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  • Category: Miscellaneous

    Why is the moon full of craters

    While discussing about What colour does the sky look from the moon, we have seen that the lack of atmosphere resulted in the sky looking black from the moon, whereas on earth it is blue, orange and all sorts of colour. Another marked difference between earth and its moon is that the moon is badly pockmarked with craters. In fact, they are so numerous that a few of them are even visible from earth through ordinary telescopes. On the other hand, we hardly see any such craters on earth's surface. We all know that these craters have been formed on moon due to the asteroids and meteors that have collided its surface from time to time. Is it that moon has been struck with more such meteors compared to earth or is it again the lack of atmosphere that has something to do with it? One more thing. If we assume that moon gets struck by meteors more frequently than earth, won't it be dangerous for mankind to have a permanent base in moon?
  • #705533
    In the universe, there are many small bodies which are moving in great circles or parabolic paths around the heavenly bodies like sun or other such stars and planets. They are large in numbers and many of them distract and divert and fall on the nearby planets. Scientifically, these are known as meteorites. Some of us might have seen the dazzling meteoritic showers in the night sky in a particular time of the year when Earth is exposed to the stream of such small bodies in the space. When these bodies fall on Earth they get friction with the Earth atmosphere and burn and most of them turn in ash and vapours before reaching the Earth surface. Rarely some of them fall on Earth without annihilating and create disasters. If they are big in size they create craters also.

    On moon there is no atmosphere and so no friction and no burning of these bodies falling on it and so they simple create craters of different size on it due to the severe impact.

    Knowledge is power.

  • #705537
    It is not that there have been fewer craters in the earth, there was a time when earth and moon both have hit by the craters, but the earth has some processes that have helped remove in craters' existence.
    Erosion is one of the important phenomena in the earth, there are weather, water, and plants which increase this process.
    The Moon has no erosion because it has no atmosphere. This means that it has no wind, has no weather, and certainly has no plants so it cannot remove the marks on its surface.

    The second thing is something called tectonics. Tectonics are processes that cause the surface of our planet to form new rocks, get rid of old rocks, and move over millions of years.
    Very few rocks on Earth are as old as rocks on the moon. The moon has not done tectonics for billions of years. There is too much time for the crater to form and persist.

    The Moon may attract fewer bits of space rock than Earth, but the Moon is powerless to do anything about it once it hits. Once an object hits the moon, that event freezes over time. On the other hand, the Earth simply dissipates these influences and moves on with its life.

    Swati Sharma

    Keep your Face to the SunShine

  • #705538
    Since no one has fully explored the moon in detail making comments or arriving at a general statement would be foolish submission. But what I reason that out of so may planets, the living has been made possible only on the earth and other planets does not have oxygen and water which is the prerequisite of the mankind living. In that case most of the other planets are filled with craters, mountains and other minerals to which we are not aware. Since the nature is abundant and earth has all the ingredients to live , we must be satisfied and should not explore other worlds which be treated as greedy.
    K Mohan @ Moga
    'Idhuvum Kadandhu Pogum "
    Even this challenging situation would ease

  • #705543
    Yes, Earth also had many craters especially due to the impacts of bigger bodies which could not be turned to ashes in the atmosphere due to the heat of the friction. Further, the weathering and erosion have erased those marks. But we can find them in the seismic records of the Earth surface. Anyway, you have well mentioned that aspect in your response.
    Humans are always curious and inquisitive and in that pursuit imagine to dwell on the other planets also. It is too ambitious to think in those frontiers but science is always like that. It is the inherent character of scientific pursuits to explore the unknown everywhere including Earth.

    Knowledge is power.

  • #705622
    It is a fact that craters will form on earth also as they form on the moon also. The earth is having more area to offer to an asteroid or meteor to hit and they will form caters. But they are getting eliminated on the earth but it is not the case on the moon.
    Three processes were described in the literature which will make the earth free from caters. They are
    1. Erosion: The planet earth is having weather, water, and plants. These will make the ground to wear down erosion. This can break a crater. But the moon is not having weather, water and plants. So there is no erosion and craters will be there permanently.
    2. Tectonics: These are processes which will make our earth to form new rocks and get the old rocks vanished. It will be happening around millions of years. But there is no process called Tectonics. So there is no chance for the craters to get vanished.
    3. Volcanism: Volcanic flows will cover up impact craters. The Moon had a large volcanic flow. But no volcanism for more three billion years. That is why craters are there on the moon.

    always confident

  • #705626
    Yes, all of you are correct with your explanations regarding why there are plentiful of craters in the moon, whereas it is not the same here on earth. Just as all of you have mentioned earth too has been bashed by asteroids and meteors of all sizes. One such big asteroid must have been the cause of the annihilation of the dinosaurs on earth. But the ones which are smaller they simply get annihilated by the earth's atmosphere. For this, we have to be thankful that we have an atmosphere. But those who might venture to colonize the moon will not be so fortunate. After all, even a shower of micro dust particles in the moon will be sufficient to tear us into pieces, as they will be striking at a speed much faster than bullets. Staying above the surface of the moon will be thus dangerous. If at all mankind will like to colonize the moon sometime in the future, either it will have to create an unpenetrable glass dome or will have to live underground in caves and tunnels.
    Patience and perseverance pays

  • #705671
    You have summarised it very nicely. I just want to add that the scientist pursue many research projects on the study of these meteorites to find out the elements and other compounds in them and sometimes find some interesting information. This also gives an opportunity to study the rock material coming from outer space to Earth and some of that could be much older than Earth giving opportunity for doing research to find the age of the universe. So, study of these bodies which make to reach Earth in spite of partially burning in the atmosphere help in finding much valuable scientific data.

    Knowledge is power.

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