Neutron stars don’t get much attention these days. They’re not as notorious as black holes, despite warping space and time almost as intensely. Still, the media usually shy away from runners-up and wannabes. Which is why none of us can name the second team that scaled Mount Everest. But when it comes to bizarre celestial objects, it’s a real shame. It’s like ignoring a talking gorilla sitting next to you at the movies just because a flying saucer is in the parking lot.
This story really started before dawn on July 4, 1054, when a new dazzling star abruptly appeared near the left horn of Taurus the Bull, very close to where the Sun is located the next few weeks. It was seen in broad daylight for months. These mornings just before dawn, good backyard telescopes reveal this as the twisted remnant of an exploded star 6,500 light-years away, whose tendrils still rush outward at a thousand miles a second, visibly altering the nebula every few years.
If it›s weirdness you want, you can’t do much better than this region that’s now behind the Sun. Its bizarre glow is not starlight, nor reflected light, nor excited gas. The Crab Nebula’s glow is an exotic phenomenon called synchrotron radiation, produced when electrons are forced to change direction by super-powerful magnetic fields. But don›t picture the kind of magnetism that wobbles a compass needle. The field near the Crab is a trillion times stronger than Earth›s and would rip that compass right out of your hand. It blasts electrons into violent spiraling geysers that produce bits of eerie blue light like yelps of protest.
But this strange lavender glow is just the cloak that surrounds the inner sanctum of strangeness. Because most astronomers focus on the object at the heart of the nebula, the thing that creates the unearthly magnetic field and strange blue radiation. The Crab Pulsar.
A pulsar is a tiny solid star whose magnetic poles sweep past our line of sight with each rotation. Like a lighthouse, it delivers a quick burst of energy with every turn. This is what remains of the original giant star’s core. When the star went ka-plooie and exploded outward, this tiny remnant, its nucleus, went the other way and collapsed inward. As it spins 30 times a second, its light looks visually steady because nobody can differentiate more than 20 flashes per second, the human flicker-fusion threshold.
Its intense magnetic field acts as a drag, a brake and slows the wildly spinning star so that this pulsar will whirl «just» 17 times a second by the year 4000.
I wish we were around a thousand years ago to watch that unfortunate sun blow itself to Kingdom Come. As the star’s core dramatically deflated like a punctured balloon, the material of a half million planet Earths almost instantly packed itself into a ball smaller than Brooklyn.
Ever-strengthening gravity imploded its contents. Its atoms were all fused into a compressed ball of neutrons. Dense is a pathetic understatement. The star›s density would be duplicated if 640 cruise ships could be crushed down to the size of a sugar cube. Except, here there isn›t merely a speck of the stuff, but a sphere 12 miles across.
Interestingly enough, this is the same density of every atomic nucleus in your body. We usually think of stars as gassy and unsupportive. The sun›s vaporous visible photosphere is less dense than water. But unimaginable gravity has forced the Crab pulsar’s broken atom fragments into a kind of glasslike structure with a hundred thousand trillion times the hardness of steel. It doesn›t need to be insured. You couldn’t damage it, or even scratch it, not even with a hydrogen bomb.
A half mile beneath this impenetrable crust, the star turns liquidy yet gets even denser, but nonetheless boasts a super-slipperiness that lets the interior spin faster than its surface. And at the center only a few miles down, we find a mystery. It’s not being cute or exhibiting modesty to shrug our shoulders at this point.
Because here, our present science comes to an end.
Few sights are as mind-bending as a meteor storm. That’s when at least one bright shooting star streaks across the sky every single minute. It’s unlikely, but definitely possible that we’ll see such a spectacle on Monday night, May 30. It will be moonless, providing perfect conditions. So if it’s clear or mostly clear that night, take a look overhead anytime in the hour that begins at midnight. You never know! We last saw such a spectacle on November 19, 2001 and the next is not likely until 2099.