Posted on 09/22/2020 6:54:35 PM PDT by BenLurkin
Scientists have yet to pin down the asteroid's exact size, but it's not that large, likely between 14 feet and 32 feet (4.4 and 9.9 meters) long, according to CNEOS. This potentially RV-size asteroid was discovered only last week, on Sept. 18, by the Mount Lemmon Survey in Arizona, and announced the next day by the Minor Planet Center, a NASA-funded group that monitors minor planets, comets and natural satellites. (It's not unusual to find unknown asteroids; in September alone, the Minor Planet Center has announced the discovery of 244 near-Earth objects.)
Passing by Earth will actually be a life-changing event for asteroid 2020 SW. It's such a small asteroid that Earth's gravity is expected to change the space rock's course when it zooms by our planet at 7:18 a.m. EDT (11:18 UTC), according to EarthSky.
After asteroid 2020 SW's close shave with Earth, it won't pay our planet another visit until June 3, 2029, according to the Jet Propulsion Laboratory.
That said, the asteroid is certainly rushing to see us this Thursday..., traveling at a velocity of about 17,200 mph (27,720 km/h, or 7.7 km/second) relative to Earth, the Jet Propulsion Laboratory reported.
The asteroid will appear brighter as it nears Earth, but it won't be visible to the naked eye. If you want a clear view of the space rock, visit The Virtual Telescope website, which is showing a live feed starting at 6 p.m. EDT (22:00 UTC) on Wednesday, Sept. 23.
(Excerpt) Read more at livescience.com ...
“RV-size asteroid to get closer to Earth than the moon”
—
Someone needs to work on writing clearer headlines.
Calling the US Space Command. “Incoming”. Light ‘er up!
Probably both bodies are moving so as to make for interesting calculations for our space scientists.
How big was the Chelyobinsk (sp?) space object that broke thousands of windows in Russia before it entered the earth’s atmosphere?
Wikipedia says 20m; that caused localized property damage and injuries but no deaths. This is what the Torino Scale suggests would happen.
Bigger than this, but was mostly ice, so it hit its roche point and/or was shaken to detonation by its rapid passage through the atmosphere.
http://www.freerepublic.com/tag/chelyabinsk/index?tab=articles
Ah:
http://www.freerepublic.com/focus/chat/3145261/posts
[snip] Chelyabinsk, a large city in western Russia, was best known for producing tractors and professional hockey players until the morning of February 15, 2013, when a 19-meter-wide meteor screamed through the sky and exploded with the force of 500 kilotons of TNT. [/snip]
The “Little Boy” dropped on Hiroshima blew like “13 kilotons”.
The Torino Scale doesn’t suggest anything of the kind, it’s a way of categorizing the level of risk of impact by an object that hasn’t hit yet.
The Chelyabinsk keyword, chrono:
Someone needs to work on writing clearer headlines.
That's actually not ambiguous. After all, the writer did not claim that it was to get closer to the Earth than to the Moon.
However...
(It's not unusual to find unknown asteroids; in September alone, the Minor Planet Center has announced the discovery of 244 near-Earth objects.)
If they only now found them, then of course they were previously unknown. (If they were not unknown - i.e., if they were already-known asteroids - the astronomers couldn't "find" them.)
Regards,
Roche's Limit pertains only to the break-up of small celestial bodies held together only by gravity, and lacking any internal cohesive forces, as though they were made up only of, say, water. The common phrase is "liquid bodies." A satellite made of, e.g., stone or metals would not be affected, even within Roche's Limit.
The fact that our artificial satellites (e.g., the ISS) don't disintegrate although they are well within Roche's Limit attests to this fact.
Regards,
It's such a small asteroid that Earth's gravity is expected to change the space rock's course when it zooms by our planet at 7:18 a.m. EDT (11:18 UTC), according to EarthSky
Apparently the writer doesn't understand gravity very well.* Most any object not many times more massive than the Earth, passing "close" to Earth, will have it's direction changed substantially by Earth's gravity. Of course, if the object is substantial in comparison with Earth, we'll get yanked around too (so to speak). But, anything classified as an asteroid, large or small, will be affected pretty much the same for a given initial vector.
*Why am I not surprised?
Try again:
- - - - -
However...
It's such a small asteroid that Earth's gravity is expected to change the space rock's course when it zooms by our planet at 7:18 a.m. EDT (11:18 UTC), according to EarthSky
Apparently the writer doesn't understand gravity very well.* Most any object not many times more massive than the Earth, passing "close" to Earth, will have it's direction changed substantially by Earth's gravity. Of course, if the object is substantial in comparison with Earth, we'll get yanked around too (so to speak). But, anything classified as an asteroid, large or small, will be affected pretty much the same for a given initial vector.
*Why am I not surprised?
For things that strike the earth, e.g. on the far right of the graph where the probability of impact is basically 100%, you can get a sense for the damage. Things falling on the zero range aren't of global consequence, but that wouldn't mean it wouldn't be problematic locally.
This foots with other graphs/analysis, such as this one (please ignore the y-axis - it's the x-axis that's of interest here):
....effectively giving ranges of expected damage.
No, it doesn't. It is a way of classifying the risk of impact by a known body, not the extent or seriousness of impact. The mass and velocity of the bolide are needed for that, and the mass is rarely known with great precision due to the length of time astronomers can get bead on any one of them.
[wiki] In celestial mechanics, the Roche limit, also called Roche radius, is the distance within which a celestial body, held together only by its own force of gravity, will disintegrate due to a second celestial body’s tidal forces exceeding the first body’s gravitational self-attraction. [/wiki]
The ISS isn’t a celestial body, and isn’t held together by its own gravity.
How much closer than 240K miles?
The x-axis represents the probability of impact or a way of classifying the risk of impact by a known body.
The y-axis represents the kinetic energy released in the event of an impact as a function of the size of the object, or the extent or seriousness of impact.
The intersection of these items yields the expected damage - i.e. probability of impact * damage upon impact.
The colored space on the Torino Scale is a qualitative categorization of the expected damage, and that is akin to a statistical expected outcome function, probability of X * outcome in the event of X. Someone, somewhere, believes the expected damage is qualitatively the same between a massive object with a remote chance of impact and a small object with a high chance of impact.
I don't doubt that a refinement of Torino that integrates the velocity of the object would help. And I also agree that the y- and x-axis values of a objects are frequently updated as we learn more (though this is separate from the values on the axes and colored equivalent ranges). Indeed, as your links and your ping list posts show, we are often "surprised" by the discovery of a NEO right before it whizzes by us, or that a back-test of actual impacts shows how off-base were estimates. That's life in this space (no pun ...TANSTAAFL.
Nonetheless, the Torino Scale captures the likelihood and consequences of a potential impact event, and the compounding of those items is indeed an expected consequence measure. Finally, if impact is definitive (i.e. highest x-axis value), the Red Zone qualitative descriptions aren't wildly off-base.
Get off my Planet!
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