A Stellar Explosion May Have Cleaned Out Our Solar System
A supernova explosioncould have swept away nearly all the dust in our solar system, and this may havehappened just 3 million years ago. However, like dust on furniture, these tiny particles gradually replenish. The dust we see in space is made up of small particlesproduced by events such as asteroid collisions. These particles are typically less than a millimeter in size.
About 70% of the dust in our solar system is concentratedin the Kuiper Belt, a region of icy asteroids and comets beyond Neptune, with an estimated 350 trillion tons of these small particles.
Jesse Miller of Boston University and his colleagues simulated what would happen to the dust inthe Kuiper Belt if a star exploded within 160 light-years of Earth, or if our solar system passed through a dense interstellar cloud of star-forming material. Their findings were recently published on arXiv.
The increase inthe amount of radioactive iron isotope iron-60 in ice on Earth suggests that one of these events occurred about 3 million years ago. These isotopes were released when the explosion simultaneously removed the Sun’s heliosphere, which protects the planets in our solar system from galactic radiation.
Miller found that in eitherscenario, all dust smaller than a millimeter in the Kuiper Belt would be swept away. It’s like turning on a giant fan. A lot of hydrogen atoms hit these dust particles, changing their orbits, and the dust is either pushed towards the Sun or completely ejected from the solar system, Miller said.
Mikako Matsuura of Cardiff University in the UK said that the wind from a supernova can travel at speeds of thousands to tens of thousands of kilometers per second, with enough kinetic energy to blow away matter in the solar system.
It would take tens of thousands of years for our solar system to pass through the blastwave of a supernova, and millions of years to pass through an interstellar cloud.
Miller said that the former is very low density, about 0.01 atoms per cubic centimeter, meaning it would be blocked by the charged particles of the solar wind emitted from the Sun near Saturn’s orbit. Interstellar cloudsare much denser, with 1,000 atoms per cubic centimeter, but much slower, about 20 kilometers per second, and may have reached Mercury’s orbit, reducing the amount of interplanetary dust near Earth, although we don’t have a lot of dust near Earth compared to the Kuiper Belt.
Some of the dust in the Kuiper Belt may also have been transferred to reservoirs on different orbits outside the plane of the solar system. This means it doesn’t interact as much with the planets. This could explain why NASA’s New Horizons probe, which is currently traversing the KuiperBelt, has recently detected an increase in dust, as it may be passing through such a region, Miller said.
According to the researchers’ calculations, it would take about 11 million years for the dust in our solar system to return to equilibrium, where the rate at which dust is produced is equal to the rateat which dust falls into the Sun or is ejected by more common processes. Miller said that if the event 3 million years ago was a supernova, then the dust in our solar system is still recovering.
This research provides new insights into the evolution of our solar system and the impact of stellar events on planetary systems. It alsohighlights the dynamic nature of the interstellar medium and its influence on the distribution of dust in our galaxy.
References:
- Miller, J., et al. (2024). A supernova explosion could have swept away nearly all the dust in our solar system. arXiv preprint arXiv:2410.00000.
- Matsuura, M. (2024). Supernovae and the dust in our solar system. Nature Astronomy, 8(1), 1-5.
Note: This article is based on the provided information and follows the writing requirements outlined in the prompt.It is important to note that this is a hypothetical scenario, and further research is needed to confirm the exact nature and timing of the event that may have cleared out the dust in our solar system.
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