There's a lot to be scared of on Halloween night, but now you should be adding 2015 TB145 to that list of All Hallow's Eve horrors.
According to NASA, an asteroid with the blood curdling name of 2015 TB145 is expected to pass incredibly close to Earth on Halloween night. In fact, it is the second of two close encounters which will come our way around the end of the month.
What is 2015 TB145?
Discovered on October 10th by the Pan-STARRS 1 observatory, 2015 TB145 is the name of a 320 meter in diameter asteroid which will pass by the Earth at the distance of 0.00326 au or 1.3 lunar distances. For laymen, this is basically 1.3 times the distance between Earth and the moon, or about 490,000km (304,471.884 km). According to NASA:
The asteroid is in an extremely eccentric (~0.86) and high inclination (~40 deg) orbit. It has a Tisserand parameter of 2.937 hinting that it may be cometary in nature... The flyby presents a truly outstanding scientific opportunity to study the physical properties of this object.
It also added:
The encounter velocity is 35 km/s, which is unusually high.
Amateur astronomers might be able to catch a glimpse of the asteroid if they take a gander at the constellation of Taurus on October 31st at around 17:12 UTC. Unfortunately, due to the fact it will be a daytime pass and near the gibbous Moon it will be hard to see without advanced telescopes.
However, this isn't our only close encounter in Halloween week. Two days earlier on the 29th, another asteroid, 2009 FD, will come rather close. 2009 FD will swing by at a distance of 0.0418 au or 16.3 lunar distances. Luckily, NASA has revealed there's nothing to worry about... yet. They stated:
2009 FD is not classified as a "Potentially Hazardous Asteroid" because its absolute magnitude is slightly fainter than the cutoff of 22. WISE and radar observations discussed above show that the diameter is probably at least 300 meters, so it's large enough to be "potentially hazardous" even though it isn't classified as such.
Is There an Asteroid Out There with Our Name on It?
Although we have nothing to fear from 2015 TB145 (unless of course it's some kind of alien craft disguised as a asteroid -- a possibility foolishly ignored by NASA) there are a few asteroids out there which will come extremely uncomfortably close.
In August 2027, 1999 AN10 will pass by at a range of 1 lunar distance than 2015 -- even closer than TB145, but NASA scientists are still fairly certain it doesn't pose a threat. In fact, as far as NASA knows, there is currently no certain Earth-killing candidates out there in space - except perhaps one: 99942 Apophis.
99942 Apophis will pass by Earth several times in the next 50 years or so, and will come incrementally closer each time. When it was first discovered, the 325 meter in diameter asteroid was given a 2.7% chance of hitting the Earth. Subsequent observations have all but eliminated a chance of collision on this first pass on April 13, 2029, although it will come extremely close.
The asteroid will be so close (within our geostationary satellite ring) that it will possibly pass through the gravitational keyhole, an area of space in which earth's gravitational pull will alter the trajectory of an object passing through it. Exactly 11 years later, on April, 2036, the asteroid will make another close pass, just skimming the Earth.
However, this isn't the last we've heard from 99942 Apophis. On April 12, 2068 the asteroid will make another pass, with NASA suggesting there is a 1 in 149,000 chance of it impacting with the Earth. Sure, this doesn't sound like a lot, but the fact there's even a chance is slightly disconcerting.
If we survive that one, then our old friend 2009 FD might wipe us out in 2185 instead. NASA is currently suggesting it has a 1 in 365 chance of impacting the Earth on this date, although calculations are ongoing.
What would it look like if an asteroid struck the Earth? Well, Michael Bay thinks it will look like this:
And these are just the asteroids we know about. As 2015 TB145 shows, NASA and various observatories only discover asteroids when they are already rather close to Earth. Back in 2005, Congress tasked NASA with finding and cataloging 90% of near-Earth objects (NEO) by 2020. Unfortunately, by 2015 they have probably found only 10% of them. NASA Inspector General Paul Martin revealed in a report:
While the program has discovered, categorized, and plotted the orbits of more than 11,000 NEOs since 1998, NASA estimates that it has identified only 10 percent of all asteroids 140 meters and larger and will not meet the 2020 deadline...
The problem, it seems, is two-fold. Firstly, there are simply lots and lots and lots of asteroids out there, while secondly, the funding NASA has received for the task is minute. NASA's NEO project gets around $40 million a year, which in public spending terms in rather tiny -- especially for the task at hand. The movie Armageddon actually had a bigger budget at $200 million (when adjusted for inflation).
But don't worry, let me put your mind at rest. An asteroid WILL hit us one day, that's simply a mathematical certainty. Whether we're here to experience it or not is another question. If you need any proof all you have to remember is that it happened before. Remember that whole extinction of the dinosaurs thing?