Solved: riddle of Siberia's flattened forest

A century on, scientists say massive explosion was caused by comet collision

A massive explosion that flattened an entire forest in northern Russia over an area of 800 square miles more than a century ago was almost certainly caused by the Earth colliding with a comet, according to a study by rocket scientists in the United States.

The explosion in 1908 occurred in the sky at a remote location in Siberia near the Tunguska river. It is estimated to have been equivalent to a 20-megaton nuclear bomb, which would have decimated everything within the M25 had it occurred over London rather than a largely uninhabited region.

Tunguska has long been the subject of intense speculation, with suggested causes ranging from the release of a gigantic cloud of explosive methane gas from underground, to a collision with anti-matter particles from deep space, or even the crash of a visiting extra-terrestrial spacecraft.

One of the most likely explanations, however, had been that the Earth was hit by a piece of space rock – but a number of scientific expeditions to the area failed to find the impact crater, suggesting that if such a meteoroid had struck the Earth in 1908 it must have exploded high enough in the atmosphere to have disintegrated before reaching the ground.

Now a team of researchers studying the plumes of water vapour created by the rocket engines of the Space Shuttle believe they have found the crucial evidence in favour of another theory: a collision with the icy heart of a comet.

This would have released huge volumes of water vapour at very high altitude, creating highly reflective clouds that may explain why the sky was lit up for days after the collision, with people as far away as London saying that they could read newspapers outdoors at midnight, the scientists said.

"It's almost like putting together a 100-year-old murder mystery," said Michael Kelley professor of engineering at Cornell University in New York. "The evidence is pretty strong that the Earth was hit by a comet in 1908."

The dramatic illumination of the night sky in the day after the event on 30 June 1908 was probably caused by the formation of "noctilucent" clouds – named because they are visible at night – which are made up of ice particles formed at very high altitude and low temperatures, Professor Kelley said.

A study of exhaust plumes from the Space Shuttle have shown how noctilucent clouds can form a day after a shuttle launch and many miles from its flight path due to high-speed winds generated at this altitude, the scientists found. The exhaust plume is a model of how a comet would have created similar noctilucent clouds, they said.

The appearance of skies bright enough to read newspapers at night as far away as London – some 3,000 miles away from Tunguska – could be explained by the transport of huge volumes of water vapour arising from the comet by the high winds of the upper atmosphere where these clouds form, Professor Kelley said.

Arts and Entertainment
books
News
Dr Alice Roberts in front of a
people
Voices
Nigel Farage arrives for a hustings event at The Oddfellows Hall in Ramsgate on Tuesday
voicesA defection that shows who has the most to fear from the rise of Ukip
Arts and Entertainment
The Doctor and the Dalek meet
tvReview: Doctor Who Into the Dalek more than compensated for last week's nonsensical offering
PROMOTED VIDEO
Sport
Diego Costa
footballEverton 3 Chelsea 6: Diego Costa double has manager purring
Arts and Entertainment
The 'three chords and the truth gal' performing at the Cornbury Music Festival, Oxford, earlier this summer
music... so how did she become country music's hottest new star?
Life and Style
The spy mistress-general: A lecturer in nutritional therapy in her modern life, Heather Rosa favours a Byzantine look topped off with a squid and a schooner
fashionEurope's biggest steampunk convention heads to Lincoln
Voices
Caustic she may be, but Joan Rivers is a feminist hero, whether she likes it or not
voicesShe's an inspiration, whether she likes it or not, says Ellen E Jones
News
i100
Arts and Entertainment
Star turns: Montacute House
tv
News
ebooksAn evocation of the conflict through the eyes of those who lived through it
News
i100Steve Carell selling chicken, Tina Fey selling saving accounts and Steve Colbert selling, um...
Arts and Entertainment
Unsettling perspective: Iraq gave Turner a subject and a voice (stock photo)
booksBrian Turner's new book goes back to the bloody battles he fought in Iraq
News
i100
Arts and Entertainment
Some of the key words and phrases to remember
booksA user's guide to weasel words
Life and Style
Brave step: A live collection from Alexander McQueen whose internet show crashed because of high demand
fashionAs the collections start, Alexander Fury finds video and the internet are proving more attractive
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Graduate C#.NET Developer (TDD, ASP.NET, SQL)

Negotiable: Harrington Starr: Graduate C#.NET Developer (TDD, ASP.NET, SQL) Su...

