Janus

Just for fun, if you wanted the tidal influence to equal that now exerted by the Moon, you'd have to increase the orbit by a factor of 30, putting it somewhere in between the orbits of Himalia and Lysithea, with an orbital period of over 250 days.

If Earth orbited around Jupiter at the moon's present distance from Earth, then it would orbit Jupiter once every 1.43 days. Assuming it starts with its present rotation rate, then Jupiter would cross the sky every 3.33 days. However, it would be undergoing nearly 27,000 times the tidal forces it does now, and this would likely drive a great deal of geological heating and tidal braking, and tidal locking would be the eventual outcome. It wouldn't be a pleasant place to live.

Assuming a 100% efficient "Photon drive", you would need a fuel to mass ratio of 886 to 1 in order to just do a trip to Vega (27ly), stopping there. (this doesn't include a return trip) The center of the galaxy would require one of 955,000 to 1, and the Andromeda galaxy 4.2e9 to 1. Since 100% efficiency is not in the cards, in reality, these would be significantly higher .

Bush is likely adhering to Reagan's 11th commandment: "Thou shalt not speak ill of any fellow Republican." Since his father was Reagan's VP, this was likely strongly impressed on him, and a hard habit to break.

It didn't seem to help him the last time, as he received no bump in the polls afterward. Maybe, after all his whining about "witch hunts" concerning his recent legal problems, he's used that well too often, and it's gone dry.

Thanks for the concern, But I'm a good 500 mi from Jasper, and on the other side of the continental divide.

TIL that children's tendency to dislike vegetables may actually be an evolutionary advantage. Vegetables tend to be somewhat bitter, but so are poisons. Children have more taste buds than adults, since we lose them as we age, which makes them more sensitive to this bitter taste. With their smaller size, it takes a smaller amount of poison to be lethal, so a greater tendency to spit out bitter foods decreases the chances of ingesting enough toxins to be fatal if they put the wrong thing into their mouth.

We'll be rooting for England in our household, as my wife has English ancestry on her dad's side.

While the Sun relies on its gravity to maintain its fusion reaction, this is not the only way it could be done. Fusion research is based on designs that used other methods, like high powered lasers to compress deutrium to the point that it undergoes fusion. This has worked to a degree, by initiating the fusion reaction, but the hurtle is getting things to the point where the energy produced is enough to not only power the lasers, but also to have a sufficient excess to make a practical power plant.

Trace out the path of the end of the shadow on different dates of the year. With the flat Earth model, with the Sun circling over the disk and shifting between the two Tropics, you would always get arcs of concentric circles. With the globe model, you get series of hyperbolas starting with a maximum curve in one direction for one Solstice, to a maximum curve in the opposite direction on the other Solstice, and which flatten out to straight lines on the dates of the Equinoxes

And even in that election, he lost the popular vote.

One of the producers of The Apprentice has starting talking since the NDA he signed has lapsed. He said that it took hours of editing to make Trump seem sharp in that show. They would often resort to putting him into a recording booth to read lines from a script. They would then use those recordings in the shots when the camera was on a contestant and not Trump himself.

I've witnessed this type of thing before. Years ago, I had a boss that was obsessed with security. Everything had be be locked up and secured against theft at all times. He was later dismissed for misappropriation of funds. He was dishonest, and assumed that everyone else was also. Trump displayed this behavior a while back when he admonished Taylor Swift for not supporting him, claiming that his policies helped her financially. In his mind, this should be enough, and the idea that Swift might find other issues rather than her own personal wealth more important was inconceivable to him.

The light clock experiment with 2 light clocks( red and blue) starting at the same point: The expanding circles highlight how the the light pulses travel at c. The same experiment, but now, we are "riding along" the blue light clock. From the inertial frame where the red clock is stationary, the blue clock ticks slower, and the from the inertial frame where the blue clock is stationary, the red clock ticks slower. Keep in mind this is the same scenario, just viewed from different inertial frames of reference.

It reminds me of one of "sovereign citizen" videos where they show up in court, ignore everything the judge says, and just keep repeating the same phrases from their "script" over and over again.

This is nothing but a bunch of half-baked ideas based on misconceptions, and all it shows is that you don't have the faintest understanding of Relativity.

