Asteroid Day

[lpetrich]

Asteroid Day TV - Asteroid Day - from About Asteroid Day - Asteroid Day

Asteroid Day is a dynamic awareness and educational program to inspire the world about asteroids – their role in the formation of our universe, how we can use their resources, how asteroids can pave the way for future exploration and finally how we can protect our planet from asteroid impacts. Asteroid Day events are held on 30 June each year to mark the anniversary of the 1908 Tunguska impact. Asteroid Day events are largely independently organized around the world for people of all ages and are mostly free-of-charge. Asteroid Day is a program run by the Asteroid Foundation, a Luxembourg nonprofit organization.

...
Asteroid Day takes place annually on June 30. It is a global awareness campaign where people from around the world come together to learn about asteroids, the impact hazard they may pose, and what we can do to protect our planet, families, communities, and future generations from future asteroid impacts. Asteroid Day is held each year on the anniversary of the largest impact in recent history, the 1908 Tunguska event in Siberia. A relatively small asteroid, about 40 meters across or the size of a modest office building, devastated an unpopulated area about the size of a major metropolitan city. Regionally organised large and small events are held on Asteroid Day, and range from lectures and other educational programmes to live concerts and broader community events, to raise public awareness of the need for increased detection and tracking of asteroids.

The Tunguska disaster - 107th anniversary - today is its 111th anniversary - For Almost 100 Years, Scientists Puzzled Over The Tunguska Event -  Tunguska event

It was like this - Meteor Hits Russia Feb 15, 2013 - Event Archive - YouTube - but it was a hundred times more powerful.

I first learned about that disaster in my childhood, and I remember from my childhood one of Isaac Asimov's science essays, "The Rocks of Damocles", about asteroid impacts being a threat to us. Asteroid Day is about that threat and what we can do about it.

 

[skepticalbip]

It is an odd human quirk to obsess over possible disasters, regardless of how unlikely, especially if there is nothing they can do to stop them.

 

[bilby]

Narrator: "We landed at ten thirty am ship's time; six thirty pm asteroid time".

Spike Milligan, in broad Irish accent: "Ha-Ha! If asteroid time, the pubs will be open!"

 

[lpetrich]

Tunguska blast simulation by Sandia lab - YouTube

3D simulation of a 5 megaton explosion that is initiated (asteroid breaking up due to aerodynamic stress and becoming a super-hot fireball) 12 km above the surface, for an asteroid entering at an angle of 35 degrees above the horizontal. Box dimensions are 40 km wide, 20 km high. Colors indicate speed. The hot fireball does not reach the surface, but descends to an altitude of 5 km before buoyantly rising. At ground zero, the blast wave comes from directly above, consistent with observations of standing trees at the Tunguska epicenter. Moving away from ground zero, the outward component of blast wind speed quickly picks up and levels all trees radially from zero point. Note how the direct and reflected shockwaves reinforce near the ground (brighter area at the lower left indicating shock strengthening). This phenomenon is known as the Mach stem and further adds to the destruction caused by an airburst.

This is an artist's rendition of how the Tunguska event might have looked from the windows of a nearby airliner : space - a big airburst fireball.

The Tunguska Impact--100 Years Later | Science Mission Directorate

June 30, 2008: The year is 1908, and it's just after seven in the morning. A man is sitting on the front porch of a trading post at Vanavara in Siberia. Little does he know, in a few moments, he will be hurled from his chair and the heat will be so intense he will feel as though his shirt is on fire.

That's how the Tunguska event felt 40 miles from ground zero.

That article's numbers:
Size: 120 ft / 40 m
Mass: 220 million lb / 100 thousand mt
Speed: 33,500 mph / 54,000 km/h / 12 km/s
Breakup altitude: 28,000 ft / 8,500 m
Temperature: 44,500 F / 25,000 K
Explosion energy: 185 Hiroshimas / 3 megatons / 12 petajoules
Estimates from elsewhere may differ.

 Tunguska event,  Chelyabinsk meteor

The Chelyabinsk meteor was only a tenth as massive with only a tenth the explosive force, but it exploded much higher up, at about 30 km.

The Tunguska object was likely a part of the Taurid meteor swarm -- Study investigates potential risk of Taurid meteor swarm -  Taurids associated with  Comet Encke.

 

[lpetrich]

I've written a story that is based on the extraterrestrial-spaceship hypothesis for that event.

Tunguska and the Titanic - The Two Ships - Wattpad
Tunguska and the Titanic on FictionPad
Tunguska and the Titanic on Google Drive

From it:

When our investigators arrived at the scene, they found a huge explosion site, with trees knocked down for miles around, and with nothing remaining of the ship. Nothing.

 

[lpetrich]

Research Unearths Clues About Tunguska for International Asteroid Day | Digital Trends
Some 2000 square kilometers / 770 square miles of forest was flattened from its explosion

That's equivalent to a circle with radius 25 km / 15 mi

They discovered it was size of a five-story building and that it exploded 15 miles above the ground, in a 550 kiloton explosion. It is estimated that a meteor of this size could impact the Earth every 10 to 100 years on average.

Computer modellers took this data and applied it to the Tunguska event. They found that the event was likely caused by a stony meteor rather than an icy one, and that it must have been between 164 and 262 feet in diameter. It entered the atmosphere at a whopping 34,000 miles per hour, and it exploded above the surface at 6 to 9 miles of altitude, which is why there was no impact crater or fragments discovered.

Chelyabinsk:
Size: 5 stories / 50 ft / 16 m
Breakup altitude: 15 mi / 79,000 ft / 24 km
Tunguska:
Size: 164 - 262 ft / 50 - 80 m
Breakup altitude: 6 - 9 mi / 32,000 - 48,000 ft / 10 - 14 km

The Chelyabinsk one was much less devastating because it broke up much higher.

 

[Angry Floof]

It is an odd human quirk to obsess over possible disasters, regardless of how unlikely, especially if there is nothing they can do to stop them.

A lot of problem solving comes from such obsession.

 

[Jimmy Higgins]

It is an odd human quirk to obsess over possible disasters, regardless of how unlikely, especially if there is nothing they can do to stop them.

As Vonnegut put it, mankind is a highly suicidal species, so it only seems natural to obsess over our own extinction.

 

[bilby]

It's a pretty small risk - if there's an asteroid strike that size once every 100 years, and cities cover about 3% of tbe Earth's surface, the crude frequently of a city being hit is going to be in the order of every 3,000 years.

And we've only been concentrated in urban areas for a couple of hundred years so far, so it's not surprising no cities have yet been destroyed by asteroids. The risk to any given city is, of course, far lower still; And with a lifespan of only 80 or so years, the risk to any individual human is minuscule - It's FAR less likely that you will be killed by a meteor than by lightning.

OTOH, lightning is unlikely to cause our species to become extinct, but if we survive for long enough, space debris could do it. As Larry Niven said, "The dinosaurs became extinct because they didn't have a space program".

 

[Treedbear]

It is an odd human quirk to obsess over possible disasters, regardless of how unlikely, especially if there is nothing they can do to stop them.

As Vonnegut put it, mankind is a highly suicidal species, so it only seems natural to obsess over our own extinction.

I like to look at the big picture and think the one thing that might distinguish us among the other species is the ability to save the planet from the next major extinction event.

 

[Loren Pechtel]

Duck and cover!