Four and a half decades after launch and more than 14 billion miles from Earth, Voyager 1 still making new discoveries. The spacecraft has picked up signals from interstellar space itself, the faint “hum” of plasma that scientists “hum” against the soft rain.
Plasma was part of the Voyager 1 mission from the start – the spacecraft detected lightning strikes Jupiter’s atmosphere and studying how the solar wind shrinks in the outer solar system.
And since 2012, scientists have focused spacecraft instruments on completely unexplored parts of space. It was then Voyager 1 goes through the heliopausewhere the solar wind – the constant stream of charged particles flowing from the sun – is no longer strong enough to hold the interstellar medium that surrounds our tiny environment. Since 2012, when Voyager 1 moved further from the sun, the spacecraft has been measuring the surrounding plasma.
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This part of the interstellar medium was mostly silent. “It’s very weak and monotonous because it is within a narrow frequency bandwidth,” said Stella Koch Ocker, a PhD student at Cornell University who led the new research. word in a statement. “We found a faint, persistent hum of interstellar gas.”
But every few years Solar wind push. Voyager 1 considers this event to be a shock wave. “If there is a solar burst, it is like finding a bolt of lightning in a storm,” said senior author James Cordes, an astronomer at Cornell, in the same statement. “Then another splash.”
For a while, scientists thought these shocks were the only way Voyager 1 could measure plasma density.
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But now that scientists have heard of these unexpected rumors, they can track the interstellar medium between shocks, which could help them understand more about this largely undiscovered expanse of space. Ocker believes there is far more low-level activity in the interstellar medium than scientists previously thought.
“We now know that we don’t need random solar-related events to measure interstellar plasma,” Cornell astronomer Shami Chatterjee said in the same statement. “Regardless of what the sun is doing, Voyager is sending the details back. The vehicle says, ‘This is the density I’m going through. And here it is now. And here it is now. And here it is now. ‘far enough and will continue to do so. “
Voyager 1 and its twin, Voyager 2, will become Sailing to the stars since time immemorial. But for scientists here on Earth, the spaceship’s days are numbered. At some point this decade, the spacecraft’s plutonium resources will dry up forever.
Meanwhile, scientists enjoy every data that flows back. “It’s a technical flair for science that’s always being passed on,” says Ocker.
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