546. Death by Meteor

This episode is called Death By Meteor and it’s all about asteroids, space, science, maths, astrophysics and the end of the world! Transcript available.

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Transcript

I’m talking about asteroids and meteors and the possibility that one might strike the earth and what would happen in that situation, or perhaps what will happen in that situation because it is highly likely sooner or later, hopefully later.

There will be lots of English of course! Watch out for vocab on all those topics coming up in the episode, which I will be clarifying for you as we go, because I’m nice like that.
In fact, first of all, here’s a bit of vocab straight off the bat.

What’s the difference between an asteroid and a meteor, a comet and a shooting star?

Oxford dictionary en.oxforddictionaries.com/definition/meteor

Asteroid = A small rocky body orbiting the sun. Large numbers of these, ranging enormously in size, are found between the orbits of Mars and Jupiter, though some have more eccentric orbits.

Meteor = A small body of matter from outer space that enters the earth’s atmosphere, becoming incandescent as a result of friction and appearing as a streak of light.

Shooting star = A small, rapidly moving meteor burning up on entering the earth’s atmosphere

Meteorite = A piece of rock or metal that has fallen to the earth’s surface from outer space as a meteor. Over 90 per cent of meteorites are of rock while the remainder consist wholly or partly of iron and nickel.

Comet = A celestial object consisting of a nucleus of ice and dust and, when near the sun, a ‘tail’ of gas and dust particles pointing away from the sun.

Originating in the remotest regions of the solar system, most comets follow regular eccentric orbits and appear in the inner solar system as periodic comets, some of which break up and can be the origin of annual meteor showers. They were formerly considered to be supernatural omens.

There’s a lot of talk about what’s going on here on earth relating to the political situation – lots of squabbles going on between people.

It looks like we’re facing a pretty troubled time, and maybe we’re going to spoil everything for ourselves by blowing each other to smithereens, crashing the economy or just ruining the lives of most ordinary people to the point that the world becomes a post-apocalyptic wasteland where the super-rich 0.1% live in protected biodomes in space or something.

Like T800 says in Terminator 2 “You are humans. It is within your nature to destroy yourselves”

However, perhaps before we manage to do that, we might in fact go the way of the dinosaurs, and end up being wiped out by environmental factors, and this includes the very real threat of climate change and how that can affect the careful balance of life on earth, or by some geological event like the eruption of a supervolcano or even a threat from space.

I’m not talking about aliens here. I’m talking about the possibility of the earth being struck by a meteor. And it really could happen within our lifetime. There’s something to look forward to.
This is a real threat to us and makes our petty disputes on earth seem pretty pointless and trivial.

Fairly large asteroids hit the earth on quite a regular basis. The latest one I can remember hearing about was in Russia on 15 February 2013 when an unknown object exploded high above Chelyabinsk, with 20–30 times the energy of the Hiroshima atomic bomb. Apparently it flew through the sky at 20 miles per second.

The light from the meteor was brighter than the Sun, visible up to 100 km (62 mi) away. It was observed over a wide area of the region and in neighbouring republics. Some eyewitnesses also felt intense heat from the fireball.

The danger from things like a collision with an asteroid is very real, although it might be possible to do something about it – and protect ourselves, if we manage to work together.
The following is from the PAN STARRS website – a site dedicated to observing the sky for large objects that could collide with earth. An important project!

Since it formed over 4.5 billion years ago, Earth has been hit many times by asteroids and comets whose orbits bring them into the inner solar system. These objects, collectively known as Near Earth Objects or NEOs, still pose a danger to Earth today. Depending on the size of the impacting object, such a collision can cause massive damage on local to global scales. There is no doubt that sometime in the future Earth will suffer another cosmic impact; the only question is “when?” There is strong scientific evidence that cosmic collisions have played a major role in the mass extinctions documented in Earth’s fossil record. That such cosmic collisions can still occur today was demonstrated graphically in 1994 when Comet Shoemaker-Levy 9 broke apart and 21 fragments, some as large as 2 km in diameter, crashed into the atmosphere of Jupiter. If these fragments had hit Earth instead, we would have suffered global catastrophes of the kind that inspire science fiction movies.

project.pan-starrs.ifa.hawaii.edu/public/asteroid-threat/asteroid_threat.html

General threat – I did a bit of googling.

