Science

The odds of a sizable asteroid striking Earth are small, but they’re never zero. Large asteroids have struck Earth in the past, causing regional devastation. A really large asteroid strike likely contributed to the extinction of the dinosaurs. So we shouldn’t be too surprised that astronomers have discovered an asteroid with a better than 1% chance of striking our world. Those odds are large enough we should keep an eye on them, but not large enough that we should start packing bags and fleeing to the hills.

The rock, named 2024 YR4, is somewhere between 40 – 100 meters wide, which would make it a “city killer” asteroid. If it does strike Earth, it wouldn’t decimate human civilization and cause mass extinctions, but it could destroy a heavily populated area if it struck a city, or trigger a tsunami if it struck the ocean. It would back a punch similar to the 1908 Tunguska event in Northern Siberia.

So what is the overall risk of 2024 YR4? The scale most commonly used for asteroid impact risks is known as the Torino Scale. It combines the overall size and relative speed of an object with its odds of impact to assign a number ranging from 0 to 10, where 0 means there is no risk of impact and 10 means it’s time to call Bruce Willis to save us all from extinction. That said, the highest number any asteroid has had on the scale is 4. This was for the asteroid Apophis soon after its discovery, which has now been downgraded to 0.

Currently, 2024 YR4 has a 3 on the scale, which means it “merits attention by astronomers.” It is currently the only object with a number other than 0 on the Torino Scale, and it means a couple of things come into play. The first is that the International Asteroid Warning Network (IAWN) will work to pin down the orbit of the asteroid. Chaired by NASA, the IAWN coordinates with observatories around the world to make detailed observations of 2024 YR4. It will take time to gather enough data. But what will likely happen is that they will determine there is no risk of collision, and 2024 YR4 will be demoted to 0 on the scale.

The second thing initiated is the Space Mission Planning Advisory Group (SMPAG), chaired by the European Space Agency. They have a scheduled meeting next week when there will be some initial discussions about a possible mission to 2024 YR4 to shift its orbit. If we do find there is a real risk of impact, this group would ramp up quickly. But again, this isn’t likely.

Statistically, asteroids the size of 2024 YR4 strike Earth every couple thousand years or so. This is why astronomers track these objects and are constantly looking for more. So even though the odds of an impact are never zero, with planning and preparation we should be able to ensure that any real risk can be mitigated.

The post An Asteroid Has a 1% Chance of Impacting Earth in 2032 appeared first on Universe Today.

A team of scientists has made the first experimental measurements of laser-induced motions of miniature lightsails in the lab.

A team of scientists has made the first experimental measurements of laser-induced motions of miniature lightsails in the lab.

A study assessed the impact of electric fans on the body core temperature and heart rate of 18 participants aged 65-85 years, who were exposed to a simulated extreme indoor environment of 36 degrees Celsius with 45 percent relative humidity for eight hours. The results showed participants were unaffected by fan use, with all three of the experimental conditions resulting in an average body core temperature of 38.3 C and heart rate of 100 beats per minute.

It's been known for some time that radiation impacts the structural integrity of concrete. However, until now the details of this were unknown. Researchers can finally demonstrate what properties of concrete affect its structural characteristics under different neutron radiation loads. Their findings raise some concerns whilst reducing others; for example, quartz crystals in concrete can heal themselves, potentially allowing some reactors to run for longer than initially thought possible.

Researchers measured very precisely atomic masses of radioactive lanthanum isotopes and found an interesting feature in their nuclear binding energies. The discovery provides essential data for understanding how elements heavier than iron are produced in the Cosmos and triggers new research to elucidate the underlying nuclear structure causing this unexpected change in nuclear binding energies.

Researchers measured very precisely atomic masses of radioactive lanthanum isotopes and found an interesting feature in their nuclear binding energies. The discovery provides essential data for understanding how elements heavier than iron are produced in the Cosmos and triggers new research to elucidate the underlying nuclear structure causing this unexpected change in nuclear binding energies.

Researchers are breaking limits by increasing the temperature multiferroics can operate at, from room temperature up to a blistering 160 degrees Celsius.

