back
12 comments
The article hardy makes any sense. You can't make a fusion of bottom quarks because they don't stick together. Reading the abstract of the paper, http://www.nature.com/nature/journal/v551/n7678/full/nature2... the reaction is

Lambda_b + Lambda_b -> Xi_bb + n

(up+down+bottom) + (up+down+bottom) -> (up+bottom+bottom) + (up+down+down)

This makes sense because each quark is inside a baryon with three quarks.

They say this is equivalent to the fusion of

D + T -> He + n

[proton+neutron] + [proton+neutron+neutron] -> [proton+proton+neutron+neutron] + neutron

[(up+up+down)+(up+down+down)] + [(up+up+down)+(up+down+down)+(up+down+down)] -> [(up+up+down)+(up+up+down)+(up+down+down)+(up+down+down)] + (up+down+down)

The analogy is very very very week. They are very different reactions.

The worse part is the total linkbait title. If you somehow magically can create a lot of Lambdas_b, in a very small time all of them will get transformed into protons, electrons and a lot of gamma rays. If you have enough you will have a nice explosion.

But if in the middle of the transformation they collide and produce some Xi_bb, the Xi_bb's will decay soon into protons, electrons and a lot of gamma rays. You don't get more energy because some of the Lambda_b get temporaly transformed into Xi_bb, the final energy is the same, so the risk is obviously zero.

For comparison, Deuterium is stable and Tritium is almost stable, so you can produce and accumulate them conveniently. And a bunch of Deuterium and Tritium will not cause spontaneously a nuclear explosion. But if you convince them to undergo fusion, you get a nice explosion. The final products are stable Helium and almost stable neutrons, so this reaction is enabled because Helium exist, so D+T->He+n is interesting.

I think we are nearing click bait here, which is becoming a more and more common on HN
How so? It's the original title, and it aptly described the article.

We are probably just becoming more sensitive and resistant to having our feelings manipulated constantly. Which I think is a good thing.

Edit:On second thought, I got further in the article and it's clear that the whole "we almost kept it secret" angle is a total stretch created by the author to make for a more exciting read. Yeah, this is click bait. Although, it's cool to know that you can theoretically smash two quarks together and get a boom.

Just because it's the same as the original title doesn't mean it's not click bait. It just means the original title is click bait too.

A non clickbait-y title would explain what the article was about instead of creating mystery so you would follow through.

If you email the mods hn@ycombinator.com , they sometimes change the title. It's better if you send an alternative, preferably the subtitle or the main sentence of the article.
the article was interesting to me but the title has that buzzfeed feeling to it.
1 picosecond is about the time it takes light to travel half the length of a single grain of salt. What a Joycean level of measurement.
The article talks about fusion chain reactions in hydrogen bombs, but the fusion in hydrogen bombs isn't an exponential sequence of chain reactions, it's due to very high temperatures caused by fission chain reactions in the primary. Hence the term "thermonuclear".
Despite the fact that a bottom quark fusion event emits 18 times the energy of traditional fusion (deuterium nuclei), the discoverers note that it's not possible to create a chain reaction of bottom quark fusions. So there are no military applications (or energy applications for that matter).
To put it in terms more relatable to ordinary life, the energy given off by one of these events is approximately 0.0000000000000061 watt-hours. That is about how much energy a typical LED light bulb uses in 2.5 picoseconds.

Without a chain reaction, it is hard to think of any way that this could be used to cause any noticeable effect at all anywhere outside of a particle accelerator facility.

OT: my God, the dictionary that Firefox 57 uses by default on MacOS sucks. Neither "relatable" nor "picosecond" are in it!

> a bottom quark fusion event emits 18 times the energy of traditional fusion

Small correction. The article says the MeV is 8x not 18x

Ah, I stand corrected.