‘There’s an asteroid with our name on it’: Brian Cox warns a space rock could wipe out humanity (if robots don’t get there first)

  • Professor Cox says we recently had a ‘near-miss’ with a large asteroid
  • No one knows when next one could be. It ‘could be tomorrow,’ says Cox
  • Engineers are working to mitigate threat, but progress has been slow
  • As well as asteroids, threats to humanity include AI and climate change
  • ‘It’s human stupidity we need to worry about,’ claims Professor Cox
  • He says threats can be prevented through research and education

www.dailymail.co.uk/sciencetech/article-2740010/There-s-asteroid-Brian-Cox-warns-space-rock-wipe-humanity-robots-don-t-first.html

So, asteroids and the asteroid threat to earth!

There are tens of thousands of objects in space that have an orbit around the sun and their orbits cross the orbit of earth. Apparently it’s only a matter of time until there’s a collision. One of these objects, a large asteroid, could collide with the earth at a massive speed. This would cause huge earthquakes and tidal waves. It would also throw massive amounts of dust, gas, molten rock and ash very high into the atmosphere – enough to envelop the entire world in burning hot ash and lava, not to mention various noxious natural gasses and possibly dangerous chemicals from the asteroid itself. The burning ash and lava would probably destroy a lot of life on the surface, like a huge explosion. But also the resulting ash and dust would probably fill the sky above earth, blocking out the rays of the sun and basically turning the whole planet into a nuclear winter wasteland. Lovely!

As far as I know, this is pretty much what happened to the dinosaurs when an asteroid hit the earth near the Gulf of Mexico a very long time ago. Apparently there may also have been volcanic eruptions at around the same time (well, about 250,000 years before the asteroid) that had already filled the atmosphere with ash and gas, making life pretty difficult already (for 250,000 years!) and then as if that wasn’t enough, a huge space rock or two smacked into the earth and that was that. The majority of life on the planet was wiped out, but not all of it of course.

We know this because the evidence is written into the earth itself. All you need to do is explore the carbon records and you can actually see the layers of different types of matter which correspond to the different events occurring, even the remains of living things, the ash, the lava rock and so on – it’s all in layers in the ground. It’s all there.

Neil DeGrasse Tyson – Death by Meteor

Neil DeGrasse Tyson talks about the real possibility of us being struck by an asteroid that scientists have been watching very carefully.

DeGrasse Tyson is one of the world’s most famous astrophysicists. He is the director of the Hayden Planetarium in New York and is generally a very media-friendly science guy who is very entertaining on all manner of scientific subjects, especially space.

Listen to DeGrasse Tyson’s predictions with some questions beforehand

Questions
Why is the asteroid called Apophis?
How do we know where Apophis is going to go?
What’s going to happen in 2029?
What are the conditions for it hitting the earth the next time it arrives?
If it does hit the earth, what exactly will happen?

Script

Death by Meteor – Neil DeGrasse Tyson

There is an asteroid, discovered in December 2004, called Apophis. Named for [after] the Egyptian god of death and darkness. It was named only after its trajectory was identified to intersect that of Earth. Had that not been the case we would not have named it Apophis. Could name it like Tiffany or something or Bambi. You know, something not threatening.

This one was headed towards Earth. Apophis.

Alright once you discover an asteroid you’ve got to wait a little while to get enough of a segment of its orbit to calculate what the full orbit will be, to know if it will come in harm’s way. So we did that… we the community… I wasn’t the one do it. We got ‘peeps’ who do this, okay?

So, ‘peeps’ if you’re over 30 means people. Okay.

Forgive me but, saying you got “peeps”, it’s people. It’s actually a loving phrase.

Right. It’s not little yellow marshmallow. (I assume they have marshmallows in USA called Peeps) Do not write.

So we get the orbit. [It] turns out in the Year 2029, the month of April, the 13th of April, a Friday. Thanks. Apophis will come so close to Earth that it will dip below our orbiting communication satellites and it is the size of the Rose Bowl. It will be the largest, closest thing we have ever observed to come by earth. Now of course a much bigger asteroid took out the dinosaurs but we weren’t around at the time so this is in the era of observing the cosmos with technology. This will be the closest biggest thing we’ll ever see come by.

Now the orbit we now have for it is uncertain enough, because these things are hard to measure and hard to get an exact distance for. The orbit is uncertain enough so we cannot tell you exactly where that trajectory will be. We know it won’t hit earth. We know it will be closer than the orbiting satellites.

There is a range – a 600-mile zone we call it the keyhole. If the asteroid goes through the middle of that keyhole it will hit the earth, thirteen years later, it will hit the earth, 500 miles, sorry 500 kilometres due west of Santa Monica.

