Voyager 2 at the edge of the heliosphere: Solar system shows clear edge


Voyager 2 at the edge of the heliosphere

The spacecraft Voyager 2 has determined that our solar system has an exactly definable limit. Nasa tempts you to poetry.

The Voyager 2 of NASA.

Illustrative illustration of the Voyager 2 probe Photo: Nasa

The sun's heliosphere is like a ship sailing through interstellar space. Write the NASA. As if the universe was a thundering ocean, as if the people were the on-board mice in the pantry of a wavering bark. The heliosphere is the space around our parent star that is still shaped by it, the echo of its radiation.

The space agency Voyager 2, which has already reached the border of our solar system last year and now slides 18.27 billion kilometers from Earth through space, gives the US space agency an opportunity to examine things above. The space between the stars.

The probe does its job, as does its sister probe Voyager 1. They measure and measure. Magnetic fields, electromagnetic radiation, plasma of hydrogen and helium nuclei; and they send and send to us.

Meanwhile, the Voyger 2 signals need almost 17 hours, although traveling at the speed of light. The Voyager 1 even over 20 hours. This is only possible because there is a battery on board with gradually decaying 4.5 kilograms of plutonium 238, which comes from a weapons factory. Now scientists have comprehensively evaluated the data from the past year and done what humans do: defining boundaries.

Pups in the bath water

Relatively abruptly, the composition of the plasma changes abruptly for cosmic conditions, and the radiation emitted by the sun weakens. Instead, remnants of final explosions take on long-extinguished stars or even the big bang itself.

For cosmic conditions relatively abruptly change the composition of the plasma

The stuff between the stars is denser and colder than our heliosphere, NASA has figured out, which makes the metaphor seem a bit slanted. Physically more precise would be: The heliosphere of the sun is like a pups rising through cold bath water.

But what does "denser" mean? The space outside is almost empty. Dicht means here a maximum of a few thousand atoms per cubic centimeter of space, which is only slightly more than nothing. Moreover, the magnetic field permeating the space inside and outside the supposed boundary between the realm of the sun and the realm of space remains the same. That is a mystery, writes NASA. Instead of calling out a border, she could have found more consoling metaphors: The heliosphere of the sun and the interstellar space connect delicate ties out of nothing.

. [TagsToTranslate] Nasa


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