1. We have added a Gift Upgrades feature that allows you to gift an account upgrade to another member, just in time for the holiday season. You can see the gift option when going to the Account Upgrades screen, or on any user profile screen.
    Dismiss Notice

The thread for space cadets!

Discussion in 'Off-Topic' started by hobbsyoyo, Sep 13, 2012.

  1. Cutlass

    Cutlass The Man Who Wasn't There.

    Joined:
    Jan 13, 2008
    Messages:
    46,554
    Location:
    US of A
    Discovery Of Most Powerful Supernova To Date

    Researchers have observed a super-luminous supernova explosion which is twice as powerful as the previous record holder.






    http://www.asianscientist.com/2016/01/in-the-lab/discovery-powerful-supernova-date/
     
  2. r16

    r16 not deity

    Joined:
    Nov 10, 2008
    Messages:
    6,203

    the people ı hang out out with tend to be oldies who toured NATO countries back in the day . One in particular , cap in hand , begged for Starfighter spares . And then supposedly it happened in the Netherlands , with they guy on the other side of the table couldn't keep it in . The guy naturally reminds of the day when those loyal Dutch Commies went into a Dutch airbase , stole a 'winder , rolled it in a carpet , sort broke the rear glass of their car , stuck the missile in , all 9 to 10 feet of it and drove out from the main gate . Before sending the thing , bit by bit , in parcels to Moscow by post . The guy also loved that .

    then months later first info started flowing ...

    the guy was throughly chewed by his superiors too .

    turned out it was a fluke . As a prospective employee of Aerospace business you will know there's no way the Russians could have obtained F/M series from the Phantoms in the rice paddies of North Vietnam and no way they could have been provided to Russia by a country that didn't yet have them .

    years passed , the chewed guy rose high . There was a war against the Serbs , over Kosova and stuff and the chewed guy lobbied hard to get an allotment . You will have noticed the USAF keeps all the air to air kills to itself , because they are so rare but the Dutch were set up for a killing of a Fulcrum .

    the chewed guy ended up chewed once again . There's no end to Turkish lies afterall .

    ı actually do not want SNC anywhere near my country , especially the entirely new and entirely Turkish Airliner they are peddling happens to ne something like Do-328 which ı used to like so much in the 1980s .
     

    Attached Files:

  3. hobbsyoyo

    hobbsyoyo Deity

    Joined:
    Jul 13, 2012
    Messages:
    25,338
    Luxembourg to support space mining

    Before everyone goes 'herpa derp LUXEMBOURG CAN INTO SPACE XD', note, as the article points out, that Luxembourg is actually one of the bigger players in the space industry.
     
  4. hobbsyoyo

    hobbsyoyo Deity

    Joined:
    Jul 13, 2012
    Messages:
    25,338
    Comets May Not Explain 'Alien Megastructure' Star's Strange Flickering After All
     
  5. hobbsyoyo

    hobbsyoyo Deity

    Joined:
    Jul 13, 2012
    Messages:
    25,338
    This is a cool idea and I've long thought that something like this is going to be the better near-term solution to affordable access to space between reusable rockets and a space elevator. Too bad they couldn't get the funding they needed to keep the doors open. :sad:
    Advanced space propulsion startup shuts down

     
  6. Berzerker

    Berzerker Deity

    Joined:
    Dec 30, 2000
    Messages:
    19,306
    Location:
    the golf course
    looks like a paper plane
     
  7. hobbsyoyo

    hobbsyoyo Deity

    Joined:
    Jul 13, 2012
    Messages:
    25,338
    In a sense it was, they never built it. :lol:

    The idea was that instead of burning fuel on board the ship, they would microwave energy to the ship which would use that energy to heat the fuel and expel it out of the nozzle, which is much more efficient than burning. An even more efficient set up would have been if they had been able to use the air of the atmosphere as the working fluid instead of bringing on board helium or hydrogen for that purpose. I suppose that would have been a next step in the program because that truly would have been massively efficient compared to even bringing along helium although much more difficult.
     
  8. Thorgalaeg

    Thorgalaeg Deity

    Joined:
    Jan 3, 2002
    Messages:
    5,108
    Location:
    Spain
    Why would using air be that harder? If not chemical reaction is needed anything could theoretically be used as propellant. We could even see working salami powered rockets finally!
     
  9. hobbsyoyo

    hobbsyoyo Deity

    Joined:
    Jul 13, 2012
    Messages:
    25,338
    Capturing and compressing the air while in flight would require the use of a complicated jet engine (minus the combustor which would be replaced by a complicated heat exchanger) that would add significantly to the total weight, complexity and drag of the aircraft. Even that would stop working around Mach 3-12, depending on which type of compressor system used (Turbojet/Turbofan, RAM or SCRAM). The air would be moving so fast (and the resulting shockwaves so hot) that it wouldn't be possible to 'scoop' the air with current technology.

    In other words, at best you could use an air intake of some sort to get up ~1/2 of orbital velocity before you'd be forced to switch to on-board stores of reaction mass. That would allow you to lift much bigger payloads or reduce overall mass of the vehicle for the same payload but at the expense of being much more complicated and with many more failure modes. Come to think of it, I think it would be a fair bet that any mass savings you could make in propellant would be washed out by the weight gain of the air scoop system. So we're really only talking about being able to lift a bigger payload with a bigger vehicle rather than reducing vehicle weight for a given payload. I.E. you can make a bigger, more efficient vehicle with the above system but not a smaller, more efficient vehicle. And since they were really trying to prove the concept rather than maximize all variables, they probably made the correct engineering trade-offs.

