Page 1 of 1

APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 4:08 am
by APOD Robot
Image Manicouagan Impact Crater from Space

Explanation: Orbiting 400 kilometers above Quebec, Canada, planet Earth, the International Space Station Expedition 59 crew captured this snapshot of the broad St. Lawrence River and curiously circular Lake Manicouagan on April 11. Right of center, the ring-shaped lake is a modern reservoir within the eroded remnant of an ancient 100 kilometer diameter impact crater. The ancient crater is very conspicuous from orbit, a visible reminder that Earth is vulnerable to rocks from space. Over 200 million years old, the Manicouagan crater was likely caused by the impact of a rocky body about 5 kilometers in diameter. Currently, there is no known asteroid with a significant probability of impacting Earth in the next century. But a fictional scenario to help practice for an asteroid impact is on going at the 2019 IAA Planetary Defense Conference.

<< Previous APOD This Day in APOD Next APOD >>

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 6:13 am
by Boomer12k
A reminder that we still live in a potential shooting gallery....

Nice image!!
:---[===] *

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 6:56 am
by Case
From NatGeo:
Ten biggest known hits, in order of age:
  1. Vredefort Crater, South Africa. 2 billion years ago. 190 km wide.
  2. Sudbury Basin, Canada. 1.8 billion years ago. 130 km wide.
  3. Acraman Crater, Australia. 580 million years ago. 90 km wide.
  4. Woodleigh Crater, Australia. 364 million years ago. 120 km wide.
  5. Manicouagan Crater, Canada. 215 million years ago. 100 km wide.
  6. Morokweng Crater, South Africa. 145 million years ago. 70 km wide.
  7. Kara Crater, Russia, 70 million years ago. 65 km wide.
  8. Chicxulub Crater, Mexico. 65 million years ago. 300 km wide.
  9. Popigai Crater, Russia. 36 million years ago. 100 km wide.
  10. Chesapeake Bay Crater, United States, 35 million years ago. 85 km wide.

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 11:42 am
by orin stepanek
A ring lake? Very intriguing! 8-) :clap: :rocketship:

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 12:00 pm
by De58te
Interesting not just for the view of the Manicougan Crater, but there is also an anomaly captured in the photo. I take it that it is the Saint Lawrence River in the centre lower portion of the photograph. To the left of it appears to be a secondary off branch of the river. Right at the bottom border of this branch, and this appears to be out of place for Quebec, but isn't that a screen capture of the Loch Ness monster lunging up out of the water at the Space Station? I can see the huge head opening its mouth and the skinnier snake like body below.

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 1:01 pm
by Chris Peterson
Boomer12k wrote: Thu May 02, 2019 6:13 am A reminder that we still live in a potential shooting gallery...
No, we live in an actual shooting gallery!

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 2:19 pm
by Guest
There's a typo in the hyperlink about the Planetary Defense Conference

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 7:37 pm
by Guest
De58te wrote: Thu May 02, 2019 12:00 pm Interesting not just for the view of the Manicougan Crater, but there is also an anomaly captured in the photo. I take it that it is the Saint Lawrence River in the centre lower portion of the photograph. To the left of it appears to be a secondary off branch of the river. Right at the bottom border of this branch, and this appears to be out of place for Quebec, but isn't that a screen capture of the Loch Ness monster lunging up out of the water at the Space Station? I can see the huge head opening its mouth and the skinnier snake like body below.
Not a branch of the St Lawrence, but Chaleur Bay with the mouth of the Restigouche River at the top. That apparition you see is probably smoke from the Fireship of Chaleur Bay, though it could be OgoPogo out for a holiday:)

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 8:48 pm
by Jim Leff
Regarding the impact simulation program, there’s a lot of very dry technical material, but this seems to be the one handling big-picture policy/strategy (ie “what do we do??”) overview. If you’re going to watch just one, this might be a good one: https://m.youtube.com/watch?feature=you ... pIkb-BH4R0

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Thu May 02, 2019 10:12 pm
by Chuck O'Dale
In the image are also the Charlevoix, Isl Rouleau and Presqu'ile impact craters. http://craterexplorer.ca/manicouagan-impact-structure/

Re: APOD: Manicouagan Impact Crater from Space (2019 May 02)

Posted: Fri May 03, 2019 2:33 am
by MarkBour
Jim Leff wrote: Thu May 02, 2019 8:48 pm Regarding the impact simulation program, there’s a lot of very dry technical material, but this seems to be the one handling big-picture policy/strategy (ie “what do we do??”) overview. If you’re going to watch just one, this might be a good one: https://m.youtube.com/watch?feature=you ... pIkb-BH4R0
I'm very much enjoying reading and viewing the materials related to the 2019 IAA Planetary Defense Conference and their ongoing simulation, which is found in the APOD caption's final 3 links.

