Subscribe to TimeLeftPulsar
I could not help myself … that 7 times per second spin rate and 20 km diameter fascinated me.
I wondered what the centrifugal force on the surface of that Pulsar is?
So I did a few simple computations (yeah; they used to be simple for me, but I had to look up the equations, as my mind has lost them).
Anyway, an object 20 km in diameter, spinning at 7 RPS, has a circumference of Pi D = 3.1416 x 20 = 62.9 km., so the surface is moving at 440.3 km/sec.
Fast, but a long way from the speed of light…. but perhaps enough to produce some marginal relativistic phenomena ??
I am guessing some time contraction/slowing, and that would mean effects on what I’ve just calculated … if so, then time passes at a different rate as a function of the radial distance from the center.
But what’s the surface acceleration induced by that rate of rotation?
The equation I found said: accel. = tangential velocity squared divided by the radius, or: 440.3 squared divided by the 10 km radius., or 19,386 m/sec sq.
Now one g on Earth is 9.8 m/sec sq. so the centrifugal acceleration on surface of that pulsar is 19,386/9.8 = 1,978 g’s
I don’t know what the gravitational acceleration is on the surface of the pulsar … that’s a separate computation that depends upon its density; and I don’t have any info on that.
But we know at least one thing about it … its surface gravity must exceed about 2,000 g’s … or it would have flown apart long ago.
Very strange things the Lord has placed in His universe!
Bill
PS: Hey, check my numbers; I’m quite capable of dropping a decimal point, or just using the wrong equation. BH
===========
On Sat, 1 May 2010 07:53 “Roy Moore rmoore63@juno.com writes:
Seven RPS? Would someone good with math tell me about what speed the outer surface of that star would be moving? Near the speed of light?
For sure the star would be larger than the earth and using 24,000 miles at the equator and spin the earth at seven rps; 168,000 fps. ninety percent of the speed of light?
Perhaps that is only the core that spins at that rate with an outer shell spinning at a slower rate? My mind is not yet fully awake.
Roy
————
On Sat, 1 May 2010 07:35:50 -0500 “Bob” bfizer@att.net writes:
Anyone with a keen eye can see that it’s Casper the Ghost….
Explanation: As far as pulsars go, PSR B1509-58 appears young. Light from the supernova explosion that gave birth to it would have first reached Earth some 1,700 years ago. The magnetized, 20 kilometer-diameter neutron star spins 7 times per second, a cosmic dynamo that powers a wind of charged particles. The energetic wind creates the surrounding nebula’s X-ray glow in this tantalizing image from the Chandra X-ray Observatory. Low energy X-rays are in red, medium energies in green, and high energies in blue. The pulsar itself is in the bright central region. Remarkably, the nebula’s tantalizing, complicated structure resembles a hand. PSR B1509-58 is about 17,000 light-years away in the southern constellation Circinus. At that distance the Chandra image spans 100 light-years.
May 2nd, 2010 at 4:38 pm
See http://www.nrao.edu/pr/2006/mspulsar/
“The scientists discovered the pulsar, named PSR J1748-2446ad, in a globular cluster of stars called Terzan 5, located some 28,000 light-years from Earth in the constellation Sagittarius. The newly-discovered pulsar is spinning 716 times per second, or at 716 Hertz (Hz), readily beating the previous record of 642 Hz from a pulsar discovered in 1982. For reference, the fastest speeds of common kitchen blenders are 250-500 Hz.”
–Edward L. (Ned) Wright, David Saxon Presidential Chair in Physics
Professor of Physics and Astronomy