    But we're talking about what is possible with existing technology, where even the modest vehicle they tried to make is a stretch. In the future, who knows how much better of a vehicle they could make using all sorts of exotic thermodynamic cycles.

    Also, air definitely has much less potential (thermodynamically speaking) as a reaction mass than a pure gas such as Hydrogen or Helium.
     
  10. uppi

    uppi Deity

    Joined:
    Feb 2, 2007
    Messages:
    4,737
    Why is that? I am trying to think of a reason why the purity should matter, but I am coming up empty.
     
  11. Berzerker

    Berzerker Deity

    Joined:
    Dec 30, 2000
    Messages:
    19,306
    Location:
    the golf course
    What is that box-like structure below the tail?

    Are those colors for real and does anyone know how much space the image represents? Like is that a light year across?
     
  12. PlutonianEmpire

    PlutonianEmpire Socially Awkward Goofball

    Joined:
    Mar 11, 2004
    Messages:
    4,786
    Gender:
    Male
    Location:
    MinneSNOWta
    The colors are iust color codes used to represent specific elements (such as oxygen, hydrogen, etc). To the naked eye, it would look gray-ish. :)
     
  13. hobbsyoyo

    hobbsyoyo Deity

    Joined:
    Jul 13, 2012
    Messages:
    25,338
    It depends on they cycle they are using to ingest and then expel the reaction mass.

    If an air breathing system used some sort of pre-cooler to keep temperatures manageable for the compressor blades/wall, then you could end up with fractional distillation of the different components of air. (I think) I'm not sure how the Skylon system deals with this. Though upon reflection, they probably wouldn't need or necessarily want to bring inlet temperatures down to the boiling point of oxygen.

    If they are providing enough energy to the system to ionize the gas which they then expel of out some sort of electromagnetic nozzle, then you would have to account for the various energies that each species requires for ionization. (Highly doubtful they were going this route) I know this sounds highly dubious but at least theoretically, if they are beaming power to the craft, I don't see a reason why they couldn't just build a big enough power plant and transmitter to send it enough energy to do electric propulsion at very high thrust. Satellites that use electric propulsion are limited in their thrust by the amount of power they can generate; by decoupling the energy generation from the vehicle, you could at least theoretically scale up thrust quite dramatically.

    Finally (and most problematic in my opinion), while you can get a massive boost in efficiency by scooping up the air and expelling it, on a mass-unit basis, you are going to get a lower specific impulse from air as all of the components have different enthalpies that will average out to lower output thrust/specific impulse than a pure gas that you bring along (like say H2 or He). This, combined with the massive weight penalty and complexity penalty imposed by the scoop system itself will tend to balance out the advantages of scooping air for smaller systems. I think at a certain payload fraction, you would want to go with on-board gas. Above that point, a scoop system will make more sense.

    I mean, designs for nuclear thermal rockets use hydrogen for just this reason (much higher isp) despite extremely low propellant densities (and thus higher tank weights).
     
  14. Michkov

    Michkov Emperor

    Joined:
    Jul 5, 2010
    Messages:
    1,441
    Landing Gear door?
     
  15. uppi

    uppi Deity

    Joined:
    Feb 2, 2007
    Messages:
    4,737
    Thanks, hobbsyoyo.


    There have been pervasive rumors that Advanced LIGO has made a direct detection of a gravitational wave emitted by a merger of two black holes. Now they have scheduled a press conference for tomorrow. If true, distant objects in space can now be observed by the gravitational effect they have on spacetime here on earth. That is particularly interesting for black holes, because they do not emit much else that we could detect.
     
  16. dutchfire

    dutchfire Deity

    Joined:
    Jan 5, 2006
    Messages:
    14,106
    Location:
    -
    I've also been hearing increasingly open rumours and announcements of press conferences and seminars to discuss "first scientific results".
     
  17. hobbsyoyo

    hobbsyoyo Deity

    Joined:
    Jul 13, 2012
    Messages:
    25,338
    I'm reading the same rumors - the press is all but declaring they have found gravitational waves.

    Given how hard it has proven to detect any waves, how long do you think it will take to translate this experiment into a practical observation technique and how expensive do you think that effort will be? I would guess it would cost something like the LHC (and be of similar size) but I have no idea.
     
  18. trader/warrior

    trader/warrior Deity

    Joined:
    May 2, 2002
    Messages:
    2,257
    Location:
    More like Snoreway
    Watching the announcement stream right now, sounds like they are very confident about their findings and giving a lot of good laymans info and explanations. Their website seems to be overloaded right now so cant access the more detailed info yet.

    http://arstechnica.com/science/2016/02/upgraded-ligo-detectors-spot-gravitational-waves/
     
  19. Thorgalaeg

    Thorgalaeg Deity

    Joined:
    Jan 3, 2002
    Messages:
    5,108
    Location:
    Spain
    Well, it must be great to observe gravitational waves for first time and all, but it is not a breakout of physics or something because since the very moment we accept general relativity as a proven theory, we accrpt that: 1) gravity as any interaction propages not faster than light and 2) gravity blends spacetime. So, as i understand it, once the previous points are accepted gravity waves are an immediate consequence.
     
  20. red_elk

    red_elk Deity

    Joined:
    Mar 6, 2006
    Messages:
    13,139
    I think there is no such concept in physics. There are only theories which are proven to be wrong, and theories used as "working hypotheses" (not sure if correct English term).
     

Share This Page