BRAIN DUMP

Were there more volcanoes in prehistoric times?

Andrew Warren

■ The number of volcanic eruptions has certainly been higher during periods of Earth’s prehistoric past than now. Around 200 million years ago, for example, scientists think that the break-up of the supercontinent of Pangaea triggered 600,000 years of intense volcanic activity that led to mass extinctions. TL

What happened to the crew who dropped atomic bombs on Japan in WWII?

Peng Lan

■ In August 1945 a US air crew dropped an atomic bomb on Hiroshima, instantly killing an estimated 80,000 people. Days later, another crew dropped a bomb on Nagasaki, immediately killing around 40,000 people. Both crews survived, and though they spoke of the devastation it caused, most said it saved lives in the long run by putting an end to the war. JT

What if an astronaut floated away from the ISS?

Isobel Adams

■ This is very unlikely to happen as all spacewalking astronauts are tethered to the ISS with a braided