It took a few tries, but I got Wolfram Alpha to compute its velocity compared to the speed of light[1].<p>I started with:<p><pre><code> sqrt(1-((1/(1+120 PeV / (neutrino mass * c^2)))^2))
</code></pre>
but it simply said "data not available". So I changed:<p><pre><code> 120 PeV to 120e15 * 1.602176634e-19 kg m^2 s^-2
neutrino mass to 1.25e-37kg
speed of light to 299792458 m/s
</code></pre>
and finally it gave a numeric result:<p><pre><code> 0.999999999999999999999999999999999999829277971
</code></pre>
(that's 36 nines in a row). Pasting it in Google says the value is "1", which is… not far off.<p>If you want details about the way this is calculated, I dug up the formula from an article I'd written about particle velocities in the LHC, back in 2008[2]. For comparison, their 7 TeV protons were going at 0.999999991 × c.<p>[1] <a href="https://www.wolframalpha.com/input?i=sqrt%281-%28%281%2F%281%2B%28120e15*1.602176634e-19+kg+m%5E2+s%5E-2%29+%2F+%281.25e-37kg++*+%28299792458+m%2Fs%29%5E2%29%29%29%5E2%29%29" rel="nofollow">https://www.wolframalpha.com/input?i=sqrt%281-%28%281%2F%281...</a><p>[2] <a href="https://log.kv.io/post/2008/09/12/lhc-how-fast-do-these-protons-go" rel="nofollow">https://log.kv.io/post/2008/09/12/lhc-how-fast-do-these-prot...</a>