Asteroids & Comets

Message boards : Science (non-SETI) : Asteroids & Comets
Message board moderation

To post messages, you must log in.

Previous · 1 . . . 18 · 19 · 20 · 21 · 22 · 23 · 24 . . . 28 · Next

AuthorMessage
Profile Bob DeWoody
Avatar

Send message
Joined: 9 May 10
Posts: 3387
Credit: 4,182,900
RAC: 10
United States
Message 1881860 - Posted: 3 Aug 2017, 15:27:56 UTC - in response to Message 1880897.  

Asteroid 2012 TC4 may be slightly larger than the space rock that hit Earth's atmosphere near Chelyabinsk, Russia, in February 2013.
No biggie so to speak.
https://www.jpl.nasa.gov/news/news.php?feature=6906/

That depends on where it hits.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
ID: 1881860 · Report as offensive     Reply Quote
Profile Bob DeWoody
Avatar

Send message
Joined: 9 May 10
Posts: 3387
Credit: 4,182,900
RAC: 10
United States
Message 1881862 - Posted: 3 Aug 2017, 15:29:50 UTC

I wonder how many asteroids fall into one of earths vast oceans and if the most common ones that make it to the surface can generate a big wave.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
ID: 1881862 · Report as offensive     Reply Quote
Profile William Rothamel
Avatar

Send message
Joined: 25 Oct 06
Posts: 3756
Credit: 1,999,735
RAC: 4
United States
Message 1881940 - Posted: 3 Aug 2017, 23:14:28 UTC - in response to Message 1881892.  

There was one overhead in Key West Florida which exploded and hissed by in flames. I saw it as we were about to march in for the sacrament of confirmation. The Navy said it landed in the ocean around Cuba --100 miles away. Size was indeterminate as you had no frame of reference to judge it's height.
ID: 1881940 · Report as offensive     Reply Quote
rob smith Crowdfunding Project Donor*Special Project $75 donorSpecial Project $250 donor
Volunteer moderator
Volunteer tester

Send message
Joined: 7 Mar 03
Posts: 22161
Credit: 416,307,556
RAC: 380
United Kingdom
Message 1882004 - Posted: 4 Aug 2017, 7:51:28 UTC

The trouble is most of the ICBMs are not designed to be launched into space, only to enter low earth parabola - one would want to hit the rock when it was at least four or five times the earth-moon distance away (preferably a few tens would be better).
Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?
ID: 1882004 · Report as offensive     Reply Quote
Michael Watson

Send message
Joined: 7 Feb 08
Posts: 1383
Credit: 2,098,506
RAC: 5
Message 1882049 - Posted: 4 Aug 2017, 13:40:40 UTC - in response to Message 1881997.  

We do have the NEO program now, but if a real biggie headed our way, we'd know it was coming but not be able to do much about it. The most we could do with current technology is fire all out ICBM and nuclear stuff at it hoping to break it into smaller fragments.

The last big one was in the Chicxulub crater in the Yucatan Peninsula 65 million years ago, that wiped out the dinosaurs, and 75% of plant and animal life on earth. It was estimated to be 6-9 miles in diameter, and carved out a crater 110 miles in diameter and believed to be 12 miles deep.


The heavy lift rockets used to send space probes beyond Earth orbit would be needed, with as large nuclear warheads as they could carry, on top. Adapting nuclear warheads to these rockets might prove difficult.

It would probably be better to detonate the warhead a little distance from the asteroid, so as to push it slightly off course, making it miss us. Breaking it up would take up much of the energy, reducing the diversion effect. It would also be unpredictable. If the asteroid could be reduced to pebbles, fine. What if it was more durable, and merely split into a number of large pieces, all headed our way? That could be almost as bad as leaving it alone.
ID: 1882049 · Report as offensive     Reply Quote
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 1883127 - Posted: 11 Aug 2017, 7:22:25 UTC

According to NASA 2012 TC4 will pass at 44000 km from Earth.
Tullio
ID: 1883127 · Report as offensive     Reply Quote
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 1884667 - Posted: 18 Aug 2017, 7:22:11 UTC