The first punch from a *SUPER* meteor shower?

Posted: Fri May 03, 2019 12:59 pm
by neufer
https://en.wikipedia.org/wiki/Triassic%E2%80%93Jurassic_extinction_event wrote:
<<The Triassic–Jurassic extinction event marks the boundary between the Triassic and Jurassic periods, 201.3 million years ago, and is one of the major extinction events of the Phanerozoic eon. This event vacated terrestrial ecological niches, allowing the dinosaurs to assume the dominant roles in the Jurassic period. This event happened in less than 10,000 years and occurred just before Pangaea started to break apart.

Some have theorized that an impact from an asteroid or comet may have caused the Triassic-Jurassic extinction, similar to the extraterrestrial object which was the main factor in the Cretaceous-Paleogene extinction about 66 million years ago, as evidenced by the Chicxulub crater in Mexico. However, so far no impact crater of sufficient size has been dated to precisely coincide with the Triassic–Jurassic boundary.

Nevertheless, the late Triassic did experience several impacts, including the second-largest confirmed impact in the Mesozoic. The Manicouagan Reservoir in Quebec is one of the most visible large impact craters on Earth, and at 100 km in diameter it is tied with the Eocene Popigai crater in Siberia as the fourth-largest impact crater on Earth. Olsen et al. (1987) were the first scientists to link the Manicouagan crater to the Triassic-Jurassic extinction, citing its age which at the time was roughly considered to be late Triassic. More precise radiometric dating by Hodych & Dunning (1992) has shown that the Manicouagan impact occurred about 214 million years ago, about 13 million years before the Triassic-Jurassic boundary. Nevertheless, the Manicougan impact did have a widespread effect on the planet; a 214-million-year-old ejecta blanket of shocked quartz has been found in rock layers as far away as England and Japan. There is still a possibility that the Manicouagan impact was responsible for a small extinction midway through the late Triassic at the Carnian-Norian boundary, although the disputed age of this boundary (and whether an extinction actually occurred in the first place) makes it difficult to correlate the impact with extinction. Onoue et al. (2016) alternatively proposed that the Manicouagan impact was responsible for a marine extinction in the middle of the Norian which impacted radiolarians, sponges, conodonts, and Triassic ammonoids. Thus, the Manicouagan impact may have been partially responsible for the gradual decline in the latter two groups which culminated in their extinction at the Triassic-Jurassic boundary.

Other Triassic craters are closer to the Triassic-Jurassic boundary but also much smaller than the Manicouagan reservoir. The eroded Rochechouart crater in France has most recently been dated to 201 ±2 million years ago, but at 25 km across, it appears to be too small to have affected the ecosystem. Other putative or confirmed Triassic craters include the 80 km wide Puchezh-Katunki crater in Eastern Russia, the 40 km wide Saint Martin crater in Manitoba, the 15 km wide Obolon' crater in Ukraine, and the 9 km wide Red Wing Creek structure in North Dakota. Spray et al. (1998) noted an interesting phenomenon, that being how the Manicoagan, Rochechoart, and Saint Martin craters all seem to be at the same latitude, and that the Obolon' and Red Wing craters form parallel arcs with the Rochechoart and Saint Martin craters, respectively. Spray and his colleagues hypothesized that the Triassic experienced a "multiple impact event", a large fragmented asteroid or comet which broke up and impacted the earth in several places at the same time. Such an impact has been observed in the present day, when Comet Shoemaker-Levy 9 broke up and hit Jupiter in 1992. However, the "multiple impact event" hypothesis for Triassic impact craters has not been well-supported; Kent (1998) noted that the Manicouagan and Rochechoart craters were formed in eras of different magnetic polarity, and radiometric dating of the individual craters has shown that the impacts occurred millions of years apart.>>