Science

In a few billion years, our Sun will die. It will first enter a red giant stage, swelling in size to perhaps the orbit of Earth. Its outer layers will be cast off into space, while its core settles to become a white dwarf. Life on Earth will boil away, and our planet itself might be consumed by the Sun. White dwarfs are the fate of all midsize stars, and given the path of their demise, it seems reasonable to assume that any planets die with their sun. But the fate of white dwarf planets may not be lifeless after all.

More than a dozen planets have been discovered orbiting white dwarf stars. That’s a small fraction of the known exoplanets, but it tells us that planets can survive the red giant stage of a Sun-like star. Some planets may be consumed, and the orbits of survivors might be dramatically affected, but some planets retain a stable orbit. Any planets that were in the habitable zone of the star would die off, but a new study suggests that some white dwarf planets might give life the foothold it needs to evolve again.

Although white dwarfs don’t undergo nuclear fusion, they do remain warm for billions of years. Young white dwarfs can have a surface temperature of 27,000 K or more, and it takes billions of years for them to cool. Since the simple definition of a star’s habitable zone is simply the range where a planet is warm enough for liquid water, this means all white dwarfs have a habitable zone. Unlike main sequence stars, however, this region would migrate inward as the star cools. But in this new work, the authors show that white dwarfs have a habitable zone that would be warm enough for life across billions of years. For a white dwarf of about 60% of the Sun’s mass, part of the habitable zone would persist for nearly 7 billion years, which is more than enough time for life to evolve and thrive on a world. In comparison, the Earth is less than 5 billion years old.

Habitable zone of a white dwarf over time. Credit: Whyte, et al

Of course, for life to appear on a white dwarf planet, simply being warm isn’t enough. To have the kind of complex life we see on Earth, the spectrum of starlight would need to provide the right kind of energy for things like photosynthesis without ionizing the planet’s atmosphere. The spectra of white dwarfs are shifted much more to the ultraviolet than the visible and infrared, but the authors show that ionizing radiation would not be severe, and the amount of UV would allow for Earth-like photosynthesis. The optimal habitable zone would be close to the white dwarf, similar to the habitable zone of the TRAPPIST-1 red dwarf.

Just because a white dwarf planet might be home to life, that doesn’t mean they are. We know life can exist around a Sun-like star, but we’d need clear evidence to say the same is true for white dwarfs. That’s where the second part of this work comes in. Since white dwarfs are bright for their size and habitable planets would need to orbit them closely, our ability to gather evidence on them is good. The James Webb Space Telescope (JWST), for example, is sensitive enough to observe the atmospheric spectra of white dwarf planets as they transit. A few hours of observational time could be enough to get a spectrum sharp enough to detect biosignatures.

All that said, finding life on a white dwarf planet is a long shot. The planets would likely have to migrate inward during the latter part of the red dwarf stage, maintain a stable orbit, and somehow retain or recapture the kind of water-rich atmosphere you need for terrestrial life. That’s a big ask. But given how easy it might be to detect biosignatures, it’s worth taking a look.

Reference: Whyte, Caldon T., et al. “Potential for life to exist and be detected on Earth-like planets orbiting white dwarfs.” arXiv preprint arXiv:2411.18934 (2024)

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From perfecting your hydration levels to tracking hormones, analysing your perspiration can give new insights into your fitness and how to improve it

Now is the time to catch Jupiter at its best.

The King of the Planets rules the winter night skies. Early December gives sky watchers a good reason to brave the cold, as Jupiter shines at its best. Look for the regal planet rising in the east at sunset, while the Sun sets to the west.

Why Opposition?

For an outer planet, we call this point ‘opposition’ as the planet sits ‘opposite’ to the Sun from our Earthly perspective. This also means that Jupiter is above the horizon for the entire evening: low to the east at sunset, high to the south at local midnight, and setting to the west at sunset.

Opposition for Jupiter in 2024 occurs on Saturday, December 7th. Jupiter is closest to the Earth (611 million kilometers distant) a day prior on December 6th. The discontinuity exists because Jupiter is currently moving away from us, while we’re headed towards the Sun.

A double shadow moon transit from August 14th, 2024. Credit: Thad Szabo.

Jupiter reached perihelion early last year on January 20-21st, 2023, while Earth heads towards perihelion about a month from now on January 4, 2025. On an 11.9 year orbit, we won’t have another perihelion-opposition year for Jupiter until 2034.

Jupiter at opposition on December 7th. credit: Stellarium.

