LaurieAG

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About LaurieAG

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    Baryon
  • Birthday 11/09/1959

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    Applied Science
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  1. Hello Hypervalent_iodine,

    I owe you and the moderators an apology as I did a bit of experimenting last night and it looks like the issue is to do with a teething problem after the latest upgrade, as I pasted text with URL tags in it.

    I came across something similar around 16 years ago where I fixed one part of a multi use function only to have another issue pop up and vs a vs, just like an unruly seesaw. Considering how much effort has gone into sorting out these issues it's probably easier for the developers to just copy the function so that the preview and post options are separated, and they can tinker with each side without upsetting the other.

    Regards,

    Laurie

  2. Thanks Strange. If you copy the links and paste them into a new tab in your browser they will work.
  3. Hi Hypervalent_iodine,

    The other 3 science forums below that I posted this on didn't get linked back to the OP, especially as I tested all the links before I posted on all 4 sites. 

    Can you please restore the correct links in the OP on the following thread and ask the moderators not to change them. You can remove my reply after the links are restored if you like. 

    https://www.physicsforums.com/threads/basic-rule-for-atmospheric-reentry-of-glider-class-vehicles.944162/

    https://forum.cosmoquest.org/showthread.php?168356-Basic-rule-for-the-Atmospheric-Reentry-Time-of-non-powered-Glider-Class-vehicles

    http://www.scienceforums.com/topic/24218-near-earth-objects/page-13#entry355340

    Regards.

    1. hypervalent_iodine

      hypervalent_iodine

      Sorry, I only just saw this. It is better that you report these things or PM staff in future, so they aren't missed. 3

  4. Gee, the other 3 science forums I posted this on didn't get linked back to the OP, especially as I tested all the links before I posted on all 4 sites. I will make an official complaint if the correct links are not restored pronto! https://www.physicsforums.com/threads/basic-rule-for-atmospheric-reentry-of-glider-class-vehicles.944162/ https://forum.cosmoquest.org/showthread.php?168356-Basic-rule-for-the-Atmospheric-Reentry-Time-of-non-powered-Glider-Class-vehicles http://www.scienceforums.com/topic/24218-near-earth-objects/page-13#entry355340
  5. The Chinese Space Station, Tiangong 1, looks very much like a glider i.e. a bit like the US Space Shuttle (solar panels are made of similar materials to Space Shuttle tiles with much less friction), as the German radar images show in the link below, so it most likely wasn't tumbling but yawing from left to right and pitching and rolling just like a glider would, as it comes down to land. https://www.space.com/40089-china-space-station-tiangong-1-radar-images.html Here's a basic summary of how to project the reentry time of non powered Glider Class reentry vehicles, similar to Tiangong 1, as it might prove useful in the future. It's probably a little bit easier to look at rough approximates, as I never managed to find out how the US Strategic Command, or anybody else for that matter, calculated their Altitude of Nominal Burst (ANB). The ANB's used below are those provided by Satview.org, so here's the basic methodology. The basic rule of thumb is that when the natural descent becomes a Pythagorean right triangle with a ratio of 3:4:5 over 8 days. i.e. it drops 6km over 8 days, the time to atmospheric reentry is approximately 1 kilometre per day until the average ANB (over those 8 days) is reached plus an adjustment factor. I made rough plots and a projection on the link below on March 1, and wasn't sure how recent the data was as the Satview.org UTC timers (and the ANB) were all over the place for most of the reentry, so the end figure I used was 252.5 - 220.25 = 32.25 days - an adjustment from my last plot (i.e. 09:00 UTC March 1), because I didn't know how accurate the timing/altitude was. http://www.scienceforums.com/topic/24218-near-earth-objects/page-11#entry354689 Note that my figures don't actually reflect the eventual altitude of atmospheric reentry (ANB), they just indicate the time of atmospheric reentry based on the last data point, that satisfies the criteria in bold, and the average ANB projections over the previous 8 days. Even without the timing adjustment this projection was much more accurate than the forecasts by the US Strategic Command and the European Space Agency (ESA) for most of March. The eventual atmospheric reentry time given by the US Strategic Command via Satview.org was April 2, 2018 at 00:16 +/- 1 minute UTC (below) and China Manned Space give the reentry altitude as approximately 132.75 km (below). http://www.satview.org/?sat_id=37820U http://en.cmse.gov.cn/col/col1763/index.html
  6. Our bb models based on gravity can't measure anything outside the boundary of the sphere we measure it in. That doesn't actually mean that there is nothing there, it's just that with our current physics we just don't really know anything about it and can't measure it so we say that it doesn't exist and create something that we can't define under the same physics but can measure to explain our ignorance. After all, it's much easier to search for eternity for something that doesn't exist than to actually hypothesise something that we cannot measure. One thing we do know is that the ratio's of our total calculated universal matter divided by our (visible matter times 2), in both the Planck and WMAP data and under the LambdaCDM model, comes out to Pi +/- 1.1% but it's so much easier to call this numerology, stick our heads in the sand and refuse to explain it, because we know better (when we don't). https://en.wikipedia.org/wiki/Numerology#To_describe_questionable_concepts_based_on_possibly_coincidental_numerical_patterns
  7. White collar work Vs Blue collar work

    Probably because they are professionals who tell people what they need to hear as opposed to what they want to hear, from where I come from anyway.
  8. Bernie Sanders & Russia election interference

    Isn't this just another form of Astroturfing which just means you are being "hoist by your own petard"? https://www.businessinsider.com.au/astroturfing-grassroots-movements-2011-9#exxon-mobil-was-behind-a-youtube-video-spoofing-al-gores-an-inconvenient-truth-1
  9. The appearance of blue eyes and dark skin in northern genetics has occurred more than once in the past 10,000 years although we don't have any records of the existence of major civilizations for more than 8,000 years ago. One more recent example is around a thousand years ago where children of scandinavians employed in the Varangian guard received blue eyes from their fathers and dark skin from their mothers. That's interesting as a similar process would require a currently unknown northern civilisation.
  10. APolitical Correctness, a scientific approach

    I never said anything like that at all. If the only things you can come up with are straw man arguments then this thread should be closed, and future readers can make up their own minds.
  11. APolitical Correctness, a scientific approach

    I was talking to a guy with a phd in chemistry this afternoon and he said that they would have extreme difficulty doing useful science if they could not discriminate against those results that were from non female females or non male males (or non identical identical twins, and throw them in the bin). It would be politically correct to not make the correct distinction and apolitically correct, or if you like not politically correct, to make the correct scientific distinction.
  12. APolitical Correctness, a scientific approach

    Identical twins are not in a political category like male or female where you don't have to genetically or physically be a male or a female to actually consider yourself to be a male or a female. apolitical eɪpəˈlɪtɪk(ə)l/ adjective not interested or involved in politics. "he took an apolitical stance" correctness kəˈrɛktnəs/ noun the quality or state of being free from error; accuracy. "there was evidence to support the correctness of the identification"
  13. APolitical Correctness, a scientific approach

    It's interesting to see from the responses who is PC on this forum.
  14. Dark Matter or Dark Force

    Why bother with indirect things when you can deal with the problem directly? According to the latest PLANCK data total universal mass = 4.82% normal matter + 25.8% dark matter = 30.62% and the ratio between total calculated universal matter and total visible universal matter = 2*Pi +/- 1.1%. It's easier to define our total universal matter as a polar or transformed variant of our ordinary matter (that puts the galactic rotation problem to bed as well) than continuing to believe the difference is something that cannot be clearly identified with our current physics.