Junior SQL DBA (SQL Server 2012, T-SQL, SSIS) London - Finance

£30000 - £33000 per annum + Benefits + Bonus: Harrington Starr: Junior SQL DBA...

C# Web Developer (ASP.NET, JavaScript, MVC-4, HTML5) London

£35000 - £45000 per annum + Benefits + Bonus: Harrington Starr: C# Web Develop...

Senior Data Scientist (Data Mining, RSPSS, R, AI, CPLEX, SQL)

£60000 - £70000 per annum + Benefits + Bonus: Harrington Starr: Senior Data Sc...

Day In a Page

The other Mugabe who is lining up for the Zimbabwean presidency

The other Mugabe who is lining up for the Zimbabwean presidency

Wife of President Robert Mugabe appears to have her sights set on succeeding her husband
The model of a gadget launch: Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed

The model for a gadget launch

Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed
Alice Roberts: She's done pretty well, for a boffin without a beard

She's done pretty well, for a boffin without a beard

Alice Roberts talks about her new book on evolution - and why her early TV work drew flak from (mostly male) colleagues
Get well soon, Joan Rivers - an inspiration, whether she likes it or not

Get well soon, Joan Rivers

She is awful. But she's also wonderful, not in spite of but because of the fact she's forever saying appalling things, argues Ellen E Jones
Doctor Who Into the Dalek review: A classic sci-fi adventure with all the spectacle of a blockbuster

A fresh take on an old foe

Doctor Who Into the Dalek more than compensated for last week's nonsensical offering
Fashion walks away from the celebrity runway show

Fashion walks away from the celebrity runway show

As the collections start, fashion editor Alexander Fury finds video and the internet are proving more attractive
Meet the stars of TV's Wolf Hall... and it's not the cast of the Tudor trilogy

Meet the stars of TV's Wolf Hall...

... and it's not the cast of the Tudor trilogy
Weekend at the Asylum: Europe's biggest steampunk convention heads to Lincoln

Europe's biggest steampunk convention

Jake Wallis Simons discovers how Victorian ray guns and the martial art of biscuit dunking are precisely what the 21st century needs
Don't swallow the tripe – a user's guide to weasel words

Don't swallow the tripe – a user's guide to weasel words

Lying is dangerous and unnecessary. A new book explains the strategies needed to avoid it. John Rentoul on the art of 'uncommunication'
Daddy, who was Richard Attenborough? Was the beloved thespian the last of the cross-generation stars?

Daddy, who was Richard Attenborough?

The atomisation of culture means that few of those we regard as stars are universally loved any more, says DJ Taylor
She's dark, sarcastic, and bashes life in Nowheresville ... so how did Kacey Musgraves become country music's hottest new star?

Kacey Musgraves: Nashville's hottest new star

The singer has two Grammys for her first album under her belt and her celebrity fans include Willie Nelson, Ryan Adams and Katy Perry
American soldier-poet Brian Turner reveals the enduring turmoil that inspired his memoir

Soldier-poet Brian Turner on his new memoir

James Kidd meets the prize-winning writer, whose new memoir takes him back to the bloody battles he fought in Iraq
Aston Villa vs Hull match preview: Villa were not surprised that Ron Vlaar was a World Cup star

Villa were not surprised that Vlaar was a World Cup star

Andi Weimann reveals just how good his Dutch teammate really is
Bill Granger recipes: Our chef ekes out his holiday in Italy with divine, simple salads

Bill Granger's simple Italian salads

Our chef presents his own version of Italian dishes, taking in the flavours and produce that inspired him while he was in the country
The Last Word: Tumbleweed through deserted stands and suites at Wembley

The Last Word: Tumbleweed through deserted stands and suites at Wembley

If supporters begin to close bank accounts, switch broadband suppliers or shun satellite sales, their voices will be heard. It’s time for revolution