WOW! It Wasn’t Aliens After All!

August 20, 2024 by 21 Comments

There may not be many radio astronomy printouts that have achieved universal fame, but the one from Ohio State University’s Big Ear telescope upon which astronomer [Jerry R. Ehman] wrote “WOW!” is definitely one of them. It showed an intense one-off burst that defied attempts to find others like it, prompting those who want to believe to speculate that it might have been the product of an extraterrestrial civilization. Sadly for them the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo has provided an explanation by examining historical data from the Arecibo telescope.

The radio signal in question lay on the hydrogen line frequency at 1420 MHz, and by looking at weaker emissions from cold hydrogen clouds they suggest that the WOW! signal may have come from a very unusual stimulation of one of these clouds. A magnetar is a type of neutron star which can create an intense magnetic field, and their suggestion is that Big Ear was in the lucky position of being in the right place at the right time to see one of these through a hydrogen cloud. The field would excite the hydrogen atoms to maser-like emission of radiation, leading to the unexpected blip on that printout.

There’s a question as to whether speculation about aliens is helpful to the cause of science, but in answer to that we’d like to remind readers that we wouldn’t be talking about magnetars now without it, and that the WOW! signal was in fact part of an early SETI experiment. Better keep on searching then!

Meanwhile readers with long memories will recollect us looking at the WOW! signal before.

Learning How A Nuclear Missile Stays On Target

August 20, 2024 by 75 Comments

In 1962, unlike today, most things didn’t have computers in them. After all, the typical computer of the day was a fragile room-sized box that required a gaggle of high priests to service it. But the Minuteman I nuclear missile was stuffed full of pre-GPS navigation equipment and a computer. In a few years, by 1970, the Minuteman III could deliver a warhead 13,000 km with an accuracy of 200 meters. Each one cost about a half million dollars, but that’s almost five million in today’s money. [Ken] takes on a very detailed tour of the computers and avionics that were nothing short of a miracle — and a highly classified miracle — in the 1960s.

The inertial navigation relied on a gyroscope, which in those days, were large and expensive. The Minuteman I required alignment with a precise angle relative to the North Star which naturally wasn’t visible from inside the silo. By the time Minuteman II arrived, they’d figured out an easier way to orient the missiles.

Continue reading “Learning How A Nuclear Missile Stays On Target” →

Radio Apocalypse: HFGCS, The Backup Plan For Doomsday

August 5, 2024 by 15 Comments

To the extent that you have an opinion on something like high-frequency (HF) radio, you probably associate it with amateur radio operators, hunched over their gear late at night as they try to make contact with a random stranger across the globe to talk about the fact that they’re both doing the same thing at the same time. In a world where you can reach out to almost anyone else in an instant using flashy apps on the Internet, HF radio’s reputation as somewhat old and fuddy is well-earned.

Like the general population, modern militaries have largely switched to digital networks and satellite links, using them to coordinate and command their strategic forces on a global level. But while military nets are designed to be resilient to attack, there’s only so much damage they can absorb before becoming degraded to the point of uselessness. A backup plan makes good military sense, and the properties of radio waves between 3 MHz and 30 MHz, especially the ability to bounce off the ionosphere, make HF radio a perfect fit.

The United States Strategic Forces Command, essentially the people who “push the button” that starts a Very Bad Day™, built their backup plan around the unique properties of HF radio. Its current incarnation is called the High-Frequency Global Communications System, or HFGCS. As the hams like to say, “When all else fails, there’s radio,” and HFGCS takes advantage of that to make sure the end of the world can be conducted in an orderly fashion.

Continue reading “Radio Apocalypse: HFGCS, The Backup Plan For Doomsday” →

Spin Your Own Passive Cooling Fibres

July 31, 2024 by 4 Comments

When the temperature climbs, it’s an eternal problem: how to stay cool. An exciting field of materials science lies in radiative cooling materials, things which reflect so much incoming heat that they can cool down from their own radiation rather than heating up in the sun. It’s something [NightHawkInLight] has been working on over a series, and he’s dropped a very long video we’ve placed below. It’s ostensibly about spinning radiative cooling fibers, but in fact provides a huge quantity of background as well as a bonus explanation of cotton candy machines.

These materials achieve their reflectivity by creating a surface full of microscopic bubbles. It’s the same process that makes snow so white and reflective, and in this case it’s achieved by dissolving a polymer in a mixture of two solvents. The lower boiling point solvent evaporates first leaving the polymer full of microscopic bubbles of the higher boiling point solvent, and once these evaporate they leave behind the tiny voids. In the video he’s using PLA, and we see him experimenting with different solvents and lubricants to achieve the desired result. The cotton candy machine comes in trying to create fibers by melting solid samples, something which doesn’t work as well as it could so instead he draws them by hand with a small rake.