To finish up my reportage on the USC conference on Censorship in STEM, I present a video Day 3 for your delectation.  It’s 6½ hours long, but below I’ll give the time marks for three items of interest, one of which is of interest only because it includes ME.

First the whole day; I’ve put the written schedule at the bottom so you can find the other talks.

The first talk is by heterodox black political scientist Wilfred Reilly, speaking about ten taboo topics; it begins at the beginning. I won’t list the taboos, so you’ll have to listen to the talk to see them.

The second talk, involving Julia Schaletzky, Luana Maroja, and me, begins at 4:29:51; its topic is “Censorship, sciences, and the life sciences”.  I can’t bear to listen to myself again. But I advanced the video 5:26:00, where some guy asks me about filling the “god-shaped hole” in humanity, and by eliminating religion the hole is filled by solipsism, some undefined “meta-narrative”. I got as heated as I ever do in a meeting, which is not very heated, but did stand my ground.

But below a talk you must hear. It’s from Greg Lukianoff, President of the Foundation for Individual Rights and Expression (FIRE). I think it was the best talk of the conference, and was also the last one. Fortunately, you can avoid scrolling around above because the talk is also posted as a standalone video (below). It’s a bit over 52 minutes long, and the topic is “How cancel culture destroys trust in expertise.”  Lukianoff is a passionate and eloquent speaker.

It’s a very good talk packed with information and slides, beginning with what happened to professors during the Red Scare in America the 40s and 50s, and then going on to the increase in cancellation happening today: how many professors get fired, how many deplatforming attempts are happening and how fast they’re increasing, and how schools rate on free speech. (Lukianoff really doesn’t like Harvard or Columbia; see 28:00, at 44:30, and at 51:44, when he says that Columbia should declare itself a “technical school.”)

Lukianoff also gives a number of examples of demonization or cancellation, all of which bear on how speech is chilled (note his comment on the Nature Human Behavior policy), and describes some ongoing FIRE lawsuits to promote free speech.

There are a full twenty minutes of good questions, the first by Jonathan Rauch (“What about the ACLU, the AAUP, and other organizations like yours?”). All of the questions get thorough and thoughtful answers.

 

Finally, here’s the schedule for day 3:

From contact with aliens courtesy of Adrian Tchaikovsky to the childhood writings of Octavia E. Butler, February’s sci-fi offerings are rich and strange

Male dolphins have been observed shooting jets of urine into the air and other dolphins seem to follow the stream, perhaps to pick up social cues

Defenders of Dr. Vinay Prasad fake a concern about tone to intimidate critics and create a safe space for his misinformation.

The post Defenders of Dr. Vinay Prasad’s Vulgar, Vengeful Vitriol Have No Right to Sanctimoniously Scold Anyone About Decorum first appeared on Science-Based Medicine.

A muscle that we thought served no purpose beyond enabling some people to wiggle their ears is actually active when we are trying hard to listen

Mars haunts us as a vision of a planet gone wrong. It was once warm and wet, with rivers flowing across its surface and (potentially) simple life residing in its water bodies. Now it’s dry and freezing.

Could Earth suffer this fate? Are there innumerable other worlds throughout the Universe that were habitable for a period of time before becoming uninhabitable?

To answer those questions, we have to answer one of the big questions in space science: What drove the changes on Mars? New research shows that hydrogen played a critical role in keeping ancient Mars warm for periods of time, as the planet’s temperature oscillated between warm and cold.

The research is “Episodic warm climates on early Mars primed by crustal hydration.” It’s published in Nature Geoscience, and the lead author is Danica Adams, a postdoctoral fellow in the Department of Earth and Planetary Sciences at Harvard University.

“Early Mars is a lost world, but it can be reconstructed in great detail if we ask the right questions.”

Robin Wordsworth, Harvard University.

There’s ample evidence of flowing surface water on ancient Mars. NASA’s Perseverance rover is exploring Jezero Crater, an ancient paleolake with deep sediment deposits carried there by flowing water. Satellite views show numerous ancient river channels. There’s also clear evidence of ancient lakes.

For a long time, the dominant scientific thought was that Mars was once warm and then became cold. In recent years, more thorough evidence suggests that Mars oscillated between being a warm and a cold planet.

If that’s true, what drove those oscillations?

