Archive for category It’s the end of the world as we know it

Another day, another stupid asteroid scare

The road I live on has a railway running across the end of it. Every day, hundreds of tons of metal speeds along the line just a hundred metres or so from my house. Yet I don’t live in fear of waking up one morning and finding a train’s crashed into my house, because of course the trains are restricted to the railway tracks.

Space is much the same. Asteroids are whizzing around over our heads every day, but they follow precisely defined orbits through the sky. An asteroid passing close to the Earth is no more a “near miss” than a train passing my house without hitting it is a “lucky escape”.

It’s a simple enough idea, you’d think, and yet…

“Phew, that was a near miss: Cigar-shaped asteroid stronger than ’15 atomic bombs’ whizzes by earth”

Thankfully, the 50m long rock that could have destroyed a small country went barely noticed as it passed earth at a distance of some 2,085,321 miles.

Yes, the asteroid 2011 GP59 could have destroyed a small country. If it was two million miles closer.

Once again, this article has been taken from the Australian news site news.com.au, who seem to have a thing for scaremongering stories about space; they also started the rumour that Betelgeuese would go supernova in 2012 and gave credence to the shameful “supermoon” story. At least the Mail‘s headline is less awful than news.com.au’s, who’ve gone with “Scientists find asteroid with potential power of 15 atomic bombs. Heading this way. Tonight.” which surely has to rival shouting “fire” in a crowded theatre in terms of unethical scaremongering stupidity.

Incidentally, the claim that it’s “as powerful as 15 atomic bombs” doesn’t come from any scientific authority. It comes from the news.com.au journalist – who doesn’t appear to be a science journalist at all, but a technology journalist – digging up an old New Scientist article about an asteroid that exploded with the energy of three nuclear bombs (three of the very small Hiroshima bombs, I should point out, not a modern nuclear bomb), and then scaling it up. This is a stupid calculation for a number of reasons:

  1. You can’t just say “this asteroid is 10 metres long, this asteroid is 50 metres long, therefore it’s 5 times bigger”. It’s the volume which is important – the length times the width times the height. Assuming the asteroid is 5 times bigger in each direction, then it’s 5 x 5 x 5 times bigger, which is 125 times the size. If the journalist hadn’t cocked up his maths, he could have made this asteroid sound EVEN SCARIER. Except…
  2. The amount of energy an asteroid has depends on its speed. A fast moving asteroid carries far more energy than a slow moving one, and a small increase in speed causes a much larger increase in energy.** The gravitational pull of the Earth as the asteroid approaches plays a large role in determining its speed, so the energy it would have would depend on the route it took to Earth. Since this asteroid is not heading for Earth, it’s meaningless to ask how much energy it would have if it hit Earth.
  3. It also depends what the asteroid is made of. Most asteroids are made of dust and ice, and burn up harmlessly in the atmosphere. A few – maybe one per year – explode high up in the atmosphere. And a very, very few – mostly large metallic asteroids that don’t burn as well –  hit the ground. Again, we don’t know what this asteroid is made of.
  4. THE ASTEROID IS TWO MILLION MILES AWAY AND WILL NOT HIT EARTH AT ANY TIME IN THE FORESEEABLE FUTURE.

At any rate, there are literally thousands of asteroids this big – or indeed much bigger – rattling around near-Earth space, and there must be thousands more we haven’t detected yet. It’s worth being sensibly worried about the risk of currently undiscovered asteroid hitting us, but getting worked up about an asteroid that we know can’t hit us is just stupid.

Now, if you’ll excuse me, I’m off to dig a train-proof bunker in my garden.

* Psst, Daily Mail Reporter. “Earth” has a capital “e”.

** In fact, energy is proportional to speed squared – if you double your speed, your energy goes up fourfold.

,

1 Comment

Radiation scaremongering in the Daily Express

On March 30, The Daily Express ran with this front page this front page article:

TSUNAMI NUCLEAR FALLOUT HITS UK

The headline’s technically true, but the scale of the radioactive fallout compared to the media fallout is a bit out of sync. Slightly elevated levels of the radioactive isotope iodine-131 (I-131) have been seen in Glasgow and Oxfordshire, but the key word here is slightly.