When he tests his mat of fibers in bright sunlight the effect is almost magical if we didn’t already know the mechanism, they cool down by a few degrees compared to ambient temperature and the surrounding control materials. This is a fascinating material, and we hope we’ll see more experimenters working with it. You won’t be surprised to hear we’ve featured his work before.

Continue reading “Spin Your Own Passive Cooling Fibres” →

Small Mammals Appear To Have A Secret Infrared Sense

July 22, 2024 by 23 Comments

If you’ve ever watched Predator, you’ve noted the tactical advantage granted to the alien warrior by its heat vision. Indeed, even with otherwise solid camoflauge, Dutch and his squad ended up very much the hunted.

And yet, back in reality, it seems the prey might be the one with the ability to sense in the infrared spectrum. Research has now revealed this unique ability may all be down to the hairs on the back of some of the smallest mammals.

Continue reading “Small Mammals Appear To Have A Secret Infrared Sense” →

Reviewing Nuclear Accidents: Separating Fact From Fiction

July 22, 2024 by 93 Comments

Few types of accidents speak as much to the imagination as those involving nuclear fission. From the unimaginable horrors of the nuclear bombs on Nagasaki and Hiroshima, to the fever-pitch reporting about the accidents at Three Mile Island, Chernobyl and Fukushima, all of these have resulted in many descriptions and visualizations which are merely imaginative flights of fancy, with no connection to physical reality. Due to radiation being invisible with the naked eye and the interpretation of radiation measurements in popular media generally restricted to the harrowing noise from a Geiger counter, the reality of nuclear power accidents in said media has become diluted and often replaced with half-truths and outright lies that feed strongly into fear, uncertainty, and doubt.

Why is it that people are drawn more to nuclear accidents than a disaster like that at Bhopal? What is it that makes the one nuclear bomb on Hiroshima so much more interesting than the firebombing of Tokyo or the flattening of Dresden? Why do we fear nuclear power more than dam failures and the heavy toll of air pollution? If we honestly look at nuclear accidents, it’s clear that invariably the panic afterwards did more damage than the event itself. One might postulate that this is partially due to the sensationalist vibe created around these events, and largely due to a poorly informed public when it comes to topics like nuclear fission and radiation. A situation which is worsened by harmful government policies pertaining to things like disaster response, often inspired by scientifically discredited theories like the Linear No-Threshold (LNT) model which killed so many in the USSR and Japan.

In light of a likely restart of Unit 1 of the Three Mile Island nuclear plant in the near future, it might behoove us to wonder what we might learn from the world’s worst commercial nuclear power disasters. All from the difficult perspective of a world where ideology and hidden agendas do not play a role, as we ask ourselves whether we really should fear the atom.

Continue reading “Reviewing Nuclear Accidents: Separating Fact From Fiction” →

The Continuing Venusian Mystery Of Phosphine And Ammonia

July 19, 2024 by 18 Comments

The planet Venus is in so many ways an enigma. It’s a sister planet to Earth and also within relatively easy reach of our instruments and probes, yet we nevertheless know precious little about what is going on its surface or even inside its dense atmosphere. Much of this is of course due to planets like Mars getting all the orbiting probes and rovers scurrying around on its barren, radiation-blasted surface, but we had atmospheric probes descend through Venus’ atmosphere, so far to little avail. Back in 2020 speculation arose of phosphine being detected in Venus’ atmosphere, which caused both excitement and a lot of skepticism. Regardless, at the recent National Astronomy Meeting (NAM 2024) the current state of Venusian knowledge was discussed, which even got The Guardian to report on it.

In addition to phosphine, there’s speculation of ammonia also being detectable from Earth, both of which might be indicative of organic processes and thus potentially life. Related research has indicated that common amino acids essential to life on Earth would be stable even in sulfuric droplets like in Venus’ atmosphere. After criticism to the original 2020 phosphine article, [Jane S. Greaves] et al. repeated their observations based on feedback, although it’s clear that the observation of phosphine gas on Venus is not a simple binary question.

The same is true of ammonia, which if present in Venusian clouds would be a massive discovery, which according to research by [William Bains] and colleagues in PNAS could explain many curious observations in Venus’ atmosphere. With so much uncertainty with remote observations, it’s clear that the only way that we are going to answer these questions is with future Venus missions, which sadly remain rather sparse.

If there’s indeed life on Venus, it’ll have a while longer to evolve before we can go and check it out.