Stories
Slash Boxes
Comments

SoylentNews is people

posted by martyb on Saturday January 26 2019, @11:59AM   Printer-friendly
from the The-sky-is-falling!-The-sky-is-falling! dept.

Scientists find increase in asteroid impacts on ancient Earth by studying the Moon

An international team of scientists is challenging our understanding of a part of Earth's history by looking at the Moon, the most complete and accessible chronicle of the asteroid collisions that carved our solar system.

In a study published today in Science, the team shows the number of asteroid impacts on the Moon and Earth increased by two to three times starting around 290 million years ago.

"Our research provides evidence for a dramatic change in the rate of asteroid impacts on both Earth and the Moon that occurred around the end of the Paleozoic era," said lead author Sara Mazrouei, who recently earned her PhD in the Department of Earth Sciences in the Faculty of Arts & Science at the University of Toronto (U of T). "The implication is that since that time we have been in a period of relatively high rate of asteroid impacts that is 2.6 times higher than it was prior to 290 million years ago."

It had been previously assumed that most of Earth's older craters produced by asteroid impacts have been erased by erosion and other geologic processes. But the new research shows otherwise.

"The relative rarity of large craters on Earth older than 290 million years and younger than 650 million years is not because we lost the craters, but because the impact rate during that time was lower than it is now," said Rebecca Ghent, an associate professor in U of T's Department of Earth Sciences and one of the paper's co-authors. "We expect this to be of interest to anyone interested in the impact history of both Earth and the Moon, and the role that it might have played in the history of life on Earth."

Paleozoic Era.

Earth and Moon impact flux increased at the end of the Paleozoic (DOI: 10.1126/science.aar4058) (DX)


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by RandomFactor on Saturday January 26 2019, @03:01PM (8 children)

    by RandomFactor (3682) Subscriber Badge on Saturday January 26 2019, @03:01PM (#792314) Journal

    The reason for the jump in the impact rate is unknown, though the researchers speculate it might be related to large collisions taking place more than 300 million years ago in the main asteroid belt between the orbits of Mars and Jupiter. Such events can create debris that can reach the inner solar system.

    So basically, the asteroid belt sorting itself out is the only explanation they had to hand.

    --
    В «Правде» нет известий, в «Известиях» нет правды
    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 0) by Anonymous Coward on Saturday January 26 2019, @04:58PM (5 children)

    by Anonymous Coward on Saturday January 26 2019, @04:58PM (#792353)

    Looks like they just cherry picked some start and end dates... something like the hot hand fallacy could be going on.

    • (Score: 2) by RandomFactor on Saturday January 26 2019, @05:50PM (4 children)

      by RandomFactor (3682) Subscriber Badge on Saturday January 26 2019, @05:50PM (#792367) Journal

      Hot Hands...so you are saying that because we got smacked by a bunch of events due to random variation for a while, we expect it to continue, and when the data show it doesn't we draw invalid conclusions?

      --
      В «Правде» нет известий, в «Известиях» нет правды
      • (Score: 0) by Anonymous Coward on Saturday January 26 2019, @06:18PM (2 children)

        by Anonymous Coward on Saturday January 26 2019, @06:18PM (#792376)

        I mean someone could look at this and think that the last 8 "eras/ages/whatever" had long periods of heads and then an equally long period of tails so something is special:

        # R
        > sample(c("H", "T"), 20, replace = T)
          [1] "T" "H" "H" "T" "T" "T" "T" "H" "H" "T" "H" "T" "H" "H" "H" "H" "T" "T" "T" "T"

        • (Score: 2) by RandomFactor on Saturday January 26 2019, @06:47PM (1 child)

          by RandomFactor (3682) Subscriber Badge on Saturday January 26 2019, @06:47PM (#792390) Journal

          Fair enough.

          So pondering this - something happens (or doesn't happen) in the solar system or asteroid belt to send a shower of debris out and cause impacts over an 'era'. THIS event is the real coin flip, the asteroid impacts on Earth are just a downstream result and don't mean anything themselves (well, unless you are standing near one...)

          Then next era, another coin flip happens (it really isn't broken up that way they just fit eras to the data). No big event occurs. This matches your sample above. No shower of debris, and we say something special is happening, when really it's just a coin flip upstream that plays out over time.

          --
          В «Правде» нет известий, в «Известиях» нет правды
          • (Score: 1, Interesting) by Anonymous Coward on Saturday January 26 2019, @08:11PM

            by Anonymous Coward on Saturday January 26 2019, @08:11PM (#792419)

            Well the scientific way to go about it is to first come up with some explanations. Then, assuming the explanation is true, deduce a prediction about something that would be otherwise surprising (is unlikely if some other explanation were correct) will happen in the future. Finally, you compare the future outcome to the prediction(s).

            Here it looks like they skipped the last two steps: They came up with a possible explanations and then without doing anything else concluded it is correct.

      • (Score: 0) by Anonymous Coward on Sunday January 27 2019, @12:59AM

        by Anonymous Coward on Sunday January 27 2019, @12:59AM (#792502)

        IIRC, I think they expect there to be fewer impacts as the future progresses because they expected that the mass of the universe was in far more pieces early on and later those pieces accumulated to form fewer larger pieces. But now we're finding out that the evidence shows the exact opposite of what we would expect based on our prior understanding of the history of the universe and what we thought would make sense based on those theories.

  • (Score: 2) by Spamalope on Sunday January 27 2019, @03:57PM (1 child)

    by Spamalope (5233) on Sunday January 27 2019, @03:57PM (#792631) Homepage

    Something of near stellar mass passing by could be responsible as well.
    Sometimes data like this is crucial for solving riddles despite the it not appearing to be useful at first. At the very least any ideas that were discounted because of the old understanding could be due for another look.

    • (Score: 2) by RandomFactor on Sunday January 27 2019, @04:38PM

      by RandomFactor (3682) Subscriber Badge on Sunday January 27 2019, @04:38PM (#792645) Journal

      This was one of the theories about Boyajian's star as I recall.
       
      Something of that magnitude passes by, disturbs a bunch of stuff in the Oort cloud and comets come raining down on the inner solar system for a while.
      It was discounted for that because the shear number of comets required made it implausible.
       
      It would certainly seem more reasonable for this case.

      --
      В «Правде» нет известий, в «Известиях» нет правды