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Thread: Astronomy

  1. #1156
    On the road, but not! Danik 2016's Avatar
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    Quote Originally Posted by Dreamwoven View Post
    I thought the IAU had changed its definition of dwarf planet by dropping the criterion of having "cleared their orbit (?)" (whatever that may mean), but it seems they have not, just widened the definition to include more "dwarf planets". Your last paragraph (above) accurately reflects the confusion around this whole question.
    Good links, DW.
    Thatīs whatīs makes current Astronomy so fascinating to me. A lot of set concepts have to be revised to explain the new discoveries.
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  2. #1157
    On the road, but not! Danik 2016's Avatar
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    This discussion probably will go on for a good time. I think the reason for it is that they have much more refined ways to observe the planets. The clutter in the neighborhood wasnīt taken into account before, because it hadnīt be observed.

    But one mustnīt worry. If they decide sometime in the future that the earth isnīt a planet, they will find another definition for it, I think. Even basic concepts change. See the discoveries of Galileo.
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  3. #1158
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    Good point, Danik.

    This is a quite different post, abut using nanosatellites to investigate the many smaller object (asteroids) in the asteroid belt.
    See this link:https://www.universetoday.com/137253...anosatellites/
    Last edited by Dreamwoven; 09-22-2017 at 11:37 AM. Reason: more information

  4. #1159
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    This website post looks at how it is planned to avoid collision with an asteroid, that is inevitable sooner or later:
    https://www.universetoday.com/137266...eroid-mission/

    Oh, and regarding Earth having "cleared its neighbourhood" (se the previous posts on this), NASA doesn't agree.

  5. #1160
    On the road, but not! Danik 2016's Avatar
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    Quote Originally Posted by Dreamwoven View Post
    Good point, Danik.

    This is a quite different post, abut using nanosatellites to investigate the many smaller object (asteroids) in the asteroid belt.
    See this link:https://www.universetoday.com/137253...anosatellites/
    Just read this post. Absolutely amazing. I think one can sum up several of all these discoveries in two or three important ones:
    1- The space between planets and stars is filled with smaller celestial objects or fragments, some of which might be put to scientific use.
    2-Celestial bodies present very different compositions and atmospheres.
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  6. #1161
    On the road, but not! Danik 2016's Avatar
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    I hope they succeed and Didi doesnīt fall on our heads. I donīt know if this huma messing around with the universe, which still is somewhat timid if you take into account its dimension, might start to influence the movement of the celestial bodies.
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  7. #1162
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    I doubt that, but you never know.

  8. #1163
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    I thought it was remarkable that some asteroids have their own moon and their own rings! And that some are made of sold nickel and solid iron:

    "The more that planetary astronomers study asteroids, they more they’re realizing just how varied and different they can be. Some, like 16 Psyche are made of solid nickel and iron, while others are made of rock. Some asteroids have been found with moons, rings, and some icy objects really blur the line between comet and asteroid. In order to truly understand their nature, it would take dozens or maybe hundreds of individual missions on the scale of Rosetta or New Horizons."

  9. #1164
    On the road, but not! Danik 2016's Avatar
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    About the constitution of our own planet:

    https://www.space.com/38235-earth-el...et-formed.html
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  10. #1165
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    The most interesting facts from this piece has to be the next exploration of Mars in 2018, to probe the planet's deep interior.

  11. #1166
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    I subscribed to Popular Astronomy] for a year and am re-reading it again. I am impressed by the large amount of material in it. I will select particularly interesting articles from the occasional more in-depth articles. The first will be about the moons of Mars.

  12. #1167
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    The Moons of Mars

    https://en.wikipedia.org/wiki/Moons_of_Mars

    I don't buy the suggestion that Earth has one moon, so Mars must have two! Nor that the Gulliver's Travels just guessed the detailed information he provides about these two moons. More likely that the ancient astronomers knew from their own observations.

    Phobos, Mars' larger moon, is slowly spiralling inwards towards the planet, estimated to disintegrate within the next 30-50 million years. Phobos has the inner orbit, Deimos is further out. There is a tremendous strain on Phobos. We know that our own Moon affects tides and Phobos is covered in fractures and has a large crater (Stickney Crater).

  13. #1168
    On the road, but not! Danik 2016's Avatar
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    I agree with you. As it isnīt known that writers Like Swift and Voltaire conducted any astronomical research of their own, they must needs have been influenced by the information of th period and a bit by their own imagination.
    Now we know that the universe is cluttered with bigger and smaller objects, they probably are going to find a lot of asteroids between Mars and its moons.
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  14. #1169
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    In March-April 2016 Popular Astronomy(p.18) published an article on the search for extraterrestrial life. Quoting Sir Arthur C Clarke (https://en.wikipedia.org/wiki/Arthur_C._Clarke): "Two possibilities exist: either we are alone in the universe, or we are not. Both are equally terrifying".

    Links to further reading:

    The best link is, I think, the first one, as it poses some interesting dilemmas:
    https://waitbutwhy.com/2014/05/fermi-paradox.html

    The other two I include here pose the usual dilemmas:

    https://www.space.com/25325-fermi-paradox.html
    https://sv.wikipedia.org/wiki/Fermis_paradox

    This website looks at the Search for ExtraTerrestrial Intelligence (SETI): https://seti.org

  15. #1170
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    There are some peculiar phenomena on our doorstep, one of which was identified by the Hubble Space Telescope:
    https://www.universetoday.com/137278...asteroid-belt/.

    This is a binary asteroid in the main asteroid belt between Mars and Jupiter.

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