A car-d asteroid made the closest Earth flyby a space rock has ever survived

[Admin]

An asteroid flew by Earth at just 1,830 miles (2,950 kilometers) away.

A car-d asteroid made the closest Earth flyby a space rock has ever survived : Read more

 

[JPL-ACE]

I guess the distance reported is to the surface of the Earth. Earth being about 4000 mi in radious. It seems od that is the closest "miss" ever recorded. The astroid that lit up Russia a few years ago hit the atmosphere and that is only about 60 miles high. Would be cool to see one cut it that close (but no closer).

 

[Wolfshadw]

I guess the distance reported is to the surface of the Earth. Earth being about 4000 mi in radious. It seems od that is the closest "miss" ever recorded. The astroid that lit up Russia a few years ago hit the atmosphere and that is only about 60 miles high. Would be cool to see one cut it that close (but no closer).

I think that if they get much closer than that (not sure how close), they get caught in Earth's gravity and are pulled in. I don't know any of the math, but I'm sure angle of approach as well as velocity play into whether it misses or gets caught.

-Wolf sends

 

[ardallas]

The article title sounds cool, but is inaccurate. Earth-grazing meteors are well documented, and are surely "space rocks".

 

[rod]

2020 QG. the orbital elements can be found here for this object. https://www.minorplanetcenter.net/mpec/K20/K20Q51.html

Semi-major axis is 1.9138 AU, e = 0.487, period = 2.68 years. The asteroid perihelion distance is near 0.99 AU.

 

[newtons_laws]

The article title sounds cool, but is inaccurate. Earth-grazing meteors are well documented, and are surely "space rocks".

Correct, there is film footage of at least one space rock partially entering the Earth's atmosphere causing a grazing fireball which then ceased as the rock skipped back out of the atmosphere e.g the daylight fireball of 1972 a few frames of which were caught on a cine camera:

View: https://www.youtube.com/watch?v=4WlCfuPrszU

 

[Helio]

I think that if they get much closer than that (not sure how close), they get caught in Earth's gravity and are pulled in. I don't know any of the math, but I'm sure angle of approach as well as velocity play into whether it misses or gets caught.

Yes angle and velocity are likely huge factors.

I would assume the closest fly-bys would be those that skip off the atmosphere. The Shuttle needed about a 40 deg. approach angle to avoid skipping off, IIRC. Perhaps asteroids are less aerodynamic, but even a round rock would skip off water if thrown fast enough and low enough.

 

[RichardMathews]

The article title sounds cool, but is inaccurate. Earth-grazing meteors are well documented, and are surely "space rocks".

Eight earth grazers are listed here.

Earth-grazing fireball - Wikipedia

en.wikipedia.org

 

[timofeysie]

Correct, there is film footage of at least one space rock partially entering the Earth's atmosphere causing a grazing fireball which then ceased as the rock skipped back out of the atmosphere e.g the daylight fireball of 1972 a few frames of which were caught on a cine camera:

View: https://www.youtube.com/watch?v=4WlCfuPrszU

I was thinking the same thing. US19720810 "1972 Great Daylight Fireball" was a lot closer. This might even be the same rock, that might have been here again in 1997. But why does the news reports keep saying that 2020 QG was the closest ever?

 

[newtons_laws]

I was thinking the same thing. US19720810 "1972 Great Daylight Fireball" was a lot closer. This might even be the same rock, that might have been here again in 1997. But why does the news reports keep saying that 2020 QG was the closest ever?

Because the writer of the article isn't as well informed as we are.....

 

[Brookeok]

Correct, there is film footage of at least one space rock partially entering the Earth's atmosphere causing a grazing fireball which then ceased as the rock skipped back out of the atmosphere e.g the daylight fireball of 1972 a few frames of which were caught on a cine camera:

View: https://www.youtube.com/watch?v=4WlCfuPrszU

I was curious about that very incident too. I wrote NASA and was informed that the 72 fireball was considered an impact since it did interact with the atmosphere. Even so, it did survive it's interaction so their qualification was not entirely accurate. I was surprised that no one mentioned that incident at all since both objects were similar in size.

 

[Helio]

I was curious about that very incident too. I wrote NASA and was informed that the 72 fireball was considered an impact since it did interact with the atmosphere. Even so, it did survive it's interaction so their qualification was not entirely accurate.

That's a little surprising.

The IAU definition states, "If the meteoroid survives the meteor phase without being completely vaporised, it is then called a meteorite."

So, by definition, a skipping meteor becomes a meteorite even though it returns to orbit, albeit diminished (object and orbit). I suspect that they should've included the object hitting the surface to be a meteorite, right? When forming the definition, it seems they just skipped the skippers.

 

[Catastrophe]

Rod "The asteroid perihelion distance is near 0.99 AU."

Correct to how many significant figures?