Longtime Reader Stories
started reading Scientific American at a single-digit age. My first shocking article was Alan R. Sandage’s Redshift in 1956. Siam There have been ups and downs, but in my view the last few years have been better than ever. Bravo to all!
Christopher Clark Houston, Texas.
Solar Storm VS. Satellite
Rebecca Boyle’s The Threat of Satellite Constellations highlights the real and persistent threat that the proliferation of orbiting spacecraft poses to astronomy on Earth, and the lack of political will to address it. After all, what does the twinkle in the sky mean compared to the benefits of making the Internet available to everyone, everywhere on earth? The extreme danger of a Coronal Mass Ejection (CME) due to the strength of the Carrington event, which even at the time caused complete chaos and fires in telegraph stations. The impact of a large CME on modern technological civilization would be devastating.
What about the thousands of new satellites in low earth orbit (LEO)? The CME destroys electronics, constellations disintegrate, and inevitable collisions begin, each producing high-velocity debris. A chain reaction will occur, and LEO will become a practical barrier to human access to space. It will be up to the scientific community to generate the political will to address the spread control of LEO satellites. Because it’s in everyone’s interest, not just astronomers.
Daral cutting forestville, australia
Boyle’s reply: A geomagnetic storm similar to the record-keeping Carrington event, named after the British astronomer who observed solar flares that preceded the storm, was used to detect objects in orbit, outer space on the Moon, and on Earth. will have a devastating effect on objects of But solar activity doesn’t have to be so extreme to have an impact. As my story tells, geomagnetic activity in February 2022 caused 40 newly launched Starlink satellites to lose altitude and burn up in the Earth’s atmosphere. In fact, stronger storms can start a chain reaction in which malfunctioning satellites collide with each other.
Solar storms aren’t the only ones that can cause this disastrous phenomenon known as Kessler’s Syndrome. Besides reducing the number of LEO objects, the best preventative measure against CMEs may be a more accurate prediction of solar activity and ensuing geomagnetic storms. Better forecasts could provide enough warning for astronauts to evacuate and spacecraft operators to take protective measures. Solar-monitoring probes launched in the past five years could improve predictions of such storms.
peculiar life
The Life We Don’t Know, by Sarah Scholes, refers to the seemingly inevitable criterion that all life involves reproduction. But I don’t understand why reproduction is necessary. Indeed, it is possible that life forms are immortal, sentient, distinct from their environment, metabolizing without necessarily reproducing, and even moving about. There are at least two of her famous science fiction novels about the possibility of such existence. Solaris, by Stanislaw Lem (1961), and black clouds, By Fred Hoyle (1957).
Robert Caillot Prévessant-Mohan, France
Mr. Scholes reply: It is true that reproduction, or at least the inclusion of fertility, is standard in most definitions of life. But it ignores pesky complications. A typical complication is mule. An animal that everyone can agree to live, but usually an animal that cannot multiply itself further, with or without genetic mutations. And no flame is alive that can make more use of itself. Speaking of aging, there are actually functionally immortal creatures like Hydra on Earth. All of this means that the criteria for reproduction are not black and white, nor are the definitions of life the same. Humanity will likely continue to search for both extraterrestrial definitions and versions of life for a long time to come.
Antarctica skyscrapers
The Coming Collapse by Douglas Fox [November 2022]describes the imminent collapse of Thwaites Glacier, which contributes to sea level rise. There are questions about what will happen after the glacier disappears.
My recollection is that when the ice melts, the ice water movement does not change. Therefore, even if the already floating ice is stripped off the main glacier, it will not cause further sea level rise. is that correct? Additionally, apocalyptic stories about Thwaites seem to suggest that Thwaites falls into the sea with a large splash. Does it work that way, or does the glacier slip over days, weeks, months, or years?
Fred Branyate on mail
Fox’s reply: Ice shelves are already floating, so their melting does not directly contribute to sea level rise. But when the ice shelf disappears, the glacier behind it accelerates the flow to the ocean, which causes sea level to rise. After the collapse of the Larsen A, Larsen B, and Prince Gustav Ice Shelves on the Antarctic Peninsula, the glacial flow they supported accelerated by a factor of two to nine. Most of this speedup happened within a few months. Thwaites’ slide into the ocean won’t necessarily accelerate much when the ice shelf eventually disappears. But even the thinning and shrinking of ice shelves so far has accelerated glacier flow. The nearby Pine Island Glacier has likewise increased its current velocity by about 70%. The Thwaites and Pine Island glaciers are so massive compared to the smaller Antarctic Peninsula glaciers that even moderate glacier acceleration contributes much more to sea level rise.
Thwaites Glacier covers an area roughly the size of Florida, and not all of it slides into the ocean right away. Therefore, its “complete” collapse will take centuries. A major concern, however, is that if Thwaites loses the ice shelf and retreats past a point on the ground line, the glacier will become inherently unstable. We will be subjecting future humanity to the full extent of sea level rise, even if it takes centuries to figure it out.
errata
In “Concrete Cure” by Mark Fischetti, Nick Bockelman and Wil V. Srubar, it should be stated that the process of converting lime to clinker involves sintering (melting) lime, rather than both sintering and melting. was. It should also have been stated that the addition of mineralizers to lime lowers the sintering temperature rather than the melting temperature.
“Strike Back” by Alison Parshall [Advances, April 2023]I should have said that the laser consumes about 10 kilowatts per hour, not 10 kilowatts.
Imaginary Universe by Marc-Olivier Renoux, Antonio Asin and Miguel Navasquez [April 2023]the two equations in the top figure should be given by IFive = I and I8 = 1, not IFive = 1 and I8 = √–1. And a box that says “What is an imaginary number?” I should have said that rational numbers contain integers, not “rational numbers are integers”.
