# How many neutrons are there in a teaspoonful of a neutron star and if stacked end on end, how far would these neutrons reach? [closed]

I am not a physicist nor a student of physics. I am just an old man that wonders. As such, I probably do not belong in this society. I've had a long interest in neutron stars. This interest began when a PBS scientist (physicist?) commented on a program (probably NOVA) that "a neutron star would be cool to the touch (about 80 degrees F), and a teaspoonful would have about the same mass as Mt. Everest". (I'm so sorry that I don't remember her name but the thought excited me.) Thank God (oops) that two neutron stars decided(?) to collide in my lifetime when it was possible that this collision was detectible. This collision (and its detection) created a new widespread interest in neutron stars. I'm sure that the data from this collision will be analyzed (and argued) for many years (long after I'm gone). And thank God (oops again) that the gravitational waves decided (ok, happened is a better word, but decided is sexier) to get here before the light did. That gave us enough time to locate it, film it, and analyze it. Ok, my ignorance is showing here and maybe this would have happened anyway. But I think it really convenient for us to get the gravitational waves first. Really? Earth size globs of gold and platinum. (Hitch up your wagons boys).

## closed as off-topic by John Rennie, Rob Jeffries, stafusa, M. Enns, Jon CusterNov 1 '17 at 19:38

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• direct quote from wikipedia "A neutron star is so dense that one teaspoon (5 milliliters) of its material would have a mass over 5.5×1012 kg (that is 1100 tonnes per 1 nanolitre), about 900 times the mass of the Great Pyramid of Giza. ". – JMLCarter Nov 1 '17 at 18:15
• Hi and welcome to the Physics SE! Please note that you are expected to have thoroughly searched for an answer before asking your question. You can consider checking the advice on writing good questions. – stafusa Nov 1 '17 at 18:43

So 5.5 Pg of neutrons is $3.3 \times 10^{39}$ neutrons. Their diameter is 1.75 fm--so end-to-end: