Posted on 02/20/2016 9:05:26 PM PST by Celerity
You may need Java on, also this link has been giving a few people issues.
The link is here (For copy/pasters) http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2013%20TX68&orb=1
Go to www.spaceweather.com and scroll down to the near-earth objects.
2013 TX68 Mar 5 0.044 LD 30 m
“25,000 MPH = 475,200,000,000 ft./second = 144,842,721,287 m/second.”
Sorry, but you’re double dividing, meaning that you’re multiplying when you should be dividing. By your logic if 25,000 MPH is 144,000,000,000 m/second, then 25 MPH would be 144,000,000 m/second (or about a million miles per second, which it clearly is not).
Don’t panic yet. The close-approach number is 0.000207 AU. An AU is 93,000,000 miles (average Earth to sun). Multiply the two and you get about 20,000 miles - same as been advertised...still darn close and still could hit with a slight change in course (or if their calcs are off).
You do get 47 miles if you use the Moon distance for AU (i.e., 231,000 miles), but that is not correct. If it got within 50 miles, the upper atmosphere would snatch it and blow it up - it would be vicious.
Whew, thanks for the clarification.
Brings to mind that the one we were watching wasn’t the one that exploded over Russia but came completely from another direction and totally unexpected and on the same day even. I’m just wondering what’s in the other hand?
25,000 miles per hour times 5280 feet per mile equals 132,000,000 feet per hour. divide by 3600 seconds per hour equals 35,667 feet per second. Divide that by 3.2808 equals 11,176 meters per second.
Going back and plugging that into Ke=1/2 (mv^2), and using the original mass at 160,000 tons (145,454,545 kg) and 25,000 MPH equal to (the corrected value of) 11176 m/s, equals a mere 9,084,073,694,941,999 joules
Much better. since a kiloton of TNT yields 4.184 × 10 9 joules (4,184,000,000 joules) the kinetic energy would be the energy equivalent of roughly 2171 MT of TNT. Still a pretty healthy swat, but not a planet wrecker.
No prob! Sometimes breaking out a pen and paper to write down units helps...even in today’s ‘virtual’ world.
Thanks for the corrections everyone, and most even did so without trying to make me cry. Bravo !
But yeah, I’ve been away just doing other things. Running the company (Which collapsed a few weeks ago) to raising my daughter.
The chart DOES say “LD”. Lunar distance.
When I compared the first number to the yield of a KT of TNT, I was going 'holy sh*t!'
Now, we're looking st something only 10 or so times the highest yield of the largest thermonuclear device ever detonated, and while that's substantial, not all of that energy will necessarily be transferred in such a way or place that it will be devastating.
Our lovely dirtball in space still has a lot of unoccupied territory out there, especially the 70% covered by water. An airburst over a populated region would be a mess, though, depending on altitude and location...
Not sure which chart you’re referring to, but I was using the table in the “Close Approach Data” tab, where it does say AU.
Agree...we probably get hit quite a bit by this size rock. But it’s a SMALL ROCK, and not even know it - the big ones are the game changers though.
Yep. There have been a few planet changing collisions/impacts in the past. Even relatively small events could have significant effects on the human population and civilization as we know it.
It is complex due to all the variables - Mass, Velocity, Angle, Impact site density, etc.
Interesting to play around with.
You and your cyclones.
You may enjoy reading about hypercanes, which, if they have ever existed, might have a shot of ending human society in a large swath of the world. Of course, the only plausible heat source for such a thing would be an asteroid impact. Hypercanes were hypothesized as a side effect of the Chicxulub impact at the K-T boundary.
Storms, no matter how many deaths and how much damage they cause, don’t threaten mass extinction. Unlike impacts from space, people usually have sufficient warning — even in very remote areas — and can seek shelter.
Large impacts from space are so powerful there’s no way to reasonably take cover. We’d all still try, of course.
Impacts — Catastrophism.
Storms — not.
Which book was that? I do know that Jerry Pournelle used that theme.
The Moon Is A Harsh Mistress.
A bullet only goes around 1,700 MPH and look at how much more damage that does at that speed vs. just throwing it. This big rock is going 25,000 MPH!
You are thinking of Lucifer’s Hammer by Larry Niven and JP.
https://en.wikipedia.org/wiki/Lucifer%27s_Hammer
This link has reviews from various reviewers: http://www.goodreads.com/book/show/218467.Lucifer_s_Hammer
Would it matter if you were standing on a corner in Winslow, Arizona?
Read the book I recommended.
There is a war between a lunar colony and earth.
The colonists throw rocks.
Read them both. Why not? They are both good.
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