The levels of I-131 detected in Oxfordshire rose by 0.0003 becquerel per cubic metre (Bq/m3), while in Glasgow it rose by just 0.00001 Bq/m3. A becquerel (Bq) is the unit of radioactivity; 1 Bq means you have one radioactive atom decaying and releasing radiation per second. These decays are what produce the distinctive clicks of a Geiger counter; each “click” represents a flash of radiation from the decay of one atom. As you may have seen in school, even when held away from radioactive sources a Geiger counter will probably give you a click or two per second – we’re surrounded natural radiation from the air, the ground, space and even from our own bodies. Around you right now, radon gas is releasing, on average, 20 Bq/m3 of radiation while inside your body, radioactive potassium-40 is decaying at over 4,000 Bq, and carbon-14 is producing radiation at a similar rate. Compared this background radiation, the change due to fallout is minimal: 0.0003 Bq is equivalent to one atom of radioactive iodine decaying per hour, and 0.00001 Bq is one extra decay per day. (For some perspective, after Chernobyl I-131 levels in the air at Harwell reached a maximum of 4 Bq/m3, ten thousand times the levels seen in Oxfordshire.)

Working out how much harm radiation causes isn’t always easy – a few bequerels from radon gas are more harmful than the thousands of bequerels released by potassium in your body, since radon releases harmful alpha radiation instead of the comparatively safe gamma radiation, and radon spends most of its time lurking in your delicate lungs – so to work out the risk you need to work out the equivalent dose, a measure of how much damage the radiation does to the body usually measured in sieverts. Being exposed to 0.0003 Bq/m3 extra I-131 is equivalent to an increased dose of 0.01 microsieverts (μSv) per year. You would absorb almost as much radiation just by sleeping next to someone for one night. For comparison, the smallest dose that we know to be harmful is around 100,000 microsieverts per year; millions of times more than anyone in the UK could receive from the fallout.

The Express quotes John Large, one of the critics of the nuclear industry, as saying:

The International Commission on Radiological Protection – which is made up of government agencies – is quite clear. It says any increase in accumulated radiation dose exposure is accompanied by a proportionate increase in risk. That is the natural law.

For Sepa [Scottish Environmental Protection Agency] to make profound statements about it is ‘not of concern’ to the public is not right. Of course the risk’s tiny but it’s up to the public to decide.

If you want the public to make an informed decision about nuclear power, it has to actually be informed. Screaming about “TSUNAMI NUCLEAR FALLOUT” without providing any context is not helpful, it’s just scaremongering, plain and simple.

Since the harmful dose for radiation is 5 million times higher than the levels found in Oxfordshire, I wonder what John Large would like Sepa to have said. Saying that these radiation levels are not of concern is not leading the public on, it’s simply a cold, hard medical fact. If Large does think these radiation levels are of concern, then may I suggest that his next statement focuses on the extreme dangers of radioactive bedmates.

1 Comment

The Supermoon did NOT cause the earthquake

Normally, scientists are meant to be circumspect and reserved about cause and effect. We’re supposed to deal in probabilities, statistics and uncertainties. However, on this occasion, I have absolutely no qualms in saying this: The Daily Mail is wrong. The “Supermoon” had nothing to do with the terrible earthquake off the coast of Japan today.

Ben Goldacre and Phil Plait have already produced some admirable rebuttals to the Mail‘s exploitative scaremongering; these are my thoughts, but I recommend reading the linked posts.

The powerful tsunami that today slammed into Japan’s eastern coast comes just two days after warnings that the movement of the moon could trigger unpredictable events on Earth.

Except none of these “warnings” come from scientists. The only people who took the “Supermoon” seriously were internet conspiracy theorists and the tabloids. And…

Astrologers predicted that on March 19 – a week tomorrow – the so-called ‘supermoon’ will be closer to Earth than at any time since 1992, just 221,567 miles away, and that its gravitational pull will bring chaos to Earth.

An astrologer is the not same thing as an astronomer. A warning from an astronomer should (generally) be taken seriously. A warning from an astrologer isn’t worth the paper it’s printed on.

Others on the Internet have predicted it will cause further catastrophes such as volcanic eruptions and earthquakes.

“Others on the Internet”? Of course, everything that was ever written on the internet MUST be true.*

* Fully aware of the hypocrisy, thank you very much.

However the ‘supermoon’ date is still eight days away. But those that adhere to this particular belief could claim that this was still close enough for there to be some kind of effect.

