Meteor madness 2 – look at the size of that thing

So yesterday was all abuzz with cool videos of the Chelyabinsk meteor, and a whole bunch of questions.  How big was it? Did any of it hit the ground? Did it explode or not? How fast was it going?

Today we start to get some refinement on the preliminary answers.  Most startling of all of these are the size estimates.  The original numbers given by the Russian Academy of Sciences were that it was about 2 cubic meters, and 10 tons.  That was handily blown out of the water by estimates made from infrasound stations, which put the numbers at 15 m  diameter (~1700 cubic meters) and 7000 tons.

This morning that number has been further increased to 17 m diameter and 10,000 tons.  This thing was approaching the atmosphere at 18 km per second, and is estimated to have released 500 kt TNT equivalent of energy during the event, over a period of 32.5 seconds. To put that energy in context, the “Little Boy” bomb dropped on Hiroshima at the closing of World War 2 had a yield of approximately 16 kt. So, assuming it was shedding energy at a constant rate (which it wasn’t) it is almost exactly the equivalent of a Little Boy detonation for every second it was in the atmosphere. For a while this thing was glowing brighter than the sun.

Witness photo of 2013 Russian meteor event made ​​from Chelyabimsk Drama Theatre, Nikita Plekhanov

Witness photo of 2013 Russian meteor event made ​​from Chelyabimsk Drama Theatre, Nikita Plekhanov

So, It entered the atmosphere, created an airburst at between 30-50 km altitude, and is known to have hit land in at least three places – two near Chebarkul lake (an impressive picture of the hole left by one of them is available here), and another 80 km away near the town of Zlatoust. There’s reports of another couple of pieces that may have come down in Khazakstan as well.

Looking forward to seeing what comes of any samples they recover, which will tell us what kind of meteorite it is, and will probably lead to some recalculation of the numbers given so far.

In the mean time DA14 passed – as expected – without incident.

I’ll leave you with a pretty incredible animation that puts the spotting of these smaller asteroids in some perspective.  This demonstrates the history of asteroid spotting over the last 30 years far better than any plain description can.  What else is out there?

Posted in Astronomy, Geology, Hazard Assessment, News, Physics, Science | Tagged , , , , , , , , , , | 1 Comment

Meteorite madness

hot-hail-300-75

[Updated 11.00 am CET]

[Update 2 13:40 CET - impact crater located and reported at 6m diameter]

[Update 3 20.00 CET - massive revision on the meteorite size. Early estimates of 2 cubic meters and 10 tons, increased by 3 orders of magnitude to 700 tons and over 3000 cubic meters (15 m) wide]

 

[UPDATE 4 - 16th Feb. Size revised upward again - see here for more info]

I was looking forward to seeing what exciting meteorite news today would bring. Far from precognition, I was anticipating the rather close flyby of asteroid DA14, which in a little under 12 hours is due to pass about 34,000 km over our heads.  While the ISS orbits at a piddly 300-400 kilometers, 34,000 km puts DA14 inside the orbit of our geosynchronous satellites.

Little did I realise that I was going to wake up to the altogether more spectacular footage emerging from Russia this morning. At about 9.00 am local time an asteroid plunged into the atmosphere over the Chelyabinsk region of Russia.  This was particularly good for several reasons. Firstly, it’s a time in the morning when there’s plenty of people around to see it, secondly, it was a beautiful crisp clear winters morning, and thirdly because it was in Russia, and the Russians love to have cameras on their car dashboards. Who knew corruption and scamming could have scientific benefits?

The result is videos like this:

and this

To have any footage at all of these events is unusual and useful. To have so much footage from so many different angles and perspectives is really quite incredible. There’s a good repository of some of the best clips here from Emily Lakdawalla

http://www.planetary.org/blogs/emily-lakdawalla/2013/02142336-breaking-meteor-fall-causes.html

The obvious question which starts cropping up is whether this meteor is related to the DA14 event.  That question I think has been adequately dealt with – at elast based on preliminary data – by Phil Plait (@BadAstronomer) who summarises that

“I do not think this is related in any way to the asteroid 2102 DA14! For one thing, this occurred about 16 hours before DA14 passes. At 8 kilometers per second that’s nearly half a million kilometers away from DA14. That puts it on a totally different orbit.”

and furthermore

“from the lighting, time of day, and videos showing the rising Sun, it looks like this was moving mostly east-to-west. I may be off, but that’s how it looks. DA14 is approaching Earth from the south, so any fragment of that rock would also appear to move south-to-north.”

