What happened in Tunguska in 1908? ( This huge explosion might
have been caused by an asteroid) - ¿Qué ocurrió en Tunguska en 1908?
Let me tell you something: none of the people watching this video were alive
when the Tunguska event happened. But I’m pretty sure some of you have heard about it:
the greatest explosion in modern history, caused by the impact of a meteoroid.
To have witnessed that, you must be 115 today, which is… unlikely.
It was June 30, 1908: the Russian summer had just started.
That morning, a roar shook the territories around the Stony Tunguska River, in present-day Siberia.
80 million trees fell to the ground, almost instantaneously. Some witnesses believed this
huge ball of fire in the sky would be the last thing they would have seen before passing away. If
you were there you could see it shine as bright as the sun. Some perceived it in London, where it was
midnight, and they swear it was possible to read a newspaper without the aid of artificial light.
But what do we exactly know about this huge ball of fire? And what role does it
play in the study of asteroids? Watch this video if you want to know more!
(roll intro)
--- Tunguska: location and event
Tunguska
River is made of two roughly parallel rivers in Western Siberia, both tributaries of the
Yenisey river, one of the longest rivers in Asia. In this region, the cold season prevails from
late September to mid-June in the north and from mid-October to late April in the south.
Even summer is cool in the northern basin, with average temperatures of 46 to 54 °F (8 to 12 °C)
in July, when frosts may still occur; but summer is warm in the south, with July averages between
64 and 68 °F (18 and 20 °C). Precipitations are not rare during summer, but one thing is sure:
that morning of June 1908, no one was expecting a meteoroid to fall so loudly.
It happened at 7:14 local time, and the sound of the explosion was heard one thousand kilometers
away. It felled 80 million trees over an area of 2 thousand square kilometers.
Later on, scientists estimated that the shock wave produced could have been similar to an earthquake
measuring 8 on the Ritcher scale, among the most powerful earthquakes ever recorded.
--- Reports
Almost as soon as a meteor burned up in the sky above France on February 13, 2023,
firsthand accounts appeared on the Internet, complete with videos and photos of the event.
But in 1908, when an asteroid or comet fragment exploded about five miles above
the earth’s surface, destroying 800 square miles of boreal forest in central Siberia and uprooting
80 million trees, the area was so isolated that it took decades for eyewitness reports to emerge.
There are about 70 reports in Russian newspapers and in the form of written
letters shortly after the event. For instance, here’s what a peasant who
had been living about forty miles from the site of impact wrote in a letter to report his experience:
“It was 1908 in the month of June about 8 o’clock in the morning; I…was occupied with work around
my hut. I sat on the open porch with my face toward the north and at that time there arose,
in a moment, a conflagration that gave off such heat that it was impossible to remain
sitting—it almost burned the shirt off me…But to make up for that, this conflagration endured
only a very short time; I had time only to cast my eyes in that direction and see how
large it was when in a moment it vanished…After this vanishing, it grew dark, and at the same
time there was an explosion which threw me off the open porch about seven feet or more”
The mysterious Tunguska Event has inspired a range of theories since
it happened without much observation. Names such as black holes, antimatter,
and even Nikola Tesla have been suggested as possible causes.
The source of the explosion is still being debated by scientists, but all that can be confidently
said is that it was either a comet or an asteroid, measuring between 164 and 262 feet across.
Let me explain to you why it is so hard to assess what was the real cause of the Tunguska event.
First, we need to know what a meteoroid is, and what happens to it when it impacts the atmosphere.
--- The impact of meteoroids
Meteoroids are small pieces of rock or iron that orbit the sun, just like planets, asteroids,
and comets. They can be found throughout the solar system, ranging from the inner rocky
planets to the gas giants of the outer planets, as well as the Kuiper belt and Oort cloud.
Meteoroids vary in speed and orbit, with the fastest traveling at 42 km/s, and most originating
from asteroid collisions taking place in a region between Mars and Jupiter called the asteroid belt.
Comets also generate debris that forms meteoroid streams. A small number of meteoroids come from
the Moon and Mars when they are impacted by celestial bodies, further contributing
to ‘space weathering’. Most meteoroids are made of minerals like silicon, and oxygen
and heavier metals like nickel and iron. Iron and nickel-iron meteoroids tend to be dense, whereas
stony meteoroids are more lightweight and fragile. The movement of meteoroids is monitored by space
agencies such as NASA and ESA for two main reasons: potential impact with spacecraft
and potential impact with Earth. Engineers must prepare and equip spacecraft to avoid
or withstand meteoroid impacts, taking into account three different “meteoroid environments”:
the sporadic environment, the shower environment, and the lunar environment.
The sporadic environment describes the threat of meteoroids created by asteroids or comets.
Engineers must determine what area of the spacecraft is most
vulnerable to sporadic meteoroids, and prepare stronger shielding mechanisms.
The shower environment describes the threat of meteoroid streams associated with comets
passing through Earth’s orbit. On Earth, these debris fields are associated with meteor showers.