Asteroid Florence, named after Florence Nightingale, will pass at 7 million km from Earth on September 1. It is 4.4 km wide and could be a real danger if closer.It will be tracked by radio/radar telescopes at Goldstone and Arecibo.
Tullio
ID: 1884667 · Report as offensive     Reply Quote
Profile Lynn Special Project $75 donor
Volunteer tester
Avatar

Send message
Joined: 20 Nov 00
Posts: 14162
Credit: 79,603,650
RAC: 123
United States
Message 1897519 - Posted: 26 Oct 2017, 6:22:54 UTC - in response to Message 1884667.  

From Lyra??


We may have just seen the first comet from another solar system


The solar system may be hosting a visitor from the stars. A newly discovered comet is screaming away from Earth, and based on its weird orbital trajectory astronomers think it might be the first comet ever observed that came from interstellar space. A sky-surveying telescope in Hawaii spotted the fast-moving object, now called C/2017 U1, on 18 October, after its closest approach to the sun.

Michael started a thread on this Comet. Posting for posterity.
ID: 1897519 · Report as offensive     Reply Quote
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 1908805 - Posted: 24 Dec 2017, 18:11:23 UTC
Last modified: 26 Dec 2017, 3:10:29 UTC

Arecibo is again working as a radar and has monitored Phaeton 3200 on 16 December. What is funny is that the caption of the images says that Phaeton 3200 was at 1.8 million km from the Earth, while the following text says that Phaeton3200 was at 10 million km from the Earth. Anyway, welcome Arecibo!
Tullio
ID: 1908805 · Report as offensive     Reply Quote
moomin
Avatar

Send message
Joined: 21 Oct 17
Posts: 6204
Credit: 38,420
RAC: 0
Sweden
Message 1909153 - Posted: 27 Dec 2017, 11:33:52 UTC - in response to Message 1908805.  


Observations of Phaethon were conducted at Arecibo from Dec.15 through 19, 2017. At time of closest approach on Dec. 16 at 3 p.m. PST (3 p.m. EST, 11 p.m. UTC) the asteroid was about 1.1 million miles (1.8 million kilometers) away, or about 4.6 times the distance from Earth to the moon. The encounter is the closest the object will come to Earth until 2093.
https://www.nasa.gov/feature/jpl/arecibo-radar-returns-with-asteroid-phaethon-images
ID: 1909153 · Report as offensive     Reply Quote
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 1909156 - Posted: 27 Dec 2017, 12:03:42 UTC - in response to Message 1909153.  

If you read the text, not the caption, it was at10 million km from the Earth.
Tullio
ID: 1909156 · Report as offensive     Reply Quote
moomin
Avatar

Send message
Joined: 21 Oct 17
Posts: 6204
Credit: 38,420
RAC: 0
Sweden
Message 1909157 - Posted: 27 Dec 2017, 12:42:22 UTC - in response to Message 1909156.  

I didn't notice that:)
And it was about 27 times the distance from Earth to the moon.
Not 4.6 times the distance from Earth to the moon as the caption says.
ID: 1909157 · Report as offensive     Reply Quote
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 1909235 - Posted: 28 Dec 2017, 7:07:30 UTC - in response to Message 1909157.  

This again demonstrates the usefulness of Arecibo radar in monitoring Near Earth Objects.
Tullio
ID: 1909235 · Report as offensive     Reply Quote
moomin
Avatar

Send message
Joined: 21 Oct 17
Posts: 6204
Credit: 38,420
RAC: 0
Sweden
Message 1909238 - Posted: 28 Dec 2017, 7:40:38 UTC - in response to Message 1909235.  