I strongly recommend you read his post in full, as it also encompasses some great images.

The information coming out of Russia has been somewhat confused.  Initial claims even suggested the military had shot the meteorite down – a somewhat outlandish claim.  Injury estimates were ranging anything between 0 – 100, although the Russian Interior Ministery has since updated the numbers to over 400 people seeking medical attention. These were mostly due to broken glass, caused by the enormous sonic boom as the meteor passed overhead.

UPDATE: Meteosat caught the moment the asteroid started entering the atmosphere

There’s a massive thread on r/AskScience at Reddit that I’ve been looking after for the last few hours that’s worth checking out.

Here’s some more link and video repositories you might like to have a browse through.

http://gawker.com/5984470/apparent-meteorite-crash-in-russia-causes-giant-explosions-forces-evacuation-of-nearby-offices-and-schools

http://www.russianmachineneverbreaks.com/2013/02/14/what-is-happening-in-chelyabinsk/

Posted in Astronomy, General, Geology, News, Science | Tagged , , , , , , , , , | 3 Comments

When Twitter goes bad…

Very very short post for no other reason than this amused me and I thought some others might like it. Every few days Twitter sends an update suggesting people to follow based on who you already follow. So if you follow, say, BBC News, they might suggest you follow the Associated Press.

Among many other things, I follow the very amusing Drunk Hulk. This is the recommendation email I just received:

Hulk deGrasse Tyson

 

I can only assume he has some off days?

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The experimentalist

I got asked a question the other day, and it got me thinking. The question was ‘what makes a good scientist?’

The more I thought about it, the more I realised that while there are a number of key traits that I considered central (‘lateral thinking’, ‘good communication skills’, ‘self motivated’), I could think of well regarded professional researchers who were exceptions to each of them. The only skill I have been able to settle on so far as being universal is the ability to critically think.

There are scientists who are team players, and those who are better working alone (for their own, but often also their colleagues sanity). There are plenty of careful scientists with a precise and measured approach to everything. There are also many I’ve come across who are often a little more slap-dash and clumsy, but who churn out excellent science nonetheless.

I also don’t think research scientists are more intelligent than the general population. We’ve been trained to look at problems and think in a certain way, and we draw on a lot of experience and education, but given those factors I think most people could do what we do.  There’s nothing in our skillset and abilities that can’t be taught.

It was then I realised what the other common factor is to every professional science researcher I know. A love of the science.

Pay and conditions for researchers aren’t that great. While you’re still in school, the people who started work at 16 will have 10 years of earning and promotion behind them, while you’ve been racking up debt. The PhD process is well known as a tough slog, and you then begin hearing rumours that there are far more PhDs being produced than there are available jobs. If you get lucky you then start a career at a moderate level of renumeration, but requiring years in short term contracts which often mean migrating nationally or internationally.

Despite all that, most postdocs I know love their jobs. Sure, they get pissed off at the moving and instability and the general climate of work, but they still love their jobs because they love doing the science.

There are plenty of people who get their PhDs and have the love of science beaten out of them by the time they finish. Or at least that love is overwhelmed by other needs or desires. And there seems to be a reasonable amount of work available for those people. In fact, these other jobs also tend to get paid a hell of a lot more than those in research. Which again highlights that those who stay in it are generally there for the love of carrying out cutting edge science.

In my quest to give a more comprehensive answer to the question I’d been posed I decided to try and concentrate more specifically on my own type of work – that of experimental science.

Here it is more specifically important to maintain a methodical approach. But I find an almost playful inquisitiveness is also really important.  Just this afternoon I was having a conversation with a colleague about the benefits of spending some time just messing around with the equipment and materials you have available to see what interesting behaviours and features can be encountered. In fact, an interesting point came up when my colleague explained that next week he is going to be letting some Masters students loose on trying to model debris flows. He made the excellent point that quite often what they do is crazy and illogical, as they do not have the base of experience to know what *should* happen. But we also agreed this can be a fantastic boon, as they have none of the preconceived notions of how a particular method should be carried out. So while there can be a lot of ‘failed’ experiments, and they learn a lot of lessons about why certain things are done certain ways, both of us fully intend to go and see what they attempt and see if we can’t learn a few things ourselves about what features and flow processes might be investigated with a little bit of a leftfield and original method.