The first difficulty in explaining early warm periods on Mars is the faint young Sun paradox. Astrophysicists calculate that the young Sun emitted only 70% of the energy it does now. How could Mars have had liquid surface water with so little solar output?

“It’s been such a puzzle that there was liquid water on Mars, because Mars is further from the sun, and also, the sun was fainter early on,” said lead author Danica Adams in a press release.

Evidence suggests that Mars once had enough water for an equivalent global ocean from 100 m to 1,500 m deep during the planet’s late Noachian period. Scientists have found hundreds of lakebeds from the Noachian, some as large as the Caspian Sea. However, the planet is suspected to have been too cold to host this much liquid water without a more efficient heat-trapping atmosphere. CO2 alone couldn’t do it, but researchers think that a more hydrogen-rich atmosphere could.

Lake Eridania, also known as the Eridania Sea, is a massive ancient lakebed on ancient Mars. It covered approximately 1.1 million sq. km. and was as deep as 1000 meters in some parts. Image Credit: By Jim Secosky chose this image NASA – https://photojournal.jpl.nasa.gov/figures/PIA22059_fig1.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=63303137

The problem is that hydrogen doesn’t tend to persist in atmospheres.

“Greenhouse gases such as H2 in a CO2-rich atmosphere could have contributed to warming through collision-induced absorption, but whether sufficient H2 was available to sustain warming remains unclear,” the authors write in their paper. Collision-induced absorption (CIA) is when molecules in a gas collide, and interactions from the collision allow molecules to absorb light. CIA could amplify the atmospheric CO2’s warming effect.

If there was a hydrogen source that allowed the atmosphere to replenish itself, that could explain how Mars oscillated between cold and dry and warm and wet. The researchers used a combined photochemical and climate model to understand how the atmosphere responded to climate variations and reactions between H2O and rock.

“Early Mars is a lost world, but it can be reconstructed in great detail if we ask the right questions,” said study co-author Robin Wordsworth from Harvard. “This study synthesizes atmospheric chemistry and climate for the first time to make some striking new predictions – which are testable once we bring Mars rocks back to Earth.”

The team’s research showed that early Mars had two distinct climate states that persisted for long timescales. The warm climate sustained surface liquid water and lasted between 100,000 and 10 million years. These periods were created and sustained by H2 from crustal hydration with some help from volcanic activity. During crustal hydration, water is lost to the ground, and H2 is released into the atmosphere. The cool climate lasted about 10 million years and featured a CO-dominated atmosphere caused by oxidant sinks in the planet’s surface.

This figure from the paper shows Mars’ H, C, and O chemistry, including ground sinks and escape processes. On the left are the cool and dry epochs triggered by oxygen lost to the crust. On the right are the warm and wet epochs driven by crustal hydration and oxidation that release H2. “In all epochs, CO2 and H2O photolysis (energy from photons represented in the cartoon as hv) drives the photochemistry, and escape of H, C and O is considered,” the authors write. In modern Mars, however, dissociative recombination is how oxygen primarily escapes. Image Credit: Adams et al. 2025.

“We find that H2 <molecular hydrogen> outgassing from crustal hydration and oxidation, supplemented by transient volcanic activity, could have generated sufficient H2 fixes to transiently foster warm, humid climates,” the authors explain.

The team’s models showed that Mars’ climate oscillated like this for about 40 million years during the Noachian and Hesperian periods. Each warm period lasted at least 100,000 years. According to the researchers, these timescales are in agreement with the length of time it took to carve Mars’ river valleys.

The planet’s atmospheric chemistry fluctuated during these periods. As sunlight struck CO2, it was converted to CO. During warm periods, the CO cycled back into CO2, and CO2 and H2 were dominant.

During cold periods, the CO recycling slowed down, CO built up in the atmosphere, and it triggered a more oxygen-reduced state. In this way, the redox state of the atmosphere oscillated dramatically over time.

“We’ve identified time scales for all of these alternations,” Adams said. “And we’ve described all the pieces in the same photochemical model.”

Mars’s modern-day surface supports the researchers’ alternating atmospheric redox hypothesis. The surface shows a “paucity of carbonates,” the researchers explain in their paper. These should form in an atmosphere dominated by CO2 where neutral pH water is present, as long as there is abundant open-system crustal alteration at the planet’s surface. Adams and her co-researchers say their hypothesis can explain the lack of carbonates.