This again demonstrates the usefulness of Arecibo radar in monitoring Near Earth Objects.
Tullio

And that NASA need someone that proofread their articles:)
ID: 1909238 · Report as offensive     Reply Quote
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 1909268 - Posted: 28 Dec 2017, 14:51:54 UTC

Proofreading has been abolished by most publishing houses.New books and articles are printed from magnetic medias, with all errors included. This is called progress.
Tullio
ID: 1909268 · Report as offensive     Reply Quote
Michael Watson

Send message
Joined: 7 Feb 08
Posts: 1383
Credit: 2,098,506
RAC: 5
Message 1909280 - Posted: 28 Dec 2017, 16:03:12 UTC

That looks like a large crater, rotating into view at the top edge of the image, near the end of the sequence.
ID: 1909280 · Report as offensive     Reply Quote
moomin
Avatar

Send message
Joined: 21 Oct 17
Posts: 6204
Credit: 38,420
RAC: 0
Sweden
Message 1909322 - Posted: 28 Dec 2017, 20:56:40 UTC - in response to Message 1909280.  

That looks like a large crater, rotating into view at the top edge of the image, near the end of the sequence.
Yes.
On its surface near the equator there is a large depression with a diameter of several meters, as well as a dark circular formation near one of its poles.
The black “Spot” can be a crater or just a hollow. The diameter of the object is 6 km, 1 km more than previously thought.
ID: 1909322 · Report as offensive     Reply Quote
Profile Lynn Special Project $75 donor
Volunteer tester
Avatar

Send message
Joined: 20 Nov 00
Posts: 14162
Credit: 79,603,650
RAC: 123
United States
Message 1913567 - Posted: 17 Jan 2018, 20:02:23 UTC - in response to Message 1909322.  

A gigantic asteroid which is larger than the world's tallest building, the Burj Khalifa, will hurtle past our planet in around two weeks time.

The 2002 AJ129 asteroid has been classed a 'potentially hazardous' by Nasa and will fly past at speeds of 67,000mph (107,826kmh).

This makes it nearly 15 times faster than the world's quickest manned aircraft - the hypersonic North American X-15, which travelled at 4,520mph (7,300kmh).

It will pass.
ID: 1913567 · Report as offensive     Reply Quote
Michael Watson

Send message
Joined: 7 Feb 08
Posts: 1383
Credit: 2,098,506
RAC: 5
Message 1913619 - Posted: 17 Jan 2018, 22:23:02 UTC

As an interesting contrast, a quite small asteroid called 2018 AV 2, about 8 meters in diameter, recently passed within 2.7 times the distance of the Moon. The only really noteworthy thing about it was its velocity.

This was remarkably low , 0.10 kilometers per second, or 360 kilometers per hour. That's less than one percent the velocity of next slowest Near Earth Object, as far as I could discover.

One assumes that the object's orbit must closely resemble that of the Earth, yet the 2018 part of it's name indicates that it was only discovered earlier this month.
ID: 1913619 · Report as offensive     Reply Quote
moomin
Avatar

Send message
Joined: 21 Oct 17
Posts: 6204
Credit: 38,420
RAC: 0
Sweden
Message 1913903 - Posted: 19 Jan 2018, 3:10:53 UTC - in response to Message 1913619.  
Last modified: 19 Jan 2018, 3:21:13 UTC

And a newly discovered asteroid designated 2018 BD flew past Earth at a very close distance of 0.10 LD / 0.00026 AU (~38 895 km / 24 168 miles) at 15:43 UTC on January 18, 2018, some 7 hours after it was discovered. This is the fourth closest approach to our planet since 2017 EA on March 02, 2017, 2017 GM on April 4, 2017, and 2017 UJ2 on October 20, 2017.
https://www.cnet.com/news/asteroid-2018-bd-earth-potentially-hazardous-2002-aj129/
2018 BD is a newly discovered car-size asteroid that passed us on Thursday -- coming near the altitude where many man-made satellites orbit -- and hardly anyone noticed.
ID: 1913903 · Report as offensive     Reply Quote
Previous · 1 . . . 18 · 19 · 20 · 21 · 22 · 23 · 24 . . . 28 · Next

Message boards : Science (non-SETI) : Asteroids & Comets


 
©2024 University of California
 
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.