Asteroids sneaking up on Earth? + Dark matter asteroids may cause solar flares

#1
C C Offline
Why are asteroids sneaking up on Earth?
https://thedebrief.org/why-are-asteroids...-on-earth/

EXCERPT: . . . After analyzing data from previous NEO events, researchers from the University of Hawai’i (UH) noted that due to a quirk in the Earth’s rotation, NEOs like the one that just missed Earth in 2019 can appear stationary to detection satellites if they approach from the east, particularly in the nighttime sky between midnight and 2 a.m. As such, the satellite network that looks for these types of objects dismisses the NEO as something stationary, instead of marking them as the potentially imminent threat they may actually be.

“Surveys should take extra care when surveying the sky in this direction, and aggressively follow up new slow-moving objects,” reads the research published in the journal Icarus.

UH Professor Richard Wainscoat, who led the research team behind the latest discovery, said people “shouldn’t lose sleep” over fears of an asteroid hitting Earth. However, he noted, “In the event that we find something that is going to hit the earth we would like to do something about it.”

“It’s not a matter of finding them and sitting there and letting it hit,” explained Wainscoat of the survey and detection effort.

The Debrief previously reported on NASA’s DART mission, which will test the ability of a human spacecraft to change the trajectory of such an object by slamming into an asteroid later this year. If such technology is expected to protect earth from a potentially catastrophic NEO, a detection window of four weeks may be enough time to act.... (MORE - missing details)


Dark matter asteroids (if they exist) may cause solar flares
https://arstechnica.com/science/2022/01/...ar-flares/

EXCERPT: . . . If it's true that dark matter can form structures, there are probably asteroids of dark matter flying around the Universe. Occasionally, dark matter asteroids will collide with stars, and then things get very exciting.
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Dark matter in an asteroid interacting with real matter in a star basically amounts to unity (because stars are rather dense). Based on what we know about the Universe and how galaxies form, dark matter asteroids have to be moving very fast.

"Fast," in this case, means "faster than the speed of sound within a star." So when an asteroid hits a star, it produces a cylindrically shaped acoustic shock wave. The star acts as an acoustic lens—a star is less dense and bends acoustic rays toward the surface—so the shock wave is loosely focused around the entry point of the asteroid.

This process acts to intensify the shock wave in a local region rather than letting it spread out. Then, as the shock wave gets closer to the surface, its speed (relative to the speed of sound) gets higher, making its effect on the stellar medium greater.

These two processes are sufficient to cause the star to emit a burst of X-rays, with a tail of emission extending into visible light. In other words, there is a burst of light that is definitely visible to our observational tools.
Solar flares are common

The researchers used the estimated dark matter density of a globular cluster called 47 Tuc to calculate how often flares induced by dark asteroids would be visible to the Hubble Space Telescope (if it had the right filters in place). The scientists concluded that a week of observation time should be sufficient to detect flares... (MORE - details)
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#2
Magical Realist Offline
I don't know that there will be enough thrust from a satellite to shove a large asteroid off course from earth. Seems like more and more of these are sneaking up on us more often. I despair that the human race's days are numbered. We have no idea when. But it will happen eventually. This may be the answer to the Fermi paradox. No species ever evolves far enough to avoid the inevitability of asteroid impact.
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#3
Kornee Offline
(Jan 19, 2022 05:38 PM)C C Wrote: ...Dark matter asteroids (if they exist) may cause solar flares
https://arstechnica.com/science/2022/01/...ar-flares/

EXCERPT: . . . If it's true that dark matter can form structures, there are probably asteroids of dark matter flying around the Universe. Occasionally, dark matter asteroids will collide with stars, and then things get very exciting.
Advertisement

Dark matter in an asteroid interacting with real matter in a star basically amounts to unity (because stars are rather dense). Based on what we know about the Universe and how galaxies form, dark matter asteroids have to be moving very fast.

"Fast," in this case, means "faster than the speed of sound within a star." So when an asteroid hits a star, it produces a cylindrically shaped acoustic shock wave. The star acts as an acoustic lens—a star is less dense and bends acoustic rays toward the surface—so the shock wave is loosely focused around the entry point of the asteroid.

This process acts to intensify the shock wave in a local region rather than letting it spread out. Then, as the shock wave gets closer to the surface, its speed (relative to the speed of sound) gets higher, making its effect on the stellar medium greater.

These two processes are sufficient to cause the star to emit a burst of X-rays, with a tail of emission extending into visible light. In other words, there is a burst of light that is definitely visible to our observational tools.
Solar flares are common

The researchers used the estimated dark matter density of a globular cluster called 47 Tuc to calculate how often flares induced by dark asteroids would be visible to the Hubble Space Telescope (if it had the right filters in place). The scientists concluded that a week of observation time should be sufficient to detect flares... (MORE - details)

Seems oxymoronic by definition. All observations afaik point to dark matter as non-interacting (apart from gravity) with ordinary matter or itself. Hence has the characteristics of an inert dark gas.
Gravity wouldn't allow DM 'asteroids' to form.
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