So it doesn’t matter where it goes through that keyhole.

Now that’s if it goes through the center. If it goes through other places within that keyhole then the contact point shifts further into the Pacific or closer towards North America, yes okay.

But if it goes through the center it hits the Pacific Ocean, plunges down into the Pacific to a depth of three miles, at which point it explodes, cavitating the Pacific in a hole it’s three miles wide, three miles deep that will send a tsunami wave outward from that location that’s 50 feet high, five stories.

Oceans don’t like having holes in them, so this three mile high wall does what? [An audience member says something] You say that so timidly sir. It collapses! It’s a three mile high wall of water! Thank you, fall back into the hole sloshing against itself with such ferocity that it rises high into the atmosphere and falls back down to the ocean cavitating the ocean again.

So now you make a cavity a second time. This cycle takes about 50 seconds. You can calculate it okay? So here comes the first tsunami and 50 seconds later comes another tsunami. So there you are on the beaches of Malibu. [A] tsunami comes in. Now, unlike the tsunami in Indonesia which was one wave that went deep into the shore, this first wave needs a supply of water to exist so that the next wave actually sucks back on it to create itself. So this tsunami will only go in about a quarter of a mile. [Someone in the audience makes a noise] We have the sound effects person there [in the] upper row there.

So it only goes into quarter mile before it gets sucked back out for the next wave to come. Here’s the problem. Whatever was there on the coastline is now brought back out to sea and the next tsunami brings it back to the shore. All the million dollar homes in Malibu, they get taken out to the sea and then back. But this time they’re in a slightly different shape, okay?

And so what happens is all of them… all the artificial stuff, all the houses, the factories, they get churned into this ablative force that sandblasts the entire west coast of North America clean. So, have a nice day!

I’m sorry I said 13 years after 2020 I misspoke it’s April 13 2029 and if it threads the keyhole it will hit Earth April 13th 2036. So it’s a it’s a seven year [period].

Repeat what he said.

Highlight some of the language

Jimmy Carr talks to Prof Brian Cox about asteroids. Brian talks about Apophis

07:35

(Wikipedia)
99942 Apophis (/əˈpɒfɪs/) is a near-Earth asteroid that caused a brief period of concern in December 2004 because initial observations indicated a probability of up to 2.7% that it would hit Earth on April 13, 2029. Additional observations provided improved predictions that eliminated the possibility of an impact on Earth or the Moon in 2029. However, until 2006, a possibility remained that during the 2029 close encounter with Earth, Apophis would pass through a gravitational keyhole, a small region no more than about 0.5 miles wide, or 0.8 km[9][10] that would set up a future impact exactly seven years later on April 13, 2036. As of 2014, the diameter of Apophis is estimated to be approximately 370 metres (1,210 ft).[3] Preliminary observations by Goldstone radar in January 2013 effectively ruled out the possibility of an Earth impact by Apophis in 2036. [12] By May 6, 2013 (April 15, 2013 observation arc), the probability of an impact on April 13, 2036 had been eliminated.[3] Using observations through February 26, 2014, the odds of an impact on April 12, 2068, as calculated by the JPL Sentry risk table are 1 in 150,000.[3] As of March 2018, there were seven asteroids with a more notable cumulative Palermo Technical Impact Hazard Scale than Apophis.[13] On average, one asteroid the size of Apophis (370 metres) can be expected to impact Earth about every 80,000 years.[14]

So, Apophis isn’t going to strike the earth in 2036, thank goodness, but there’s a slim chance that it will hit the earth in 2068, but we’ll all be dead by then so who cares? (will we?)

Still, the threat remains, doesn’t it? Every 80,000 years? I think we’re probably due one again.

What can we do? Call Bruce Willis?

How NASA would deal with the problem

www.indy100.com/article/nasa-apocalypse-earth-asteroid-armageddon-plan-7826791

So, when you think about all this it makes you realise or perhaps remember that despite all our petty troubles on earth, it could all be wiped out by an unexpected collision with an asteroid. Scientists can’t always see them coming.

For me this makes me think that I should just live every day and stop sometimes to just enjoy what I have and be grateful.

So, after listening to this, take a moment to think about all the good things in your life. Even if you’re not happy these days for whatever reason. Just think about any good thing you have and think about how grateful you are for it.

Perhaps call a friend or someone you care about and tell them how you feel and say thank you for something. It might just be a good way to appreciate all of this while it lasts.