So what traits are essential to your field?

I’ll leave you with a video I put together today showing what happens when you pass gas through a powder material at such a high rate that the material passes through ‘fluidised’ and comes out the other side as bubbling. Stress chains within the material allow conduits to form. I’ve seen it described in many papers, but it’s the first time I’ve played with the mechanism myself, and took the opportunity to use the high speed camera to record it. I think it’s pretty neat – you can see the discrete gas bubbles pass up the sidewall. It was shot at 1000 fps and plays back at about 1/15 speed (30 seconds of video is 2 seconds of footage – timestamp is in the top right). There’s a 2cm grid on the right for scale. For some reason I can’t link to the HD version, so make sure you select the HD option on playback.

Posted in Experimental, General, Geology, Physics, Science, Sedimentology, Volcanism | Tagged , , , , , | Leave a comment

Measure twice, cut once.

My dad was a design and technology teacher. I was exposed to the arts of woodwork, construction, design and so on as a child, and – while my brother went off and became an engineer – I have to say I’ve not particularly made use of those skills since I was doing my GCSEs. That said, I always enjoyed technical drawing, the precision and 3D spatial planning (and indeed, that same 3D spatial awareness that is so important in many aspects of geology).

While I was doing my PhD and had to design some flume equipment I had a flash of interaction with things again, but it was an absurdly simple three-part flume that a 7 year old could have designed and assembled.  For this current project, however, somewhat more time and effort has had to go into flume design. In fact, the full first month was spent doing little but designing and refining the flume, to ensure it was capable of producing the results I want to achieve without being blown apart by high pressure gases or collapsing under its own weight.

So I found myself with a ruler and protractor drafting out isometric sketches and trying to make sure everything fitted together. Then a stroke of genius hit and I booted up Google Sketchup. I’d used it a few times before, but I reasoned that while I could sketch by hand as much as I wanted, by producing a 3D model I would ensure that all the separate parts would fit nicely, and I could read the numbers for part ordering straight out of the model.

Sketchup models of some flume parts.

And I was right – in fact, it was even quicker than drafting by hand. A couple of people in the lab were quite impressed by these models I was producing and got interested.  I took images of the models down to our outstanding workshop engineer, and he was very pleased with the detail – illustrations of where cutouts needed to be made, clear ideas of where we would need PVC, where we would need aluminium, where perspex, and even where particular joins should be made (and how).  It enabled me to design the somewhat complicated hopper shape (do a Google search for ‘hopper geometry’ and you’ll quickly realise that simply whacking a great big box on top of a release mechanism is not the done thing), and was even able to ensure it would be of a certain volume and mass.

So I was ever so pleased with myself when the purchase order went off with all the outputted measurements for the 75 or so separately cut pieces of material, in a variety of materials and thicknesses.

I was less pleased this morning after an hour in the workshops ensuring that all the pieces fitted together nicely to discover that the 3000 mm x 100 mm x 10 mm  perspex flume base had been delivered at 3000 mm x 130 mm x 10 mm. Sounds trivial, but Perspex is really horrible to cut, even in a well equipped workshop. A 3 m length of it is unwieldy and impossible to deal with without some very specialist equipment.

I checked the purchase order. 3000 x 130 x 10. Bugger. How did they make that mistake. Why did I not notice it? I spent some time cursing myself for not checking the purchase order more carefully. I went and double checked again. Then I went and looked at the original paperwork. The spreadsheet I had specced everything on was correct. Then I checked the order email. I’d sent.  Hmm. That was wrong.

So, what had gone wrong? Idiot cut and pasting. I had copied the details from one part, and pasted them, then pasted the same values for the next part on the list.

In summary, after a morning of ferrying a 3m length of perspex to and fro between the suppliers and their enormous cutting machine to remove 30 mm of excess plastic, I propose a 21st century modification to the age-old adage ‘Measure twice, cut once':

“Measure twice, cut once, paste once, check”.

At least it was cut too big rather than too small – that would have been both annoying and expensive.

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Tongariro Fireworks

Following the little spike of activity back in August, Tongariro in New Zealand reactivated today with a 5 minute explosive eruption jetting up a small plume and generating some very limited pyroclastic flows. With it being a daytime eruption, and with New Zealand getting firmly into its summer season there were, inevitably, a number of people attempting the Tongariro Crossing – a very popular hike that snakes past the dramatic Mt Ngaruhoe and up onto the nested craters of Tongariro proper.

