickenson
My personal review of the science book that gave me my passion for astronomy!
The Universe and Beyond was the first scientific book my father bought for me when I was a little girl. At the age of ten, I was already starting to show an interest in the mechanisms that influence our universe. Since my dad, like so many dads out there, didn't have all the answers to my never ending list of questions, he bought me this book so that I could do the research on my own.This Universe and Beyond, though written for adults, is easily accessible even to children, for its pages of bright and colourful pictures taken from telescopes and satellites, and relatively simple explanations. In this book, Dickenson takes you on an intergalactic journey, from our sun and the solar system, to the farthest outreaching areas of our universe and beyond. He discusses a sea of topics, such as black holes, quasars, nebulae, and of course, my favourite, the pulsar, and he does so with such a passion that you cannot help but become completely absorbed.I recommend this book to anyone just coming to grips with astronomy and outer space, whether they be a child or an adult. As it was written in 1998, some of the information will be out of date (i.e. the classification of Pluto as a planet), but this does not stop it from being a fascinating read.
Pulsars and Neutron Stars - Learn all about the cosmic magic behind these two types of stars
Another short video about Pulsars and Neutron Stars produced by the Chandra X-ray Centre of Massachusetts.
A Neutron Joke, just to lighten the atmosphere!A neutron walked into a bar and asked, "How much for a drink?"The bartender replied, "For you, no charge."
A "Diamond Planet" that orbits a pulsar?!
Apparently so, according to astronomers!
Imagine this. A planet, five times the diameter of the Earth, made purely of diamond!
(I can see girls turning their heads in interest all over the net!)
4000 light years away, in our home galaxy, lies a pulsar that keep as its companion this "galactic gem," a planet made up mostly of compressed carbon atoms - the perfect recipe for a pure diamond.
It apparently glows hot and white, making it easy to observe from a telescope.Visit Stuff.co.nz to find out the largest diamond known to mankind: Astronomers discover 'diamond planet'
The Pulsar Poll
Did you know what a pulsar was before reading this lens?
What is a pulsar wind nebula?
A pulsar wind nebula is a nebula powered by the pulsar wind of a pulsar. Usually, these nebulae are found in the shells of supernova remnants, but they can be found around a pulsar even when all the remnants have all disappeared. The winds slow down as they enter the pulsar, and speed up and they swirl around it.
The perfect example of a pulsar wind nebula is the Crab Nebula, located in the constellation of Taurus. The Crab nebula supernova was first observed in 1054 by Chinese and Arab scientists, as a bright "guest star" in the daytime sky, and was later rediscovered by John Bevis in 1731. The Crab pulsar, which sits in the middle of the nebula, is one of the most powerful pulsars observable in the night sky, with a rotational speed of 30 times per second.Read more about the Crab Nebula here: Crab Nebula
Great Books about Pulsars - Deepen your knowledge about these cosmic beacons in our night sky!
Links to Pulsar Star Websites - If you are looking for a deeper scientific explanation
- Pulsars - The University of California Observatories
This website will give you all of the scientific juice behind pulsar stars. I'm no Einstein, so I'll leave the explaining to them!
- The Nasa Goddard Space Flight Center
Who better to turn to than NASA if you want a good explanation about pulsars and how they work? Here, you'll find a very simple and concise description of pulsars that even the least scientific of us should be able to understand!
- SolStation - Pulsars
Another scientific site with "starloads" of information about pulsar stars!
- An Introduction to Pulsars
This website is really nice for us non-science folk. It describes pulsars in a simple and approachable manner that even your kids could understand!
- Pulsars Galore! Astronomy Blog
Interviews with pulsar experts and the scientist who discovered pulsars back in 1967, Jocelyn Bell.
If you're an average Joe like me, let me know what you thought of my article! If you're a super intelligent astronomer, let me know if all my information is correct! (Please and thank you!)