Ok, as everyone knows, the moon orbits once a month. Once every two weeks, it comes close to the Earth – this is the “perigee” of its orbit – and in between these perigees we have the furthest points: the “apogee”. This means that eight days before the perigee, it will be as far away as possible from the Earth; the exact opposite of a “supermoon”. Its gravity would be weaker, not stronger.

The energy needed to produce an earthquake builds slowly through stress and strain in the rocks where tectonic plates meet, over years or decades. A tiny change in the position of the moon – a change which, remember, happens twice a month – will have virtually no effect compared the constant force of billions of tons of rock pressing against each other.

Two days ago, in an interview with ABC radio discussing the potential impact of the March 19 supermoon, astrologer Richard Nolle, who first coined the term in 1979, said he was convinced that lunar perigees cause natural disasters on Earth.

‘Supermoons have a historical association with strong storms, very high tides, extreme tides and also earthquakes,’ he said.

The only one of those that is true is that “Supermoons” can cause high tides (and even then, it only changes the tidal range by a couple of percent). There is no association between “Supermoons” and storms or major earthquakes. And again, an astrologer is NOT an astronomer.

Natural disasters are unfortunately common. Earthquakes, storms and floods happen with depressing regularity – look hard enough and you can find disasters happening around any supermoon. What’s important is to the look at the disasters that weren’t linked to a supermoon. No scientific study has shown an increase in quakes or storms around supermoons.

What do the actual scientists say?

Dr David Harland, space historian and author, said: ‘It’s possible that the moon may be a kilometre or two closer to Earth than normal at a perigee, but it’s an utterly insignificant event.’

Professor George Helffrich, a seismologist at the University of Bristol was equally dismissive.

‘Complete nonsense. The moon has no significant effect on earthquake triggering.

‘If the moon triggers “big” earthquakes, it would trigger the many of millions of times more “small” earthquakes that happen daily. There is no time dependence of those; hence no moon effect.’

[...]

John S Whalley, geoscience programme manager at the University of Portsmouth, agreed there was no correlation.

‘There is no established correlation between variations in the orbit of the moon and either the number or magnitude of earthquakes.

‘It is all too easy, with hindsight, to link major earthquakes to variations in all sort of parameters.

‘The real test is to look at the vast numbers of earthquakes of all magnitudes that occur on a daily basis worldwide.

‘Any correlation with the lunar orbit would have to be established on the basis of this population of earthquakes, not on individual high magnitude events. In need hardly add that no such correlation has been established.’

I would end this post with another glib link to the SMBC comic, but frankly I don’t feel like this the right time for daft jokes. Nor is it the appropriate time for a newspaper with a readership of millions to be giving a platform to charlatans and conspiracy theorists, who seize on a terrible tragedy just to get a little bit of publicity for their pseudoscientific claims.

,

4 Comments

Supermoon!

The moon from Majora's Mask

You've met with a terrible fate, haven't you?

The question: Could ‘supermoon’ next week disrupt Earth’s weather?

The web was yesterday awash with apocalyptic warnings that the movement of the moon will trigger tidal waves, volcanic eruptions and even earthquakes next week.

The conspiracy theorists claim that on March 19, the moon will be closer to Earth than at any time since 1992 – just 221,567 miles away – and that its gravitational pull will bring chaos to Earth.

The answer:

But astronomers have dismissed the claims as pure nonsense.

Take us away, Saturday Morning Breakfast Cereal.

Edit:

The Sun and Metro have both managed to be much worse than the Mail. The Sun has the headline “‘Disaster’ as Moon closes in” while Metro has “‘Supermoon’ may cause weather chaos for coastal Britain“. Bear in mind that the Moon comes almost this close twice a month – the only thing that makes this time “super” is that it happens to coincide with a full moon, and even then, that happens every 2 or 3 years. This will cause slightly higher tides, yes, but according to the NOAA, these happen 3 or 4 times per year (since they can be triggered by new moons and nearly-full moons too) and the change in the tide is only around 2%.