The issue with time dilation descriptions like the one with the train and embankment is that they often miss a critical point, since they generally focus on the embankment observer alone. So let's consider both observers. We start with two colocated light clocks, 1 stationary to our reference frame and one in motion. In these animations, the yellow dot is the pulse of light bouncing between the mirrors. The expanding circles are radiating outward at c, and act as reference showing that each pulse is moving at c relative to the frame of reference. Animation 1 is the from the frame in which the red clock is stationary. As can be seen, the red light clock ticks faster than the blue clock. If, for instance, the round trip for the red clock takes 1 micro second, it takes longer than that for the blue clock to complete one round trip. But what if there were someone "riding along" with the Blue clock? What would be happening according to them? This is what Animation 2 shows Since light travels at c in all inertial reference frames, In this frame, it is the Blue clock that takes 1 microsecond per round trip, and the red clock that ticks slower. Keep in mind, we have changed nothing from the previous animation other than switching observers. And there is no reason to prefer Red's perspective of events over Blue's or vice-versa. Both are equally valid. The two frames just measure time differently. This is the essence of Relativity.

Someone else fact-checked this, and determined it was actually only 2 (of the 7 in the US). So maybe the world only has a 2 in 7 chance of ending tomorrow.

I also heard about at least one hotel in the path of totality pulling the same stunt that some pulled during the last eclipse, canceling reservations that had been made well in advance once they realized how much people were willing to pay for a place to stay in the eclipse path. In this particular case, it was a travel agency that had been booking "Eclipse packages", and had been making arrangements with this hotel starting 2 years ago. Suddenly, and just recently, the hotel informed them that they were canceling the contract. I missed the '79 eclipse due to clouds(even though I lived in the path of totality), and almost missed the one in '17 due to fog/low clouds(we had a lucky encounter with a sanitation worker who told us that by driving up a certain street and up a hill, we could get a clear view.)

Point 1 is wrong. Time dilation is not due to a change in difference between emitter and receiver. Such a difference change produces a Doppler shift, which is a separate effect. Time dilation is where two reference frames measure different time intervals between two events. So, for example, if you had two emitter/receiver setups. Each with a constant and equal distance between each respective pair, and these two setups were in motion, Then an observer at rest with respect to either of the setups would note that the time intervals between transmission and reception would differ between the setups. Point 2 is also incorrect. In such a mechanism, the purpose of the wound spring to to counter losses due to friction. It doesn't take any force to keep something moving at a fixed angular speed. If you were to remove friction from the example, the hand, once moving, would just continue to rotate on its own without any further input of force. This would not change due to the overall motion of the mechanism. The clock hand would be measured as moving slower by someone that the mechanism is moving with respect to, but this is due to their measuring time intervals differently, and not due to some mechanical effect acting on the mechanism. Point 3 is, again, incorrect. c is the "speed limit" in the universe because it is an invariant speed. If something ( like light) is moving at c, then everyone measures the light as moving at c with respect to themselves, regardless of the relative velocity differences between those doing the measuring the light. A universal speed limit equal to this invariant speed automatically follows due to its mere existence.

Direct sunlight ~100,000 lux 0.1% of that 100 lux, which is equivalent to an heavily overcast day, and brighter than that of the hallway lighting of a typical office building. A moonless clear night is ~0.002 lux

Ants can do this because of something called the square-cube law. When you increase the size of something by a given factor you increase its surface area and the area of its cross-section by that factor squared, and it volume (thus its mass) by that factor cubed. The strength of limbs are dependent on the area of their cross-section. Which, as the size increases increases at a slower rate than the mass/weight of the animal. Increase an ant to the size of a man, and it wouldn't even be able to support its own weight. Conversely, shrink a man down to the size of an ant, and they'd put a ant to shame in terms of strength. So in terms of higher gravity, this just means that smaller animals would generally fare better.

TIL that I was born on a continental divide. I was born in the Mesabi range in MN, which I learned is part of the Laurentian continental divide.( a dividing line between which way water flows to the ocean.) It is one of 6 in North America: Great, Arctic, St. Lawrence, Laurentian, Eastern, and Great Basin. In addition, where I lived was also where the St. Lawrence divide meets up with the Laurentian divide.

Approval ratings in today's political climate are a bit meaningless. How many disapprove because they think he's "too far to the Left?" and how many because they think he's "too far to the Right" How many give him a poor rating based on just one single issue? etc.

Again, F=ma merely gives a relationship between force, mass, and acceleration. It does not have anything to do with push or pull. It gives the magnitude of the force required, and isn't concerned as to the nature of, or how this force is provided. Here is another equation : F= mv2/r It tells you how much force is needed to constrain a mass to moving in a circle with a radius of r if it has a mass of m and has a speed of v. It makes no difference as to how that force is applied. It can be by a rope anchored at the center of the circle, a rocket engine mounted on the mass applying inward thrust, by the gravity of a central mass, or by the friction between a car's tires and the road.