Jump to content


Resident Experts
  • Content Count

  • Joined

  • Last visited

  • Days Won


Janus last won the day on April 6

Janus had the most liked content!

Community Reputation

1109 Glorious Leader


About Janus

  • Rank
  • Birthday August 28

Contact Methods

  • Website URL

Profile Information

  • Favorite Area of Science

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. First amendment of the US constitution: Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances. So the "right of Freedom of speech" pertains to the limits the US government has in this manner. It does not matter if the term "freedom of speech" already existed or who first coined it.
  2. The period over which tidal locking would occur is highly sensitive to the distance between the bodies, and varies by the distance to the power of 6. It is less dependent on the mass of the primary. The relationship ( assuming all else is equal) is T = a^6/M^2 So, if we take a very luminous red dwarf like Lacaille 8760 with a mass of 0.6 that of the Sun, and a Earth equivalent position in the habitable zone of 0.268AU, you get a time period for tidal locking of roughly 1/1000 of the the time it would take for the Earth to tidal lock to the Sun. For a smaller star like Proxima Cen
  3. That was the argument put forth by Galileo against the Aristotelian model of gravity that posited that heavier objects fell faster than lighter ones. It was not meant an argument against gravity itself, but against that particular model. He wasn't saying that gravity didn't exist, but that it didn't behave like Aristotle said it did. The model for gravity that replaced the old one didn't suffer from this feature.
  4. Of course no mention of the fact that if Mars had been at geostationary orbit distance from the Earth it would have pulled all the Earth's oceans into 6 km high tidal bulges.
  5. Growing up, we had a Siamese cat which had quite a reputation (It once chased a dog several times it size off our property.) Some people got to the point, that when they came over the first thing they would do was look around nervously and ask "Where's the cat"? And we had to warn people that if the cat came around don't reach down to pet her or your likely to pull your hand back bloodied. Now he wasn't that way with anyone in our household. (There were times when the cat would get under Mom's feet in the kitchen and she'd just pick her up with one hand and toss her out, and cat did no
  6. Right after I retired, I started taking morning walks for the exercise. My wife usually would join me, but a few weeks in she tweaked her back and couldn't, so I took my walks solo for a while. We had a cat at the time. Every day, when I got back from my morning walk, he come running, meowing, jump up onto the back of the sofa (which was near the front door), And wait for me to put my head down so he could give me a head bump. Then he'd jump down and go about his business. He'd already been fed, and my wife always fed him anyway, and It wasn't as if he had been lonely, as she had been
  7. My paternal Grandfather was 6 when the Civil war started (Born in Dec of 1854), though he didn't come to the US until 1883.
  8. You could set things up so that, from a given frame, the clocks started and ended "in sync", but this would require artificially adjusting the tick rate of the clocks. Thus you could get this as measured from the rest frame of the lower row of clocks. All the clocks in both rows remain in sync. However, when you transition to the rest frame of the upper row of clocks, you get this: The only moment when any two clocks read the same is when they are passing each other.
  9. Just after Thanksgiving, I finally updated my 7+ year old computer to a new "gaming"* computer. This has allowed me to upgrade Blender to the latest build, which has a number of new features and tools, as well as driving the render times down significantly. For example. One of the Star Trek matte paintings I tried to duplicate with Blender was of Stratos, the cloud city. While modeling the buildings wasn't that difficult, the clouds became problematic. In order to get the right look, you had to create a light scattering volume. This means that the render engine has to take into a
  10. There is a formula for this, it is the same one used to find synodic periods for planets etc. (for example, how long it takes between Earth and Mars passing each other as they orbit the Sun.) The formula is T = 1/(1/p1-1/p2) Where p1 id the time it takes for one plane to complete is orbit and p2 is the time for the other planet to complete is orbit. In this case we are not given times, so we will simply give B a complete circuit walking time of 1 time unit and thus A has a complete circuit walking time of 1/2 time unit. Thus for when they are walking in the same direction
  11. As swansot has already mentioned, it isn't quite that simple. There will be a gradient. Not only that, but there is the fact that the air in your ship will already be under pressure. If it is at 1 atm, this pressure is the same as caused by the weight of a column of air at constant sea level density which is 8.5 km tall.( at 1 g of gravity). So let's say your spaceship is 10 meters long and full of air at 1 atm. If you were to accelerate at 850 g, that air would be "pushed back" towards the rear of the ship. That 10 m column at 850g would act like a 8.5 km tall column at 1g. The
  12. Reminds me of the time when I was a kid in Northern Minn. My Dad was driving to work in the early AM. He began to feel cold, even though the car heater was going full blast, and was starting to wonder what had gone wrong with it, when the weather report came over the radio announcing that the present temperature in the small town he was passing through at the time was -50° F
  13. Maybe we should check between the sofa cushions.
  14. It's the second case. Elements that aren't stable, but relatively more stable than you would expect for such a heavy element.
  15. Janus

    Political Humor

    On the same topic: A reporter in a recent press conference asked whether Biden would hang a portrait of Trump in the White House ( something Trump refused to do for Obama) and along the same lines would he be inviting Obama to ceremony to finally hang his portrait. The answer was that no portraits hangings had been scheduled yet. But it struck me as a bit of a silly question. With everything on his plate right now, I doubt that Biden is giving much thought (or should be) to such purely ceremonial things.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.