Make the sea salt speak

1 · Make the second flash visible

Beginner

Why is a neutron captured by chlorine easier to see than one captured by hydrogen?

Its capture releases far more energy Its capture comes a good deal later Its capture emits a second positron

2 · Watch for a distant star

A star of 27 solar masses, like the article's benchmark star, collapses 80 kiloparsecs away.

Intermediate

Does TRIDENT detect it with 5-sigma significance?

Yes, even with the first flash alone Yes, but only with the neutron No, it is too far in every case

3 · Split the neutrons

Chlorine-35 makes up about 0.25% of the nuclei in seawater, hydrogen about 66%. Chlorine captures a slow neutron about 130 times more readily. Count only these two nuclei.

Expert

Out of three captured neutrons, roughly how many are captured by chlorine?

One Two All three

4 · Move it under the ice

Expert

Would the same trick work as it is in IceCube's ice?

Yes, ice is still water Yes, and better, as it is colder No, ice has no chlorine

Neutron captured

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