(xkcd) – Randall Munroe:
It’s annoying when people are right by accident. …
Archive for the ‘Astrophysics’ Category
Supernova
2024-01-18(xkcd) – Randall Munroe:
Astronomers are a little cagey about exactly where the crossover point lies relative to the likelihood of devastating effects on the planet. …
How Vulnerable is Earth to a Solar Flare?
2022-12-10(Starts With A Bang!) – Ethan Siegel:
A solar flare from our Sun, which ejects matter out away from our parent star and into the Solar System, is a relatively typical event. However, a large-magnitude, energetic flare or a coronal mass ejection could do a whole lot of damage to our electrical and electronic infrastructure, costing trillions of dollars and potentially killing and displacing millions. …
Johannes Kepler
2022-11-05(Starts With A Bang!) – Ethan Siegel:
Johannes Kepler, whose life spanned from the late 1500s to the early 1600s, was perhaps most remarkable as a scientist for his discovery that planets move in ellipses around the Sun. Without the ability to throw out his own brilliant idea, he never could’ve gotten there. …
NASA to Crash $330m Spacecraft into Asteroid
2022-09-04(Guardian Science) – Robin McKie:
In a few weeks, NASA controllers will deliberately crash their $330m DART robot spacecraft into an asteroid to test if it can avert sci-fi fears of a catastrophic impact with Earth. The half-tonne probe will be travelling at more than four miles a second when it strikes its target, Dimorphos, and will be destroyed. …
The Hottest Stars
2022-08-23(Starts With A Bang!) – Ethan Siegel:
At their cores, stars can reach many millions or even billions of degrees. But even that doesn’t touch the hottest of them all. …
The highest stellar temperatures are achieved by Wolf-Rayet stars. …
The remnant cores of supernovae can form neutron stars: the hottest objects of all. …
X-raying the Entire Universe
2022-01-21(Starts With A Bang!) – Ethan Siegel:
The first supernova ever discovered through its X-rays has an enormously powerful engine at its core. It’s unlike anything ever seen. …
The Shortest Day Of The Year
2021-12-21(Forbes) – Chad Orzel:
The empirical fact of short winter days and long winter nights has been known essentially forever, and has driven enormous amounts of human activity including the construction of monuments like the passage tomb at Newgrange. The correct explanation of the phenomenon has only been understood for around 400 years, dating back to Johannes Kepler’s description of the orbits of the planets. …
On the solstices, the dates when one pole is most inclined toward the Sun, one hemisphere gets the longest possible day, the other the longest possible night. …
The Cosmic Speed Limit
2021-12-09(Starts With A Bang!) – Ethan Siegel:
As particles travel through the Universe, there’s a speed limit to how fast they’re allowed to go. No, not the speed of light: below it. …
Stick-in-the-Mud Astronomy
2021-12-08(Hayden Planetarium) – Neil deGrasse Tyson:
In modern times, various blends of high technology and clever thinking drive cosmic discovery. But suppose you had no technology. Suppose all you had in your laboratory was a stick. What’s there to learn? With patience and careful measurement, you and your stick can glean a ridiculous amount of information about our place in the cosmos. The stick’s material doesn’t matter. Neither does its length. Nor its color. It just has to be straight. …
The Andromeda-Milky Way-Collision Uncertainty
2021-11-29(Syfy Wire::Bad Astronomy) – Phil Plait:
We’re trying to measure the apparent motions of stars over time. Updated data from Gaia are expected in early 2022, and another release will occur after all five years of the nominal mission are processed, and are expected to be far more accurate than previous data.
So give astronomers a few more years and these numbers should tighten up. And then, hopefully, we’ll know for sure whether in an eon or four we’ll need to either fasten our seat belts for a cosmic collision or watch as Andromeda safely flies past us a million or two light years distant.
Patience. …
The Moon’s Atmosphere
2021-11-25(Starts With A Bang!) – Ethan Siegel:
We once thought the Moon was completely airless, but it turns out it has an atmosphere, after all. Even wilder: it has a tail of its own. …
How Elements are Made
2021-11-17(Starts With A Bang!) – Ethan Siegel:
There are over 100 known elements in the periodic table. These 8 ways of making them account for every one. …
Galaxies Beyond Our Reach
2021-10-26(Starts With A Bang!) – Ethan Siegel:
Distant galaxies, like those found in the Hercules galaxy cluster, are not only redshifted and receding away from us, but their apparent recession speed is accelerating. Many of the most distant galaxies in this image are receding from us at speeds that appear to exceed the speed of light. We will never be able to reach any of the ones presently located more than 18 billion light-years away. …
Neptune’s Discovery
2021-10-05(Starts With A Bang!) – Ethan Siegel:
From the 1600s, Kepler’s and Newton’s Laws described planetary motion precisely. In 1781, Uranus’s discovery gave us a new testing ground. After multiple decades, something was clearly amiss. Uranus initially moved quicker than predicted, then as anticipated, and finally, too slowly. A spectacular possible explanation arose: a massive, additional, outer planet. …
Gravitation, all on its own, can reveal what’s present in the cosmos like nothing else. …
Lucy’s Wild Ride to Jupiter’s Orbit
2021-09-25(Syfy Wire::Bad Astronomy) – Phil Plait:
In a little less than a month, NASA will launch an ambitious mission through the asteroid belt and out to Jupiter’s orbit. The spacecraft won’t be visiting Jupiter, though: It will fly by several asteroids that share an orbit with the giant planet, looking to investigate these fossils from the solar system’s early days.
This mission is pretty cool, but the flight it’ll take to get where it’s going is just nuts. …
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