Carbonates were first detected on Mars in 2008, and scientists expected to find large deposits of them. However, those large deposits were never found. If early Mars had abundant water for a long time, there would be abundant carbonates.

Though carbonates are present on Mars, they’re not abundant. If Mars had been wet for a long time, they should be abundant. Image Credit: ESA.

Mars’ surface rocks also contain both oxidized and reduced species of minerals. The authors say that is evidence the surface is far out of equilibrium, which their hypothesis supports. “While both oxidized and reduced species may form under one climate, the deposition rate of different species is sensitive to the climate. For example, warm climates preferentially deposit nitrate while cool climates preferentially deposit nitrite,” the authors write.

In any case, Mars is an extremely interesting puzzle. Without plate tectonics, its surface is largely unchanged from ancient times. Unlike Earth, which recycles its surface and erases evidence, evidence of Mars’ warm, wet periods is easy to see. “It makes a really great case study for how planets can evolve over time,” lead author Adams said.

Much of what scientists hypothesize about Mars can only be confirmed by in-situ measurements. The NASA rovers MSL Curiosity and Perseverance both have onboard labs to study rocks. Perseverance, however, is also caching rock samples for eventual return to Earth. Those samples, if they make it to Earth labs, will be critical in answering our questions about Mars.

“Hence, full interpretation of the redox paradox will require careful comparison of our alternating atmospheric redox hypothesis with chemical and isotopic datasets collected in situ and with igneous and water-altered rocks from the first 1–2 billion years of Mars’s history that comprise the samples presently being collected by the Perseverance rover,” the authors conclude.

This hypothesis raises questions about Mars’s habitability in the past. According to our understanding, oscillations between warm and wet and cold and dry pose a significant barrier to life starting and evolving. But that’s beyond the scope of this paper.

The post How Hydrogen Kept Early Mars Warm appeared first on Universe Today.

The development of vehicle components is a lengthy and therefore very costly process. Researchers have developed a method that can shorten the development phase of the powertrain of battery electric vehicles by several months. A team is combining simulation models of components with evolutionary optimization algorithms. This AI system automatically optimizes the entire powertrain -- from the power electronics to the electric machine through to the transmission -- in line with the manufacturer's technical requirements, taking into account targets such as production costs, efficiency and package space requirements in the vehicle.

The development of vehicle components is a lengthy and therefore very costly process. Researchers have developed a method that can shorten the development phase of the powertrain of battery electric vehicles by several months. A team is combining simulation models of components with evolutionary optimization algorithms. This AI system automatically optimizes the entire powertrain -- from the power electronics to the electric machine through to the transmission -- in line with the manufacturer's technical requirements, taking into account targets such as production costs, efficiency and package space requirements in the vehicle.

Skyrmions are nanometer- to micrometer-sized magnetic whirls that exhibit particle-like properties and can be moved efficiently by electrical currents. These properties make skyrmions an excellent system for new types of data storage or computers. However, for the optimization of such devices, it is usually too computationally expensive to simulate the complicated internal structure of the skyrmions. One possible approach is the efficient simulation of these magnetic spin structures as particles, similar to the simulation of molecules in biophysics. Until now, however, there has been no conversion between simulation time and experimental real time.

Skyrmions are nanometer- to micrometer-sized magnetic whirls that exhibit particle-like properties and can be moved efficiently by electrical currents. These properties make skyrmions an excellent system for new types of data storage or computers. However, for the optimization of such devices, it is usually too computationally expensive to simulate the complicated internal structure of the skyrmions. One possible approach is the efficient simulation of these magnetic spin structures as particles, similar to the simulation of molecules in biophysics. Until now, however, there has been no conversion between simulation time and experimental real time.

Researchers have demonstrated a new, unsupervised machine learning approach to find new patterns in the auxiliary channel data of the Laser Interferometer Gravitational-Wave Observatory.

Researchers have demonstrated a new, unsupervised machine learning approach to find new patterns in the auxiliary channel data of the Laser Interferometer Gravitational-Wave Observatory.