Recent content by Janus

  1. Janus

    Undergrad Another Time Dilation Question

    He would not physically "see" a pancaked planet, that is something inferred by applying Relativity. What he would physically see is blue-shifted light coming from the planet and the planet appearing to approach at a speed greater than c. Now, he will understand that the planet isn't physically...
  2. Janus

    Today I Learned

    Not quite that old, but it was a bit small, just a two-seater. https://en.wikipedia.org/wiki/Piper_PA-38_Tomahawk#/media/File:Piper_PA-38_Tomahawk_3-view_line_drawing.svg The flight instruments were basic and not much in the way of avionics. ( basically a VOR and a Radio) No headset either, you...
  3. Janus

    Today I Learned

    TIL that the Piper PA-38 Tomahawk, the plane that I took my initial flight lessons and solos in ( over 40 decades ago), is, on two separate lists, considered one of the ten most dangerous small single engine planes to fly.( to the point that it was sometimes referred to as the "Traumahawk".)...
  4. Janus

    Are these rabbit pellets???

    Definitely look like rabbit pellets. We raised a few rabbits when I was in High school, and they look very familiar. If you have a garden or flower patch, they make excellent fertilizer.
  5. Janus

    How effective is nuclear propulsion?

    Given that this type of engine have about twice the exhaust velocity of the Shuttle's main engines, then if you were able to substitute, then about twice as fast as given above.
  6. Janus

    How effective is nuclear propulsion?

    To reach Alpha Centauri in 100 years, you would need to reach a speed of least 0.043 c (12900000 meters/sec) Given the exhaust velocity of even the main shuttle engines, this works out to e^2931 kg of fuel per kg of payload mass.( here e is Euler's number) This is more mass than contained by the...
  7. Janus

    How effective is nuclear propulsion?

    For simplicity's sake, we will assume a shuttle in orbit with a fully fueled external tank. IOW, we won't factor in the Solid fuel boosters. The Shuttle itself has a mass of 75,000 kg. The external tank has a empty mass of 35,500 kg and holds 718,500 kg of fuel and oxidizer. This puts the...
  8. Janus

    An "Untranslatable" Word?

    While Finnish does have words for "yes" and "no" It also does something similar. So for example, The question Maalaatko taulua?" ( Are you painting a picture?) is answered with "Maalaan"( I am painting)
  9. Janus

    An "Untranslatable" Word?

    The word "Sisu" in Finnish comes to mind. One attempt that tries to define it goes like this " Extraordinary determination, courage and resoluteness in the face of extreme adversity. An action mindset which enables individuals to see beyond their present limitations and into what might be...
  10. Janus

    Convert Circular motion into figure-8 shaped loop

    Of course, now you inspired me to do a more physics engine driven example. In this animation, the boxes actually constrain the cylinder using rigid body physic, then the path is traced out using geometry nodes. I didn't do a figure eight, but just basically gave the boxes some random motions...
  11. Janus

    Convert Circular motion into figure-8 shaped loop

    Since the original animation was just to show the basic idea, I didn't include those types of restraints as it would be simple to do something like this instead to keep the bars oriented.
  12. Janus

    Convert Circular motion into figure-8 shaped loop

    The top one was done using armatures, which act like a chain of bones, in this case, 2 bones. The base of the chain is parented to the smaller gear so it follows it as it rotates. the other end of the chain is parented to an "empty" (essentially an invisible placeholder for an object). and that...
  13. Janus

    Undergrad Light clock treating horizontal and vertical motion differently?

    While a postulate is not a fact, it we can make predictions as what would happen if it were true. This, in turn allows us to devise real life experiment to test whether these predictions hold, and whether or not the postulate is valid. To date, all real life observations align with this...
  14. Janus

    Today I Learned

    A problem that arises when is comes to languages that are not native to you is that, not only do they have sounds that can be hard to properly form, they are sometimes even hard for your ear to distinguish, so you even hear it as the nearest equivalent in your language.
  15. Janus

    Convert Circular motion into figure-8 shaped loop

    Yes, done with Blender.