Most light pollution isn’t coming from streetlights

Light pollution is the arch nemesis of astronomy, spoiling both the enjoyment of the night sky and the professional study of our universe. For years we’ve assumed that streetlights are the main culprit behind light pollution, but a recent study has shown that streetlights contribute no more than 20% of all the pollution, and if we want to solve this vexing astronomical problem, we have to think harder.

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Astronomers are ready and waiting to detect the neutrino blast from a nearby supernova explosion like Betelgeuse

When giant stars die in impressive supernova blasts, about 99% of the energy released goes into producing a flood of neutrinos. These tiny, ghostly particles slip through tons of matter like it’s not even there. But a new generation of detectors will be able to catch them, telling us of the inner machinations of the deaths of stars.

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There’s a new record for the shortest time measurement: how long it takes light to cross a hydrogen molecule

HD+ molecular ions (yellow and red pairs of dots: proton and deuteron) suspended in an ultra-high vacuum between atomic ions (blue dots). Credit: HHU / Alighanbari, Hansen, Schiller

To measure small differences in time, you need a really tiny clock, and researchers in Germany have discovered the smallest known clock: a single hydrogen molecule. Using the travel of light across the length of that molecule, those scientists have measured the smallest interval of time ever: 247 zeptoseconds. Don’t know what a “zepto” is? Read on…

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The galaxy with 99.99% dark matter isn’t so mysterious any more

The dwarf galaxy known as Dragonfly 44 caused a stir recently: apparently it had way, way more dark matter than any other galaxy. Since this couldn’t be explained by our models of galaxy formation, it seemed like an oddball. But a new analysis reveals that Dragonfly 44 has much less dark matter than previously thought. In short: it’s totally normal.

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