- 2916 - ASTEROID - near miss? Many nearby stars will pass close to the Oort Cloud at the outskirts of our Solar System, but only one will move through it. In about 1.35 million years, Gliese 710 likely will gravitationally perturb millions of comets, sending a sizable number on a potential collision course with Earth.
--------------------------- 2916 - ASTEROID - near miss?
- Every 50,000 years or so, a nomadic star passes near our solar system. Most brush by without incident. But, every once in a while, one comes so close that it gains a prominent place in Earth’s night sky, as well as knocks distant comets loose from their orbits.
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- The most famous of these stellar interloper near misses is called “Scholz’s Star“. This small binary star system was discovered in 2013. Its orbital path indicated that, about 70,000 years ago, it passed through the Oort Cloud, that is the extended sphere of icy bodies that surrounds the fringes of our solar system.
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- Some astronomers even think Scholz’s Star could have sent some of these objects tumbling into the inner solar system when it passed. However, Scholz’s Star is relatively small and rapidly moving, which should have minimized its effect on the solar system.
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- In recent years, scientists have been finding that these kinds of encounters happen far more often than once expected. Scholz’s Star wasn’t the first flyby, and it won’t be the last. In fact, we’re on track for a much more dramatic close encounter in the not-too-distant future.
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- Scholz’s Star probably didn’t have a huge impact, but there should be many more stars that have passed through that are more massive. The record-breaking asteroid “2020 QG” won't soon forget its run-in with Earth.
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- Were you awake early Sunday morning , August 16, 2020, the car-sized “2020 QG” asteroid zoomed just 1,830 miles above the Indian Ocean, making the closest known flyby by an asteroid that didn't end up slamming into our planet.
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- Though 2020 QG survived the encounter, its path through space was altered significantly. Calculations show that this asteroid got turned by 45 degrees as it swung by our planet.
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- Researchers didn't learn of 2020 QG's existence until the ‘Zwicky Transient Facility“, a survey telescope in Southern California captured an image of the asteroid zooming away from Earth, six hours “after” its closest approach.
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- The space rock was rocketing along at 29,000 miles per hour. As speedy as that is, it's a little slower than average for a near-Earth asteroid. There are many millions of near-Earth asteroids out there about the same size as 2020 QG, which is thought to be 10 to 20 feet wide. Such tiny space rocks are very hard to detect, but they pose no danger to life on Earth.
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- If 2020 QG had actually been on an impact trajectory, it would likely have become a fireball as it broke up in Earth's atmosphere, which happens several times a year. “Fireballs” are meteors that blaze more brightly than Venus in our skies.
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- Big asteroids are a bit more worrisome. Scientists think a 6-mile-wide space rock did in the dinosaurs when it barreled into Earth 66 million years ago.
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- NASA has found and tracked more than 95% of the mountain-sized asteroids in Earth's neighborhood, and none of them pose an impact risk in the foreseeable future. The space agency is currently working to compile a similarly comprehensive catalog of the near-Earth asteroids at least 460 feet wide, which would do devastating damage on a regional scale if they hit.
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- A wandering star passed within one light-year of the Sun roughly 70,000 years ago. At the time, modern humans were just beginning to migrate out of Africa, and Neanderthals were still sharing the planet with us.
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- In 2018 Gaia satellite data was used to plot our Sun’s future meet-ups with other stars. Astronomers discovered nearly 700 stars that will pass within 15 light-years of our solar system over just the next 15 million years.
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- The vast majority of close encounters have yet to be discovered, but roughly 20 stars should pass within just a couple light-years of us every million years. “Space is big,”. Statistically, most of those stars would pass the outer edge of our solar system. That means encounters like the one with Scholz’s Star are common, but only a few are close enough to actually dislodge a significant number of comets.
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- A few stars should still come surprisingly close. And if a large, slow-moving star did pass through the edge of the Oort Cloud, it could really shake up the solar system.
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- Many nearby stars will pass close to the Oort Cloud, but only one will move through it. In about 1.35 million years, Gliese 710 likely will gravitationally perturb millions of comets, sending a sizable number on a potential collision course with Earth.
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- A massive star steamrolling through the outer solar system is exactly what Gaia data show will happen less than 1.4 million years from now, according to a 2016 study. A star called Gliese 710 will pass within 10,000 astronomical units.
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- “1 AU” is equal to the average Earth-Sun distance of 93 million miles. That’s well within the outer edge of the Oort Cloud.
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- At half the mass of the Sun, Gliese 710 is much larger than Scholz’s Star, which is just 15 percent the mass of the Sun. This means Gliese 710’s hulking gravity could potentially wreak havoc on the orbits of icy bodies in the Oort Cloud.
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- While Scholz’s Star was so tiny it would have been barely visible in the night sky, Gliese 710 is larger than our current closest neighbor, Proxima Centauri. So when Gliese 710 reaches its closest point to Earth, it will burn as a brilliant orange orb that will outshine every other star in our night sky.
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- This event could be the strongest disrupting encounter in the future and history of the solar system. Fortunately, the inner solar system is a relatively tiny target, and even if Gliese 710 does send comets flying our way, it would take millions of additional years for these icy bodies to reach us.
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- That should give any surviving future humans plenty of time to take action. In the meantime, enjoy watching what may be one of the closest stellar flybys in the history of our solar system. Or, did you miss it. It missed you. Happy Thanksgiving.
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- November 25, 2020 ASTEROID - near miss? 2916
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