How big would the sun be from the surface of Mercury and from the surface of Neptune? From the planet Neptune, the sun would look only slightly brighter than all of the other stars in the sky. You would be able to look at it directly without doing any damage to your eyes. From the […]
Where does space end? There is no way of knowing, but there is a horizon 46 billion light years away that we can’t see past. There are five different possibilities. That the universe is infinite. That the universe wraps in on itself. That there is no “outside” to the universe. That our universe is embedded
#303 Where does space end? Read More »
Where does space start? Technically, it starts at 100 km, but there are five different definitions. Space begins at the Kármán Line, which is 100 kilometers above sea level. There is obviously no sign that says, “Welcome to Space!”, so any line that shows the boundary of space has to be arbitrary. The reasoning behind
#302 Where does space start? Read More »
How big was the asteroid that killed the dinosaurs? It was probably 10 km across, but it could have been anywhere between 10 and 17 km. The asteroid that killed the dinosaurs hit Earth about 66 million years ago. Apparently, according to research, it was 66,043,000 (±11,000 years). The asteroid came down in the Yucatan
#298 How big was the asteroid that killed the dinosaurs? Read More »
How does a rocket engine work? Rocket engines work because of Newton’s third law of motion. Newton’s third law of motion states “to every action there is always opposed an equal reaction; or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.” Or, in other words, for
#293 How does a rocket engine work? Read More »
I learned this today. The Tunguska event was probably a meteor air burst that exploded over Eastern Siberia on June 30th, 1908. Today, as of writing, it is the 114th anniversary of the Tunguska event. Early in the morning of Tuesday, June 30th, 1908, there was a bluish light almost as bright as the sun,
#270 What was the Tunguska event? Read More »
I learned this today. The aurora borealis are green, purple, pink, and blue because those are the colors given off when the different elements in the atmosphere are heated up. The aurora borealis is caused by electrically charged particles from space hitting the magnetic field in the upper atmosphere at a very high speed. The
#264 Why are the aurora borealis those colors? Read More »
I learned this today. The energy from the photons in a laser beam can be used to propel a very light sail into space. A laser powered solar sail could let us look at the planets around the closest star to us. Laser propulsion has been suggested as the best way we have of reaching
#258 How can a laser power a solar sail? Read More »
I learned this today. Some planets have rings because they have captured debris, but that debris is too close to the planet to form into a moon. In our solar system, Saturn is obviously the most well-known planet with rings, but it is not the only one. Jupiter, Neptune, and Uranus also have ring systems.
#252 Why do some planets have rings? Read More »
I learned this today. Signals from intelligent life are so difficult to hear because of the sheer vastness of space and the fact that we change the technologies we use. It is possible to look at a distant planet and reason that it has intelligent life because of the gases that are coming off the
#239 Why are signals from intelligent life so hard to hear? Read More »
