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Ron Dippold
San Diego, California, US
If you approached a neutron star, you would be instantly crushed by gravity and fried by X-rays, while your very atoms would be torn apart by magnetic fields and gravity – making you a splattered stain on the surface.
But let’s wave our magic wand and let you survive. This surface is a thin, neutron-rich lattice “crust” a couple of hundred metres thick over neutron fluid sloshing around inside. There would be intense gravitational lensing. A neutron star is halfway to becoming a black hole, so light would be visibly bent. Unlike Earth, where you can see things drop below the horizon (proving it is a sphere), you could see up to about 80 per cent of a neutron star while standing still, since the light is bent so much!
Time runs about 20 to 30 per cent slower here due to the extreme gravity, so things seem to orbit faster and are blueshifted. The airless sky would be full of auroras from the intense magnetic fields, especially if the neutron star were a pulsar. If you dropped anything, it would reach the surface in less than a microsecond and cause a nuclear explosion with intense gamma and X-rays.
If it were orbiting a star like our sun, the light from the neutron star would be bluer and brighter due to gravitational lensing and time dilation. If it were new, it could be 1 million °C and there might be some blue glow from this heat, but you would probably only be able to see that in X-ray wavelengths.
Once it cooled down, the neutron star would be dark and only lit by its companion star. You might still see some bright spikes at the poles from the magnetic fields. From Earth, the neutron star would be invisible to our eyes, given it would be only about 12 kilometres across, even though it would be 40 per cent more massive than our sun.
If I had a magic wand of invulnerability, I would definitely want to visit a neutron star. But once would probably be enough.
Eric Kvaalen
Les Essarts-le-Roi, France
You wouldn’t be able to look at a nearby neutron star with the naked eye, as it would be glowing with a bluish light so strong it would blind you.
But if you had enough pairs of sunglasses on, you would see just blue light. You wouldn’t, however, be able to discern that the surface is very smooth and composed not of neutrons, but of atoms of carbon and oxygen. There would be a very thin plasma of carbon and oxygen above the surface, but you wouldn’t see that either.
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