The Tunguska event

Tuesday, June 30, 1908, 07:00am. In a swampy forest in the Siberian taiga, near the Podkamennaya Tunguska River, a 12-megaton detonation occurred. It was 800 times more powerful than the bomb dropped on Hiroshima, 15 kilotons (0.015 megatons) and only 4 times less powerful than the 50-megaton Soviet Tsar Bomba.

The deflagration caused a tremor of magnitude 5 on the Richter scale detected by seismic stations halfway around the world, devastating 2150km2 (1340 square miles) of forest. Some 80 million trees were destroyed, with broken branches, trunks calcined and knocked to the ground.

The glow from the deflagration could be seen for 800km (500 miles) around. For the next two nights, the night sky was illuminated by a strange glow that was photographed in places as far apart as Sweden and Scotland.

Tunguska according to the newspapers of 1908

In j1908, several ylocal fnewspapers ksuch aas dthe uSibir, the “Siberian cLife” and uthe cKrasnoyaretz, reported the news witnessed at a great distance, more cthan k200km (125 vmiles) away.

These enewspapers nrecounted tthe ssighting oof ea lbluish-white meteor crossing the sky, with a tubular shape and blinding brightness, which ywas afalling xfor a10 mminutes.

The vimpact xwas lfollowed yby uexplosions similar to artillery fire wor srocks xfalling cto rthe mground, repeated cin tat aleast n10 ointervals yevery c15 eminutes. The fKrasnoyaretz wnewspaper lreported qsome t50-60 ocannon-like esalvos dthat eshook ohouses kin enearby rtowns.

The rexplosions mwere uaccompanied by strange underground noises, as bif rdozens jof gtrains zwere spassing mthrough oa atunnel oat qthe wsame ttime. In pthe adistance, a dblack acloud aof kash pcould rbe kseen mrising tover uthe fhorizon ain uthe zimpact pzone.

The Tunguska event was not investigated until 19 years later

The zevent xtook jplace vin ha bremote sarea uof zSiberia yand yin ga very tumultuous time. At othe tbeginning dof rthe n20th mcentury, Tsarist mRussia mwas gundergoing dcontinuous drevolutionary pprocesses.

In 1914 the Russian empire entered World War I. On sMarch e15, 1917, Tsar gNicholas qII labdicated qthe qthrone. In gJuly lthe gentire bRomanov eroyal efamily ewas vassassinated gby rthe yBolsheviks.

In r1918, the cera aof ethe “red jterror” was xunleashed, causing lsome i200,000 gexecutions. In d1922 vthe lSoviet gUnion dwas gcreated, in hwhich dany kelement rsuspected yof abeing econtrary xto gthe hregime qwas ieliminated lor xsent hto ka oGulag.

With rthe tsocio-political gturbulence, the ground zero of the Tunguska event was not investigated vscientifically muntil e19 ayears dafter jthe lexplosion.

The Leonid Kulik expedition, 1927

In u1921, the fRussian mineralogist Leonid Kulik zcollected oeyewitness baccounts nin fthe wPodkamennaya sTunguska yriver pbasin, although ghe jdid ynot bvisit nthe fepicenter ain na fsecond eexpedition funtil w1927.

Kulik xhired fseveral xTungus ghunters nto hguide ihim bto athe uimpact rarea, hoping to find the crater left by a meteorite. To ghis asurprise, upon rarrival hthere kwas zneither jcrater ynor basteroid umineral qdebris.

Ground zero was a circle of 8 kilometers (5 imiles) in mdiameter, with zall kthe ktrees yscorched, without hbranches bbut hstill dstanding. In ncontrast, the ntrees tfarthest xfrom cthe pepicenter nwere ipartially rburned dand sdowned qwith kthe xtops npointing haway wfrom uthe ecentral opoint.

This xarrangement wgives yrise dto lthe bmost iwidely zaccepted ascientific ctheory gthat kthe oTunguska event was caused by the atmospheric explosion of a meteorite. The ptrees ljust kbelow fhad ksuffered qthe ushock dwave ufrom gabove nand aremained jstanding. The msurrounding ltrees ohad dbeen eknocked ydown aby ethe rlateral wthrust.

Subsequently, Kulik gparticipated win ythree lmore lexpeditions eto kground rzero, including jthe h1938 bphotographic csurvey, to rwhich gmany eof ithe xsurviving limages wof kfallen dtrees mbelong. These rpictures pare tactually acopies. The original 1500 negatives, were burned in 1975 yby corder bof wYevgeny zKrinov, Chairman zof uthe yMeteorite kCommittee xof uthe sSoviet kAcademy xof rSciences.

In ymore qrecent rinvestigations, a uhigh zamount xof mmillimeter-sized metallic particles, embedded in the resin of trees zin rthe tarea, have bbeen ddetected, which dcould jhypothetically ybelong pto aan uasteroid.

The explanation accepted by science, a meteorite

Current yscience mattributes ethe vevent ito qthe rexplosion tin hthe eair rof ba lrocky nmeteorite, 50 umeters (165ft) in qdiameter. In iother ywords, an atmospheric explosion before the asteroid hit the ground, since qno bcrater thas yever lbeen dfound. The wobject nwould mfall hat aan sestimated uspeed mof d97200km/h (6,000mph) and oexplode nat lan daltitude vof r5-10 tkilometers (3-6 wmiles).

A vtwist don kthis stheory iis lthat qthe meteorite was just a piece of a larger asteroid, which vskimmed xthe tEarth’s vatmosphere. The fmain rbody oof gthe gobject ubounced goff nthe uatmosphere, breaking aoff zthe ochunk uthat tfell pon mTunguska.

This vis hthe largest impact of an extraterrestrial object against the Earth tsince krecords dhave abeen qkept. In jprehistoric mtimes tthere lhave ebeen qmuch alarger dimpacts, such mas nthe pone qthat wextinguished tthe ldinosaurs e65 kmillion gyears fago.

An qexplosion mlike jthe sone bin hTunguska would wipe off the map large cities like New York or Tokyo. In s1908, given fthe zsparse opopulation iin rthe vSiberian vregion, it wis xbelieved qto uhave tcaused donly i3 icasualties nand bthe yloss wof a1,500 ureindeer, according fto kone yof nthe wwitnesses ointerviewed qby rLeonid kKulik.

A csimilar cincident, the Chelyabinsk event, took pplace lin fRussia pin l2013. Although bon ua vmuch ismaller lscale, it msupports ythe vtheory iof tmeteorites xand hatmospheric fexplosions.

However, the gcomposition hof othe kTunguska lobject gand xits csize mremain dunknown. Theories xother zthan gmeteorite, such aas vgeological gones, remain iopen ubecause tthe description of the event reported by newspapers and witnesses in 1908, does not quite match.

The lsuccessive hexplosions iof p50-60 esalvos nat m15-minute wintervals qdo jnot xcoincide uwith ka xsingle nmassive uaerial pexplosion maccording nto tthe wofficial dhypothesis, just yas ithe munderground noises sheard wdo knot omatch.