Illustration by Detlev van Ravenswaay, Science Source
Published February 14, 2013
There's one physical connection that isn't going down after Valentine's Day this year: Earth and asteroid.
The asteroid known as 2012 DA14 will narrowly miss Earth this Friday, the closest asteroid flyby on record. But the planet has not always been so lucky.
Earth's craters are enduring testaments to direct asteroid hits. And though millions—in some cases billions—of years of erosion have made it difficult to determine the exact size of the meteorites, there is a general scientific consensus around the world's largest craters, which mark the largest asteroid impacts.
Here are the ten biggest known:
1. Vredefort Crater
Asteroid impact date: Estimated 2 billion years ago
Location: Free State, South Africa
Specs: Also known as the Vredefort Dome, the Vredefort crater has an estimated radius of 118 miles (190 kilometers), making it the world's largest known impact structure. This crater was declared a UNESCO World Heritage Site in 2005.
2. Sudbury Basin
Asteroid impact date: Estimated 1.8 billion years ago
Location: Ontario, Canada
Specs: The Sudbury Basin is considered one of largest impact structures on Earth, with an estimated diameter of 81 miles (130 kilometers). Dating back 1.8 billion years, it is also one of the oldest known impact structures in the world.
3. Acraman Crater
Asteroid impact date: Estimated 580 million years ago
Location: South Australia, Australia
Specs: Located in what is now Lake Acraman, this impact structure has an estimated diameter of 56 miles (90 kilometers).
4. Woodleigh Crater
Asteroid impact date: Estimated 364 million years ago
Location: Western Australia, Australia
Specs: This crater is not exposed at the surface and has led to many discrepancies regarding its actual size. Reports on its diameter vary from 25 to 75 miles (40 to 120 kilometers).
5. Manicouagan Crater
Asteroid impact date: Estimated 215 million years ago
Location: Quebec, Canada
Specs: This impact crater formed what is now Lake Manicouagan. Even with erosion, it's considered one of the largest and best-preserved craters on Earth, with an estimated diameter of 62 miles (100 kilometers).
6. Morokweng Crater
Asteroid impact date: Estimated 145 million years ago
Location: North West, South Africa
Specs: Located near the Kalahari Desert in South Africa, this crater contained the fossilized remains of the meteorite that created it.
7. Kara Crater
Asteroid impact date: Estimated 70.3 million years ago
Location: Nenetsia, Russia
Specs: Now greatly eroded, the Kara crater is a non-exposed impact structure in Russia. Some have claimed that the impact structure actually consists of two adjacent craters: the Kara and the Ust-Kara crater.
8. Chicxulub Crater
Asteroid impact date: Estimated 65 million years ago
Location: Yucatán, Mexico
Specs: Located on the Yucatán Peninsula in Mexico, many scientists believe that the meteorite that left this crater caused or contributed to the extinction of the dinosaurs. Estimates of its actual diameter range from 106 to a whooping 186 miles (170 to 300 kilometers), which if proved right could mean it's the biggest.
9. Popigai Crater
Asteroid impact date: Estimated 35.7 million years ago
Location: Siberia, Russia
Specs: Russian scientists claim that this crater site contains trillions of carats of diamonds, making it one of the largest diamond deposits in the world. These diamonds have been referred to as "impact diamonds."
10. Chesapeake Bay Crater
Asteroid impact date: Estimated 35 million years ago
Location: Virginia, United States
Specs: Discovered in the early 1980s, the Chesapeake Bay Crater is located approximately 125 miles (201 kilometers) from Washington, D.C. Some estimates suggest this crater is 53 miles (85 kilometers) wide.
I made a map of them here.
There is always more to a story than meets the eye and if it were not for laws passed by the guilty to protect the guilty, the public would know of the perpetrators of injustices before they are six feet under.
Was DA14 real? Probably, but possibly not. People often believe what they read, especially when legitimacy is implied by a position in a societal hierarchy. I would believe a scientist coming back from the field with data, the one who collected it and speaking face-to-face. But these days with so many ways to falsify data, the Internet where nothing is real, heartless and biased corporate interest in science and upper management of scientific organizations being leaned on by partisan international organizations, the truth is becoming more elusive.
Was it a random event that the Russian-Chelyabinsk meteor, biggest in a hundred years (Tunguska 1908) would arrive hours before NASA's 2012 DA14 to thoroughly upstage it? I think not...
My blog post on this upstaging of NASA.
I am leading a group of grade 8,9 students under the guidance of the Canadian Planetary Science Center to check out an unusual lake called Red Berry Lake in central Saskatchewan Canada.
We think it might be a potential impact crater because of it's unusual features, surrounded by a ring of hills. We are going looking for "shock rock". We have been given a whole bunch of indicators to look for. It would be very cool if a grade 7 and 8 science class got to be part of finding an impact crater.
Please look up Redberry Lake on Google Maps and see what you think. It is also a much deeper than average lake in our area and it is a salt water body as the ring of hills does not let water flow out of it.
Tell me what you think, and if National Geographic, if you want to help us in early June we would Love your help.
@Chris Thomas Wakefield This kind of stunning paranoia is becoming less and less surprising these days but it's still a bit of a shock to know that some are so unashamedly willing to display it to this degree on a public forum. I'm also surprised you were able to get an internet hook-up in a cave! Ain't technology great!
@Chris Thomas Wakefield You need to wake up and smell reality. I know it's nice to think that the whole world is out to get us but reality isn't that exciting. Scientists are here to help and NASA is one of the greatest things that has ever happened to humanity. Go to a doctor, get some medicine, and get better.
@Douglas Baugh @Chris Thomas Wakefield Mr Baugh, why do you assume that I wouldn't be aware of what I am doing? You hit on the key point of my motive: "unashamedly". Unless you are implying that I should be ashamed, which is really a reflection of the one who would say that of another who has honestly gone to a fair amount of work in my blog posts. If you have any knowledge of those who are paranoid you would see that I don't display that pattern. But it's easy to call somebody down, especially when they stand up and say what they believe (and thoroughly research) in a public forum. For your actions, I would say that you could take the advice of your own ill-advised comments.
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