Astro Blog

https://www.science.org/content/article/evidence-giant-asteroid-strike-may-be-buried-under-wyoming By Paul Voosen, Science Magazine.  Excerpt: Some 280 million years ago, before the rise of the Rocky Mountains—or even the dinosaurs—a 2.5-kilometer-wide asteroid smashed into the supercontinent of Pangaea, near the eastern border of present-day Wyoming. The impact’s heat and shock wave would have killed anything within 400 kilometers, making it one of the largest asteroid strikes in North American history. ...And there the crater may sit, kilometers down, even to this day. That’s the scenario painted in new work. Researchers haven’t found the crater itself, but they have identified a series of 31 smaller craters, each no wider than a U.S. football field. These “secondary” craters would have been formed by boulders ejected by the impact, landing up to 200 kilometers away. It is the first time a secondary crater field—commonly seen on other planetary bodies, including the Moon—has bee...

https://www.nytimes.com/2022/02/15/science/mars-nasa-perseverance.html By   Kenneth Chang , The New York Times.  Excerpt: ...NASA’s Perseverance rover ...On Feb. 18 last year, the spacecraft carrying the rover pierced the Martian atmosphere at 13,000 miles per hour. ...Twelve months later, Perseverance is nestled within  a 28-mile-wide crater known as Jezero . From the topography, it is evident that more than three billion years ago, Jezero was a body of water roughly the size of Lake Tahoe, with rivers flowing in from the west and out to the east. One of the first things Perseverance did was deploy Ingenuity, a small robotic helicopter and the first such flying machine to take off on another planet. Perseverance also demonstrated a technology for generating oxygen that will be crucial whenever astronauts finally make it to Mars. The rover then set off on a diversion from the original exploration plans, to study the floor of the crater it landed in. ...collect cores of ro...

https://eos.org/articles/to-make-a-big-moon-start-with-a-small-planet By Kimberly M. S. Cartier , Eos/AGU.  Excerpt: In a contest of which planet in the solar system has the most relatively massive moon, Earth takes the prize. The Moon is roughly 1% of Earth’s mass, whereas the moons of all the remaining moon-bearing planets—that’s all of them save for Mercury and Venus—are less than one ten thousandth their planets’ masses. ...“We think that a giant impact is a very efficient way to form fractionally large moons,” said  Miki Nakajima , a planetary scientist at the University of Rochester in New York. Large collisions are thought to be a common occurrence in the chaos of a still-forming solar system, but if all giant impacts formed fractionally large moons, our solar system would be rife with them. ...Using computer simulations, Nakajima and her colleagues explored what happens when rocky or icy would-be planets of various sizes collide. The researchers found that after such a...

https://www.nytimes.com/2022/02/09/science/spacex-satellites-storm.html By  Robin George Andrews , The New York Times.  Excerpt: Over the past three years, SpaceX has deployed thousands of satellites into low-Earth orbit as part of its business to beam high-speed internet service from space. But the company’s latest deployment of 49 new satellites after a Feb. 3 launch did not go as planned. As a consequence of a geomagnetic storm triggered by a recent outburst of the sun, up to 40 of 49 newly launched Starlink satellites have been knocked out of commission. They are in the process of re-entering Earth’s atmosphere, where they will be incinerated. ...The sun has an 11-year-long cycle in which it oscillates between hyperactive and quiescent states. Presently, it is ramping up to its peak, which has been forecast to  arrive around 2025 . This recent solar paroxysm was relatively moderate by the sun’s standards. “I have every confidence that we’re going to see an extreme ev...

https://eos.org/articles/a-giant-impact-triggered-earthquakes-for-thousands-of-years By  Katherine Kornei , Eos/AGU.  Excerpt: When an asteroid struck South Africa during the Precambrian, earthquakes rocked the region for millennia as Earth’s crust reequilibrated, new research reveals.…