The Telegraph‘s coverage is better – there’s far less doom – though as much as I hate to be a party pooper, it’s going to be less dramatic than they make out. On average. the moon’s “angular diameter” – the amount of the sky it fills up – is 0.259 degrees. In other words, the moon would appear the same size as a five pence coin held 1.99 metres (6 feet 6 inches) away from your face. During the supermoon, its angular diameter is 0.274 degrees- the same as a five pence coin held 1.88 metres (6 feet 2 inches) away. That’s roughly a 6% increase in size – and this increase happens twice every month.

If you could compare the two side by side, you would see the difference – if you’ve got a small telescope or a decent pair of binoculars, then a supermoon should be a great opportunity to have a look up there – but otherwise, you probably couldn’t tell (the moon illusion causes the size of the moon to appear to vary by way more than 6% anyway). At any rate, the Telegraph‘s illustration is… a little exaggerated.

, , , ,

5 Comments

Asteroid, doom, whatever, yawn

Devastating asteroid impacts are thankfully incredibly rare, with millions of years between impacts. One thing that’s not rare is the killer asteroid scare story.

Today’s Mail claims ‘Doomsday’ asteroid could slam into the Earth on April 13, 2036… but don’t worry, we’ll have seven years’ warning, ominously following that with “Warning comes days after another asteroid shot over the Pacific just 3,400 miles above the Earth’s surface

First of all, the asteroid that shot “just” 3,400 miles over the Pacific? That was Asteroid 2011 CQ1, and it was about the size of a washing machine. That’s not dangerous. At all. According to NASA, “there is likely to be nearly a billion objects of this size and larger in near-Earth space and one would expect one to strike Earth’s atmosphere every few weeks on average“. Far from being dangerously close, this asteroid was unusual in that it didn’t quite hit us – if it had, it would have burnt up harmlessly in the atmosphere and no-one bar a few astronomers would have noticed.

Anyway, the “”doomsday” asteroid” in question is Apophis, a name you’ll probably recognise from previous media frenzies in 2009, 2008, 2007 and 2005. Nothing has changed since then; in fact, the odds of collision are gradually getting longer (its position on the danger scale has dropped from 4 – a 1% chance of dangerous impact – to zero). We’ve got a fairly good idea of what the asteroid’s path looks like, but there’s a tiny bit of uncertainty we’ve still not cleared up and it’s possible that it might be on a path that will eventually hit Earth. Luckily for us, the odds that it’s on that path are just 1-in-250,000 (your odds of being killed by Apophis are roughly the same as the odds of being killed by rats or cave-in, apparently). We’re talking lottery odds here.

For a more detailed analysis, there’s a great post at Bad Astronomy – Repeat after me: Apophis is not a danger!

As Nick Ross used to say, don’t have nightmares.

Leave a comment

Sham painful supernova

Everyone knows the old Mark Twain quote, “A lie can travel halfway around the world while the truth is putting on its shoes“. Today we have a weirdly literal example of that.

A couple of days ago, the Australian news site news.com.au ran a story which claimed that the star Betelgeuse was going to go supernova in 2012, that its explosion would light up the sky, that it would burn so brightly that we’d have two suns, and that the explosion would tie in with the old 2012 Mayan prophecy BS.

Pretty quickly, astronomers like Phil Plait and Ian O’Neill wrote responses to the article, pointing out that while an exploding Betelgeuse would be spectacular, it would still be less bright than the moon (so no two suns), it would be too far away to have any effect on the planet, and we have no way of knowing whether Betelgeuse would explode tomorrow or in a million years.

Guess which line the British papers have gone for?

The Daily Mail runs with Earth ‘to get second sun’ as supernova turns night into day, complete with a still from Star Wars (because that’s a movie that had two suns in it!) while The Telegraph has ‘Second sun’ on its way. Both claim that “scientists” have predicted the 2012 supernova, but as far as I can tell, no-one’s done any such thing. The scientist quoted by news.com.au actually just made perfectly sensible comments about what supernovae are – the only connection to 2012 is randomly thrown in by the journalist who wrote the piece, Claire Connelly.

For a full debunking, either of the blogposts linked above is worth reading, as is news.com.au’s own apologetic follow-up, Betelgeuse ‘not likely to explode in 2012′.

Of course, it won’t be long before this story – devoid of context and rebuttals – gets pride of place on 2012 conspiracy sites, and then the whole vicious cycle will begin again.

,

2 Comments

Follow

Get every new post delivered to your Inbox.

Join 487 other followers

%d bloggers like this: