Author Topic: NASA: Previously Unknown Asteroid had a Near Miss with Earth today  (Read 1262 times)

Offline walkstall

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They need to be looking at space not Trump.   :lol:

snip~
SURPRISE ASTEROID FLYBY: With little warning, on Sunday, April 15th, a “Tunguska-class” asteroid about the size of a football field flew through the Earth-Moon system. 2018 GE3 was discovered just the day before as it plunged inward from the asteroid belt. A quick-thinking amateur astronomer in Europe was able to record a video of the asteroid as it flew by.

more @
https://wattsupwiththat.com/2018/04/15/nasa-previously-unknown-asteroid-nearly-misses-earth-today/
A politician thinks of the next election. A statesman, of the next generation.- James Freeman Clarke

Politics is supposed to be the second-oldest profession.  I have come to realize that it bears a very close resemblance to the first.  ~ Ronald Reagan ~

Always remember "Feelings Aren't Facts."

Offline |Glitch|

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Re: NASA: Previously Unknown Asteroid had a Near Miss with Earth today
« Reply #1 on: May 12, 2018, 10:15:27 AM »
As of  March 1, 2018 NASA has discovered 17,785 Near Earth Objects (NEOs).  Currently NASA is tracking 911 NEOs that are 1 km or larger, and as of 2017 NASA estimates that there are 921 ± 20 NEOs that are 1 km or larger.  Which places the percentage of known NEOs that are 1 km or larger at 98.9%.

Unfortunately, it gets worse from there.  The estimated number of NEOs greater than 140 m is 27,100 ± 2,200.  NASA has discovered 8,066 NEOs that are larger than 140 m, and smaller than 1 km, or 29.8%.  The estimated number of NEOs greater than 40 m, but smaller than 140 m in diameter is 840,000 ± 23,000, of which NASA has discovered 1.3%.

Depending upon the density and composition of the asteroid, they need to be at least 25 m in diameter to reach the surface of the planet.  There are literally millions of NEOs that are big enough to wipe out a major city that we know nothing about.  We have been very fortunate thus far, but it won't last.  Some suggest that a Tunguska-sized event may occur every 300 years.

Sources:
The Near-Earth Asteroid Population from Two Decades of Observations - Icarus, Volume 284, Issue 1, 2017
Absolute Magnitudes of Asteroids and a Revision of Asteroid Albedo Estimates from WISE Thermal Observations - Icarus, Volume 221, Issue 1, 2012
Earth in the Cosmic Shooting Gallery - The Observatory, Volume 125, 2005

Offline Rotwang

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Re: NASA: Previously Unknown Asteroid had a Near Miss with Earth today
« Reply #2 on: June 08, 2018, 08:42:46 PM »
They need to be looking at space not Trump.   :lol:

snip~
SURPRISE ASTEROID FLYBY: With little warning, on Sunday, April 15th, a “Tunguska-class” asteroid about the size of a football field flew through the Earth-Moon system. 2018 GE3 was discovered just the day before as it plunged inward from the asteroid belt. A quick-thinking amateur astronomer in Europe was able to record a video of the asteroid as it flew by.

more @
https://wattsupwiththat.com/2018/04/15/nasa-previously-unknown-asteroid-nearly-misses-earth-today/


Doesn't this happen pretty much every week ?


Now I don't want a REALLY BIG one, but a few smaller, well-placed asteroids could do us a would of good.


Cough Cough …


Sacramento, Albany, DC (when Trump is on a trip), Chicago, St Louis, et al.....

Offline |Glitch|

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Re: NASA: Previously Unknown Asteroid had a Near Miss with Earth today
« Reply #3 on: June 09, 2018, 05:11:03 AM »
We know what NASA has discovered, but what we don't know is how many of those discovered NEOs that have subsequently been lost.  It is estimated that just over 100 tons of primarily sand-sized particles to as big as basketball-sized objects impact our planet daily.  Car- to bus-sized asteroids appear regularly as fireballs, a.k.a. bolides.

It isn't a question of "if" Earth will be impacted by a meteorite larger than 50 meters, it is only a question of "when."  The more we populate this world the greater the threat they become.   The Tunguska event in Yeniseysk Governorate, Russia, in 1908 occurred over a very sparsely populated area.  Had it occurred just a few hours earlier it would have exploded over London.  London had a population of 6.7 million in 1908.  Just think what an event like that would do today.

Just on a whim, I ran the numbers for a 140 meter diameter radius asteroid with the density of 3 g/m3, at an angle of 45° with a velocity of 20 km/s.  The resulting impact would yield a 206 mega-tonne explosion.  Should it occur on the White House (when the President was not there obviously), it would result in approximately 5,104,480 deaths, and another 5,889,380 injured.

The crater itself would be 2.61 km in diameter and 556 meters deep.  The only good news is that an impact does not create much of a fireball, so there is very little damage caused by thermal radiation.  The air blast combined with the magnitude 6.0 earthquake, however, will take buildings down for ~40 miles around the epicenter.

Sources:
Impact Earth! - Purdue University
Nuke Map - by Alex Wellerstein

140 meter diameter asteroid was chosen because that is was the smallest size Congress ordered NASA to look for in 2008.  Depending on the density and composition of the asteroid it only needs to be 50 meters in diameter or larger to actually impact the planet.

Nuke Map only allows for a maximum value of 100 mega-tonnes, therefore the values used in the above example were doubled, and no radiation casualties were included.
« Last Edit: June 09, 2018, 05:20:21 AM by |Glitch| »

Online Sick Of Silence

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First Amendment isn't just Freedom Of Speech, it's Freedom Of Conscience.

Who made you the arbiter of morality? You are not Government but you sure are acting like one.

Online Sick Of Silence

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First Amendment isn't just Freedom Of Speech, it's Freedom Of Conscience.

Who made you the arbiter of morality? You are not Government but you sure are acting like one.

 

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