Record-breaking neutrino is most energetic ever detected (opens in new tab)

The kilogram is the base unit of mass in the International System of Units (SI): https://en.wikipedia.org/wiki/SI_base_unit

Time is in seconds, length in meters, temperature in kelvin, etc. A unit of energy like a joule is then defined using these base units, so 1 joule is 1⋅kg⋅m^2⋅s^-2.

In particle physics you just use GeV (with varying powers) for most parameters :)

>Every one of us has tens of trillions of neutrinos passing through us every second, but fewer than five of them actually interact with the matter in our bodies in our entire lifetimes.”

Oh, but those five...

These rare interactions with matter are also a cause of concern in voting machines, right? Or at least it was a concern at one point. A random bit being flipped or something.

Interesting "fact" - The total amount of lead in the universe is a somewhat less than a cubic light year.

> So you're saying my iPhone built-in calculator app is going to have problems....?

Your Android phone's built-in calculator app, however, will not. :^)

https://dl.acm.org/doi/pdf/10.1145/3385412.3386037

Are you implying that people who use the metric system have an intuitive sense of what 120 PeV means?

No, it is called giving context.

> typical body builder expends about 1 horse power while performing

Close, but ackshually...

Bodybuilders just oil up and pose in beauty pageants.

1 horsepower is basically one 250-pound bench press in one second. (550 foot pounds of work; the aforementioned bench press assumes a 2.2-foot stroke length.)

Most bodybuilders and serious weight lifters can do that, but they can't keep it up for long.

Fun fact, a typical horse exerts about 1 horse power of usable work while performing. That's so weird, I'm sure almost no one would've been able to guess that - but it's true.

(To be clear, that's sustained effort over time, not just momentary. Athletically trained humans can do about 1 HP of peak momentary effort, and around 0.3 HP if sustained over time.)

It must have been a very short amount of time. 2 HP is 1,500 watts, probably more light than all lightbulbs in my house combined.

So, 2,000 milliSchwarzeneggers if we use SI units?

Can we harvest that energy?

Particle on steroids.

A ping pong ball would be roughly 2 trillion trillion atoms, for reference

The mean free path of neutrinos through lead is around one light-year. So, taking the thickness of the body to be 1/2 a meter, you would expect the probability of any individual neutrino to interact with the body to be ~5 x 10^-17. So you'd ballpark have around a 20--40% chance that a single neutrino interacts with your body. It would probably cause a localized radiation burn. Detectable, but probably not lethal unless you got really unlucky with where it hit you.

> big boom

The probability of interaction of neutrinos with matter increases with the energy. I've asked o1 to estimate the mean free path of a 120 PeV neutrino in water and it came up with 1000km. So let's say, conservatively, that 10^-7 of the total energy gets deposited in your body when the beam goes through. The mass equivalent of a ping pong ball is about 2.5x10^14 J, which gives us 2.5x10^7 J total, or about 6kg TNT equivalent. This is only an order-of-magnitude estimate, but it would definitely not be healthy.

Total energy of impact would be 120 PeV x 10^16 = 120 x 10^31 eV = ~60 kilotons TNT, or 4 Hiroshimas.

So BIG boom.

Since the velocity is so close to the speed of light, you can think of this like the energy released by annihilating a ping pong ball made of antimatter.

Edit: Commenter asked what would happen if they "hit", so I'm assuming a hypothetical 100% collision. But yes to stop 1/e of a neutrino beam with normal matter, you'd need a light year of lead.

Sounds like a great topic for an xkcd video

Isn't Ant-Man logic that he still has the same mass when he shrinks and, as such, can generate the same force?

Unless you get thrown back by ping pong balls normally, I think you'd be fine.

I would expect it to be more likely to punch through skin than to actually propel you.

But also neutrinos don't typically collide with things very easily, they're more likely to pass through you without you ever knowing.

Most likely a heavier nucleus than a proton too

It's worth noting that we received the neutrinos from Supernova 1987a before the photons. We think that's because the photons have a difficult time escaping the ejecta cloud, while neutrinos stream away freely, but who knows ...

It’s very close to c though, close enough that it beats sending a signal around the Earth.

The drawback is the impractical size and cost of a receiver.