It is impossible to measure the speed of light, and it has been impossible since 1983. No, the behavior of light didn’t suddenly change in 1983. What changed was the way we define the length of a meter.
Here and There
When Isaac Newton proposed his universal law of gravity, he was actually making a rather bold claim, specifically that the distant stars and planets are governed by the same physical laws that govern the Earth. This was a radical split from the traditional Aristotelian view that the heavens were fundamentally different from terrestrial physics.
Coin Toss
Suppose you were given one million dollar coins. Sure, you could spend it on something frivolous like paying off your house or your college loan, but you could also use those million coins to play a game related to quantum physics.
Massive Issues
We all know that many objects (atoms, cats, us) have mass. What you probably don’t know is that there are multiple different types of mass, and this has real physical (and astrophysical) consequences.
Balancing Act
Gravitational potential is a nice mathematical way to describe the effects of gravity on an object. You can get an idea of how gravitational potential is related to gravity by imaging a ball on field of rolling hills.
Engineering Problems
To that end, suppose on our rocket we had a perfectly efficient engine that converted 100% of the fuel into energy for the ship. This gives us an idea of just how much fuel we would need (at minimum).
Faster Than Light
There’s been a couple of questions about the possibility of traveling faster than light, so let’s explore that a bit today. The short answer to whether one can travel faster than light is no. The inertial speed of an object can never exceed the speed of light. This means if you measure the speed of an object passing you, it will always be less than the speed of light. The longer answer is “it’s complicated.”
And Yet it Moves
The central dispute between Galileo and the Church was whether Galileo could assert that the Earth really did move around the Sun (that is, as a scientific fact), or whether he should present the idea as merely a hypothesis. Church officials admitted that Galileo’s observations gave the appearance of moving around the Sun, but argued that appearances could be deceiving.
It Goes to Eleven
String theory proposes that there may be 11 dimensions to the universe, where we only see space and time. We couldn’t see these extra dimensions directly, but if they are there we could observe their effect on gravity.