Probably because a magnetar could sterilize everything in a radius of dozens of light years if it has hiccup.

All ordinary "room temperature and pressure" matter that we're used to -- that we're made of -- can be thought of as bathtub foam compared to a neutron star stuff that is more like a tungsten brick in that analogy.

Well, not quite, because that analogy misses ten orders of magnitude of density difference. That just hurts my brain.

Magnetars are a whole other level of eldritch madness. The energy density of their magnetic fields is ten thousand times the density of lead.

Let that sink in for a minute.

The vacuum around a magnetar contains so much energy in the magnetic field alone that thanks to the E=mc² conversion ratio between energy and mass it has a "mass density" that is the direct equivalent to every single atomic bomb on the planet blowing up all at once and the released energy of all of that getting packed into a cubic centimeter.

I need a hug.

aren't pulsars and magnetars very small when talking about stars and planets? Google's AI says about 20km in diameter but would need to double check that. On the other hand, IIRC the energy output of a pulsar compared to its physical size is pretty scary. You wouldn't want one in your neighborhood.

Yes. Here are fact checks for those who don't trust the easy AI answer:

https://www.britannica.com/science/pulsar

https://en.m.wikipedia.org/wiki/Magnetar#Description

They are both forms of neutron stars, which average around 20km but are the densest objects known to man. Fun fact, one sugar cube of their material would weigh about as much as a mountain (https://imagine.gsfc.nasa.gov/science/objects/neutron_stars1...).

> but are the densest objects known to man

Only in the sense that black holes don't have finite densities.

idk but theres a whole subreddit dedicated to it https://www.reddit.com/r/megalophobia/