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Posts posted by Steel

  1. 6 minutes ago, kerbiloid said:

    But if presume that both answers are correct, and that it means that any thing has a counterpart with the parameters of the opposite sign, then we get the existence of two absolutely similar sides of the Universe, with total mass, energy, impulse, and so on by definition equal to zero.

    This is why some physicists think parts of theoretical physics are loosing their usefulness.

    People spend time making lots of very clever theories by looking only at the mathematics, but do not worry whether or not they actually relate to our universe.

  2. 13 hours ago, kerbiloid said:

    Here the mass is not essential, as the relativistic factor effects also length, time and so on.

    Just why do we exclude one of the roots intuitively, on a whim. Why do we just say "no negative root". Maybe there are both.

    As far as I understand it, the negative root is still valid from a purely theoretical standpoint (as it is in many equations) however we have no evidence for negative masses, and many cosmological theories do not allow for it, so the root is ignored.

  3. 3 hours ago, Gargamel said:

    Given a vacuum chamber on earth, so no air resistance.   You place a portal (from the game) on the ceiling, and one on the floor.  An object is then dropped into the floor portal, and falls through the upper one back into the lower one.   We've all done this in the game, falling for ever.   

    Given that gravity will be imparting it's acceleration for an infinite length of time, would the object ever reach the speed of light?  Could it surpass it since the energy is being 'supplied' by an outside source? 

    No. It doesn't matter what is providing the acceleration (even if it is a massive, physics breaking, free energy machine) you cannot accelerate a massive object to, or past, the speed of light.

  4. Short answer: no.

    Simplifying it massively, for heat to be transferred between two particles, you require energy to be transferred between the two (i.e one particle loses energy, the other gains it). Just because two particles have their states entangled doesn't mean that energy is transferred between the two, so it's not a mechanism that can be used to transfer heat.

    Also on a side note, the concept of "heat" at the level of quantum particles doesn't really mean very much, heat is very much a macroscopic phenomenon.

  5. It's interesting work, and the results are notable. However, the paper is far from extensive and a simulation of 50,000 particles is not much to shout about, so I'd stop well short of jumping to any conclusions without further, more detailed, corroborating work.

    The biggest hangup for me is that his model is for a "continuously-created negative mass substance". There's something about requiring a substance that has to be constantly created in order for it's effects not to be diluted by spacetime expansion that just doesn't feel right to me - completely non-scientific, I know.

  6. 13 minutes ago, Ultimate Steve said:

    Title gore for sure, but this is a bit complex...

    I recently had the idea to write a story about a system of binary planets, both with intelligent life at similar stages of progression with different strengths. In one sudden event the civilizations would be made aware of each other and they'd attempt to explore space in some way, etc...

    What I'm currently struggling with is how to make the sudden reveal seem realistic. The best idea I have right now is to make one of the planets extremely cloudy, so very little light makes it ot the surface, so not even the star will be distinguishable most of the time. But then the clouds would have to somehow disappear without altering the atmospheric composition. And the life on the planet would have to adapt to much more solar heating and a bunch of other things.

    I have one idea to eliminate the need for a reveal entirely but I'm not sure I want to go for it... Any ideas on if or how this would be possible?

    My idea would be to make one of them an underground civilisation that rarely went above ground. Don't know whether that works in with whatever story you have so far, but that's my two cents.

  7. 2 hours ago, Aquaticfantastic said:

    Have you read Andy Weir's Artemis? set in a 'city' on the moon.

    Whilst not as realistic as The Martian still a great read!

    I don't think Artemis and The Martian have much in common other than their author in all honesty. I loved The Martian, but Artemis didn't hit any of the same good points for me personally.


    I'd heartily second the earlier recommendation of KSR's Mars Trilogy. I've only read Red Mars, but it's hands down amazing and I've already lined up the other two.

  8. 20 minutes ago, BillKerman1234 said:

    Ok, so I’ve been thinking, and from what I can see, this is what we need to do:

    1) figure out what type of satterlite our payload is gonna be

    2) figure out the cost and mass of the payload

    3) figure out what type of rocket propulsion system we’re going to use

    4) do the math on the size, shape, and mass of the launcher

    5) design the basic concept of the launch vehicle around the required propulsion system and payload

    6) use ksp realism overhaul to simulate it

    7) 3D model the vehicle and do cfd on it

    8) get me to persuade some guys I know at the British Interplanetary Society to let me use their proper rocket simulation software 

    9) 3D model the vehicle in much more detail 

    10) reach out to university’s and organisations to sponsor us

    11) build it


    ...sound simple enough! *sarcastic facial expression*

    Just my quick thoughts:

    If this gets to a serious point of asking for money from people, people will expect serious documentation. There are 1000's of people who have ideas for low cost rockets, but very few will have detailed sourcing plans, every single part designed, costed and sourced and a genuine plan a out how they'll build and fly a rocket. All of that stuff will be needed before anyone will even have the conversation about money.

    One other thing. With a project so complex, you have to factor in the fact that there will be a lot of testing involved, some of it destructive. I can almost guarantee the first attempt (as well as the second, third and maybe fourth) at designing and building some parts will fail, and that all needs to be factored into the project.

  9. 2 hours ago, BillKerman1234 said:

    Another question: does anyone know the mixture rato of jellied petrol / htp? I’m trying to calculate how big the rocket will need to be, but I need the volume of fuel & oxidiser, and in order to calculate that I need the mixture ratio.

    For now I’ll assume it’s 1:1

    7:1 for H2O2/RP-1

    Also, why jellied? 

  10. 1 hour ago, Diche Bach said:

    Uhh . . . given that nothing escapes a black hole, how could one consider it to be an "energy source?"

    ADDIT: and going back to the question to which you responded "What is the most efficient way to use the sun?"

    What about photosynthesis? Is anything actually "more efficient" than that?

    Photosynthesis is horribly inefficient, I think man-made solar panels are better by a factor of 10 or so.