Engineers must be able to maneuver the spacecraft to take its most vulnerable
areas out of the path of the meteoroid stream. The lunar environment describes the threat of
meteoroids to astronauts or facilities on the moon. Although there have been no long-term
astronaut stays on the moon, engineers have designed space suits, vehicles, and habitats
that can withstand meteoroid impacts. When a meteoroid passes through Earth’s
atmosphere, it heats up and causes gases around the meteoroid to glow brightly,
this is called a meteor. Most meteoroids become harmless before they reach the surface, but very
large meteors called bolides may explode in the atmosphere with the force of 500 kilotons of TNT.
These meteors may cause burns, death, and damage to buildings and crops. Impact events such as
the one 65 million years ago, may lead to the extinction of much of life on Earth.
On Earth, protective space suits, vehicles, and habitats have been
designed to withstand meteoroid impacts. However, not only meteoroids are a threat
here on Earth. Spacecrafts too can be hit. That’s why they must be designed to protect against any
meteoroid impact, providing the highest grade of shielding measures. For example, spacecraft must
take its most vulnerable areas out of the path of the meteoroid stream in the shower environment.
As you can see, monitoring the movement of meteoroids is a vital measure to ensure the
safety of spacecraft and the prevention of any potential catastrophic impacts.
Moreover, scientists are developing some techniques to deviate the trajectory of hazardous
objects, that could present a threat to humans. If you are interested in the subject, we can make a
video about it! Let us know in the comment below! In any case, we have to be ready. Perhaps,
in the future, we will have the chance to avenge dinosaurs.
--- COMET OR ASTEROID?
We said the nature of the Tunguska impactor is still debated among scientists.
If a meteoroid falls from space, we are expecting to find a crater. Somewhere,
near Tunguska, there should be a large hole, where the meteoroid stuck in the ground,
just like the crater left by a sayan capsule.
This crater, however, has never been found. In order to explain the absence of a crater,
It has been hypothesized that the passage of the asteroid through the atmosphere
caused pressures and temperatures to build up to a point where the asteroid
abruptly disintegrated in a huge explosion. The destruction would have to have been so
complete that no remnants of substantial size survived, and the material scattered
into the upper atmosphere during the explosion would have caused the skyglow.
This would also explain why no Tunguska fragments were found so far.
Actually, some expeditions were have been sent to Tunguska, but they didn’t result in confirmed
meteorite fragments, and, over the years, an aura of mystery surrounded the 1908 meteor explosion.
The thing is…finding this fragment is no picnic, and it is probably even harder than
finding a crater, because the territory is sparsely populated, and reports don’t give a
clear hint on where the event exactly happened. Scientists have tried to restrict the area by
reading letters and reports in newspapers, but it’s really hard to assess the exact location.
However, the tress…could give us a hint about the real nature of the impactor.
We said a huge number of them were felled, due to the shock wave.
Some clever Italian researchers from Bologna have decided to extract resin from the core of
the trees in the area of impact to examine trapped particles that were present during the 1908 event.
They found high levels of material commonly found in rocky asteroids, and rarely found in comets.
But other scientists are strongly convinced it was a comet.
F.J.W. Whipple, for instance, hypothesized that the Tunguska body was a comet composed
of dust and volatiles. Further support was found in the "bright nights" seen
across Eurasia post-impact, likely due to dust and ice spread from the comet's tail.
Who knows who’s right? Probably we will never have a definitive answer.
What we do know, though, is that Tunguska signed a new era in the study of near-earth objects.
It showed us how fragile we are. But we are also very clever,
and I’m going to prove it to you by talking about the brand new NASA’s successful mission: DART.
--- DART MISSION
The NASA-designed DART mission is a critical part of efforts to protect our planet from
the devastating impacts of near-Earth objects. By intentionally crashing a spacecraft into an
asteroid, the mission measured the effect of the collision on the asteroid’s speed and trajectory:
the DART spacecraft successfully collided with the asteroid Dimorphos
on 26 September 2022 and shortened its orbit by 32 minutes changing its path.
This data provided us invaluable insight into the impact of large space rocks on our planet,
including their potential to cause catastrophic collisions like the Tunguska event of 1908.
With DART, we’ll be able to hone our understanding of how to divert asteroids from an Earth-bound
trajectory that could deliver a devastating blow. The mission will also provide critical insights
into the physics of asteroid impacts, allowing us to better understand the energy released from such
a collision and its effects. Furthermore, DART could help to identify any resources contained
within asteroids, providing an exciting opportunity for future space exploration.
Overall, the DART mission represents an unprecedented step forward in our
capacity to protect and explore our planet, ensuring a safer future for everyone.
Isn’t it incredible? We are able to deflect an asteroid in space,
changing its trajectory FOREVER! We are amazing.
Hey! This video ends here: Thanks for watching! What do you think about the Tunguska event? Was
it a comet or an asteroid? Let us know in the comments below! See you next time on the channel.