Among this group of walkers was a pro film crew.  The net result is that some truly spectacular video got captured of the plume immediately after eruption, and showing some of the small PDCs generated from it. I strongly recommend going to have a look here. Not only do you get the joys of some lovely volcanology, but the added bonus of a soundtrack of overexcited and dramatically screaming children.

The volcano is at Alert Level 2 and Aviation Colour Code Orange.

EDIT: Here’s the seismics from Geonet for the last 24 hours. You can see the observed eruption a little before the 10 hour line (the drums are marked in hours before present, with present being about midnight New Zealand time, and the eruption going off at about 1.30 pm local time).  It looks like there’s possibly been a further pulse of activity just over 2 hours ago.

EDIT 2: Quick and dirty compilation of the webcam images from Geonet / GNS Science, showing a lot of geothermal outgassing activity before and after the eruption. Available on YouTube here.

I’ll update as and when I get a bit more info.

Posted in Education, Geology, Hazard Assessment, News, Science, Volcanism | Tagged , , , , , , , , , | 1 Comment

Accretionary Wedge #52

Been a while since I had a chance to get in on the Accretionary Wedge, which – for those of you who are perhaps not familiar – is something of a geoscience blog carnival. Once a month, someone hosts a new topic for the rest of us geobloggers to wax lyrical about.  This month Vi-Carius is hosting, with a topic broadly about ‘geoscience courses you wish existed’

Now, it’s been a while since I was an undergraduate. In fact, I was away from geoscience for several years before coming back to do my PhD.  And that’s really where my dream course would have fitted in.

Rather than Geoscience 101, I’m thinking more a ‘Geoscience 999′. A short sharp kick-up-the-rocks for people who could do with a refresher. Maybe 5 or 6 hours of lectures, one each recapping the key details (and last 10 years developments in) each of half a dozen key subject (plate tectonics, palaeo, geochem, geophys, sedimetology and volcanology?). Broad strokes coverage, with updates of key concepts where necessary, each followed by 3-4 hours practical work getting back up to speed with stuff like microscopy, map drawing, strat logging, etc. That would really have made my life easier.

That said, I can understand that actually it’s only marginally useful for a lot of people. So that gets me wondering what would be most useful for the most people. And by most people, I’m extending the remit slightly to mean everyone. Not just geologists. Not even just university students. The whole bloody lot of you. The answer I have come to is informed by the experience I’ve had teaching, lecturing and demonstrating, and remembering one of the most useful lectures I’ve ever had.

That lecture was given by Dave Waltham – who ended up as my future PhD and eventual postdoc supervisor. His qualifications are in Physics, but he has diligently spent most of his career at the Earth Sciences department at Royal Holloway  University of London ensuring – among many other things – that there was a friendly face and a clear explanation awaiting any geologist who was at a mathematical or conceptual roadblock.

And the lecture was this: Ballparking. At its simplest, how to calculate a rough first-order approximation for any given calculation.  As professional researchers I think it is something that we get good at doing, and the ability to quickly estimate whether something is ‘about right’ or not is phenomenally useful in a vast array of situations. Eyeballing a recipe when you’ve only got 2 eggs instead of 3? Ballpark it. Trying to calculate how to split a restaurant bill? Ballpark it. Trying to work out how many cricket balls you can fit in a stadium?…. You get the idea.

The interesting thing is that it is a skill that I certainly find is absolutely lacking in many people. Knowing how to simplify what would otherwise be a complex calculation into a first-order accurate approximation you can do in your head – or at least in 20 seconds on the back of an envelope – is something that everyone would benefit from. Imagine the time that could be saved!  Everything from working out whether a cheap but high mpg car is better value than expensive low mpg one, to arguing about how many whales you could fit in the oceans.

Ballparking is not necessarily an intuitive skill, and there’s plenty of shortcuts and tricks that a taught course should pass on. When you can and can’t round numbers, and by how much, what are reasonable simplifications, and which are not. Giving everybody the confidence to look at a number presented to them in context and the ability to judge whether the data are good would – I think – be a huge boon to society.

So that’s my wish. Quick and dirty maths for the masses.

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