Daily Mail 7 Sep 2016:
Phew! Large 32ft asteroid passed just 40,000km from our planet today – Ten times nearer to Earth than the moon
Asteroid came within a distance of 24,800 miles (40,000 km)
The 32ft-long asteroid passed by Earth today at 18:12 BST (13:12 ET)
Closest a space rock will come to Earth for at least the next half century
I created a short YouTube video showing the view of the Earth from asteroid 2016 RB1 as it approached, passed under the south pole of the Earth at 17:20 GMT on 7 Sep 2016, and continued on past.
The red line is the ecliptic, through which the asteroid passes twice. The faint grey lines are parts of constellations.
The disturbing thing about asteroid 2016 RB1 is that it not only came as close to the Earth as asteroid 2012 DA14 in February 2013, but it was also only slightly smaller than the rock that landed on Chelyabinsk on the same day in 2013, and it was only discovered in the early hours of 5 Feb 2016, less than 2 days before its closest approach to the Earth. There was next to no warning.
There’s a chance of about 2.5% that a rock that gets closer than 40,000 km from the Earth will actually impact it. That’s a 1 in 40 chance. About 70% of the surface of the Earth is covered by oceans or seas, so most likely the one in 40 chance impactor would land in water.
Sooner or later there’s going to be another Chelyabinsk-type event. I wonder if there are procedures in place as to what to do if an asteroid like 2016 RB1 had been on course for Paris or New York in 40 hours time. Would they broadcast the news, and spark a panic that would result in gridlocked streets and refugees on foot?
Also, accurate measurements need to be made before the size and trajectory of a newly-discovered asteroid can be accurately determined, and its likely impact point ascertained. By the time it arrived, there might still be a lot of uncertainty.
I somehow imagine that public broadcasting would downplay the risks, while the ‘top people’ would be quietly spirited out of the area. But then the information would probably get leaked or hacked, and released by Wikileaks…
Since one of my interests is in whether these asteroids can have companions, I’ve kept an eye out for fireball reports. And there was a large daylight fireball over N Carolina on 8 Sep at about 22:00 GMT, seen by about 180 people, and estimated to been moving roughly north to south (right).
So I created a cloud of companions around 2026 RB1, with each rock having the same direction and speed as it, and found that one of them could have landed on N Carolina at 22:00 GMT, travelling north-east to south-west (marked as a blue-green fleche below).
That’s actually quite a good fit, if the kind of reporting inaccuracies I found a few days ago are taken into consideration.
P.S. There’s another fireball report from Cyprus on the night of 8 Sep 2016 at 12:36 (local time). The video shows a single bright flash.
An RB1 companion can impact Cyprus. The atmospheric trajectory is shown as a red line below, and the ground track a blue line. The shortness of the blue line relative to the red line indicates that this is a very steep impact. Such steep impacts tend to result in an explosion or bright flash.
In another report,
“It had a 45 degree tilt and a bang was heard as it passed over Cyprus,” Cyprus astronomical society honorary chairman Ioannis Fakas told Reuters. He explained that parts of the meteorite are believed to have hit the sea north of Cyprus, adding that the object likely didn’t weigh over a few kilos.”
This suggests that the the meteorite was moving from south to north.