On April 21, 2014, the Hubble telescope captured what looks like a black hole in Jupiter’s Great Red Spot — but really, it’s the shadow of the Jovian moon Ganymede. (Source)
If you held out your thumb, every second about 65 billion neutrinos will pass through it. Besides photons, neutrinos are the most abundant particle in the universe, and by far the most unique.
The existence of the neutrino was first theorized by Wolfgang Pauli, after noticing how energy didn’t seem to be conserved in beta decay. He believed that the missing energy was being carried away by some “invisible” particle. He would later say “I have done a terrible thing, I have postulated a particle that cannot be detected.”
Although elusive, neutrinos can be detected, but it requires sensitive, and often massive detectors. After finding that neutrinos came in three types: electron, muon, and tau, a problem seemed to emerge. Electron neutrinos are created all the time in the Sun, as a by-product of nuclear fusion, but they would always find only a third of the total number of electron neutrinos they were expecting. So, where did the missing neutrinos go?
It turns out, neutrinos actually oscillate back and forth between the three different types. So, by the time the neutrinos from the Sun had reached Earth, two thirds of them have turned into muon and tau neutrinos. This discovery was especially surprising, since everyone thought neutrinos had no mass, like the photon. The fact that neutrinos could change in-flight implied that they could experience time, and due to special relativity, this means they must have mass.
While that mystery has been solved, we still have plenty to learn from these strange particles. Exactly how much do they weigh? Although we know they must have mass, they are so light, we can’t tell how much. Since they have no electric charge, is a neutrino its own anti-particle? Is there more than just three types of neutrinos? Answering these could help us uncover some of the biggest mysteries in physics today.
1705 Halley Documents Comet British astronomer Edmund Halley predicted the return of the comet that we now call Halley’s comet. He documented historic comet sightings and found patterns that led him to theorize that comets, which until then were considered baffling and even potentially dangerous because of their irregularity, actually had calculated orbits around the sun and would return periodically. He believed that the comets witnessed in 1531, 1607, and 1682 were actually the same comet and predicted it would return in 1758. Even though Halley died in 1742 the comet arrived on schedule and later became known as Halley’s Comet.
Need more astro-stuff? Go to www.astrotidbits.com and see what is there.
Sorry, Tumblr, but Seth found his new favorite social network to reach fans: Ham radio.
The transit of Mercury, left, in front of the Sun, photographed from St.Petersburg, Russia on May 9th 2016. The photo was taken through a hydrogen-alpha (H-alpha) narrow spectrum solar telescope that permits examination of the sun’s protuberances and shows the surface activity. Credit: AP/Dmitri Lovetsky
I'm curious about the physics of bottle rockets. In the novel I'm writing, my characters use bottle rockets as weapons. They tape sharpened sticks to the rockets and use them as projectile spears. What would be the velocity of a bottle rocket with a stick taped to it? What kind of damage would it inflict? Love your blog! Thank you!
The final velocity depends on a lot of variables, like the trajectory, weight, fuel being used, burn rate of the fuel, size of the bottle, etc. However, you can be assured that they can be harmful and with the right pointy sticks, they can be deadly.
Here’s one example:
Good luck with your novel!
FLAIR FLIGHT A contrast-enhanced image produced from the Hubble images of comet ISON taken April 23, 2013 reveals the subtle structure in the inner coma of the comet; the coma decreases in brightness proportionally to the distance from the nucleus. Comet ISON, thought to have travelled from the Oort Cloud surrounding our solar system beginning a million years ago, will make its closest approach to the Sun on Thursday. (Photo: NASA via AP / The Telegraph)
Aerospace Engineering Magazine April 1962