h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: The Chelyabinsk Superbolide - A87823768
Author: Galaxy Babe - eclectic editor - U128652

Hi Gnomon thanks for your assistance and suggestions

I think you need to state clearly that the superbolide was a lump of rock that was heated up by friction with the Earth's atmosphere to the point that it exploded while it was still high above the Earth. done

What altitude was it when it exploded? 23,300m (and added to the Entry)

You talk about the value of meteorites, but you don't explain what a meteorite is. I think a sentence or two at the start of the meteorite hunt section would help, for example:

A meteorite is a piece of space rock that makes it as far as the ground. When the superbolide exploded, much of it was vaporised, but hopes were high that large chunks of it might be found scattered around Chelyabinsk.added

You talk about 2012DA14 with a subscript 14, but every other report about this asteroid does not use a subscript. Can you check this, please?
That's strange because every one of my references, including the Minor Planet Centre, all use the subscript 14. However, I note that the name has changed now (!) to 367943 Duende, hardly catchy, but I've changed it nonetheless.

I think this bit could be better phrased, and could have a little extra information, too:

"Those who knew about this event breathed a huge sigh of relief. We dodged a bullet this time, as the Chelyabinsk superbolide was much smaller compared to asteroid 2012 DA14."

I suggest:
"Those who knew about this event breathed a huge sigh of relief. We dodged a bullet this time, as asteroid 2012DA14 is much bigger than the Chelyabinsk superbolide, and would do correspondingly more damage. Astronomers knew that it would not collide with the Earth this time round, but it was still good to see it receding into the distance."
changed.

Now to: You say that fragments of the meteorite were minted into medals - "minted" is normally used for making metal coins. Were the meteorite fragments made of metal? I know that some meteorites are made of metal, but you've talked about a lump of rock up to this point.

The meteorite which was put in the special medals was rock, I had assumed. But I don't know, as all my references just call it "meteorite". I saw a photo of the special medals and the meteorite wasn't "mixed" (into the metal) of the medal, but displayed in the centre, and I really can't think of a better description than "minted" - I'll give it some thought though



GB

You could say "crafted into medals".

Thank you!

GB

The only section of this I feel could be improved, now, is the last one, "Too Close for Comfort". I think all the things you present are important, but they don't quite hang together, leading to a conclusion. I've thought about this for a bit and suggest you word it as follows. Almost everything here is just re-ordering your work - I've only added a couple of sentences. See what you think:

Monitoring systems are in place to alert us to near-Earth objects. People can keep a watch for themselves on the daily-updated Spaceweather.com, which displays the Potentially Hazardous Asteroids (space rocks that come close to the Earth). At the time of writing they have logged over 1,500 PHAs, the smallest being 20m in length, the largest, 1.8km. These are the ones they know about, and none of them are on a collision course with the Earth, they're just in the vicinity.

So how much damage could one of these rocks do? The Chelyabinsk superbolide broke 100,000 windows. The Tunguska incident of 1908 knocked down 80 million trees over an area of 2,000 square kilometres. At the moment there is no technology which would enable us to protect our planet from an asteroid hit, even if we knew about it in advance. All we could do is evacuate the projected strike area, if the authorities had enough warning. Unfortunately, we might not get much notice. On New Year's Day 2014, an asteroid, 2014 AA, was discovered by the Mount Lemmon Survey (whose job it is to detect NEOs). The following day it entered the Earth's atmosphere and what remained plunged into the ocean somewhere between West Africa and Central America. Thankfully the asteroid was only 3-4m in diameter.

Many people believe that the extinction of the dinosaurs might have been caused by a strike by a really big asteroid at Yucatan, Mexico, although we can't know for sure. The effect of such a collision would be a catastrophe affecting the whole world. There are many Near Earth Objects out there. We can only hope one of the biggies doesn't have our planet's name on it.

Thanks very much Gnomon, I've amended the Entry to your suggestions

Just by the way... That largest PHA I mention in the Entry? It passes Earth today...

GB

That's the 1.8km one? indeed!

Yes, glad to see the back of that one!

Anything else?

GB

Just two things:

a semicolon rather than a comma after kilotons

I don't like the sentence that starts "Those who had the ability..." it sounds dull and pedestrian compared with the rest of the entry. You could say "Those with the technical savvy..." or something like that.

Other than that, this is ready for picking.

many thanks

GB

Your Guide Entry has just been picked from Peer Review by one of our Scouts, and is now heading off into the Editorial Process, which ends with publication in the Edited Guide. We've moved this Review Conversation out of Peer Review and to the entry itself.

If you'd like to know what happens now, check out the page on 'What Happens after your Entry has been Recommended?' at EditedGuide-Process. We hope this explains everything.

Thanks for contributing to the Edited Guide!

Explosive stuff I look forward to seeing on the Front Page!

<BB<

Well done!

Congratulations!

Thank you very much

GB