To the naked eye, Jupiter shines as a -2.8 magnitude ‘star’, in the constellation Taurus the Bull. This position, along with an opposition just two weeks prior to the December southward solstice on the 21st assures that Jupiter dominates the scene for northern hemisphere observers in 2024, riding high in the nighttime sky.

A ground-based view of Jupiter and its moon Io, versus the view as seen by NASA’s Juno spacecraft. Credit: NASA/Juno/Efrain Morales. Seeing Double

Zooming in on Jupiter with a telescope even at low power gives you a view similar to Galileo’s just over four centuries ago. The four major moons of Io, Europa, Ganymede and Callisto easily pop out, even in a low power binocular view. At opposition, the moons and even Jupiter itself cast shadows nearly straight back, slowly changing angle towards quadrature. While triple shadow moon transits are rare (the next one isn’t until March 20th, 2032) double shadow transits happen in seasonal cycles a few times a year. The next one involving Io and Ganymede starts on December 23rd.

A simulation of the double shadow transit coming up on December 23rd. Credit: Starry Night.

Jupiter’s fast 10 hour rotation also means that you can witness one full rotation of the gas giant in one night. This means you can spot the Great Red Spot on any given evening if you wait long enough, though to my eye, it looks more like the ‘Pale Salmon Spot’ in recent years. The major northern and southern equatorial belts are also easily apparent at low power, though the Southern Equatorial Belt has been known to pull a vanishing act roughly once a decade or so… it last did so on 2010-2011, so you could say we’re due.

JWST provides a unique infrared view of Jupiter, showing the atmospheric depth of the belts and the Great Red Spot. NASA/JWST.

Jupiter is so bright that it can cast a slight shadow, something that’s worth watching for on the freshly fallen snow. The Moon also reaches Full for December on the 15th, and passes five degrees north of the planet on the 14th, offering a chance to see Jupiter in the daytime, just before sunset.

A daytime Jupiter near the Moon. Credit: Dave Dickinson. A Teaser for Jupiter in 2025

There’s also more Jovian action in store. In the coming years, Callisto (the only major moon that can ‘miss’ Jove) resumes transits in 2026. This leads the way into the next bi-decadal mutual-eclipse season for the moons.

Don’t miss Jupiter at opposition for 2024… it’s worth braving the cold for.

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Yes, this analysis and report are from Texas’s Republican Senator Ted Cruz, but let’s not use that to dismiss his press release and report from the U.S. Senate Committee on Commerce, Science & Transportation. If you won’t read something simply because it’s from Ted Cruz’s office, you are at the wrong site.

At any rate, the press release”reveals how Biden-Harris diverted billions from science to DEI activists.”  I have no reason to doubt this claim given the increasing tendency of federal funding agencies (the NSF in this case) to divert money from real science into ideological project furthering the “progressive” agenda. But if you want to undercut this claim, simply look at the projects that are classified as “DEI activism”. Only a few are offered, and they support the claim, which is not surprising.

Although I finished my last grant about eight years ago, I am told by active researchers, scientists I know personally, that the entire system has changed in the last decade, exactly in the way this report describes. And the pressure to change from pure science to Social Justice must have come from the top. I don’t know who applied it, but the buck stops at the President’s desk, and it was clearly the Biden Administration that approved the change in direction.

Click the headline below to read, and you can find the committee’s 43-page report here.

The upshot is that over the four years that Biden was President, over two billion dollars were allocated to projects that Cruz’s committee classified as “DEI grants”. Over 3,400 such grants were given.  Disturbingly, such grants used up only 0.29% of the funding in 2021, but their number swelled each year until, in 2024, they used up over 27% of NSF funding.

The three paragraphs below are taken from the press release. Yes, the language is from the Right (i.e., “neo-Marxist” and “radical perspectives”), but who can deny that the DEI agenda has damaged universities, making them more divisive and imposing an orthodoxy on thought and research that’s inimical to free thinking and academic freedom?

In its first week, the Biden-Harris administration mandated that all taxpayer-funded scientific research and development (R&D) must incorporate Diversity, Equity, and Inclusion (DEI) values. Sen. Cruz’s investigation found that in response to this directive, NSF allocated over $2.05 billion to thousands of research projects that promoted neo-Marxist perspectives or DEI tenets. Taxpayer dollars supported projects of questionable scientific merit, often led by researchers who used federal R&D dollars to drive divisive, extremist ideologies in their classrooms and on their campuses.

The Committee’s analysis identified 3,483 grants—over 10% of all NSF grants awarded during the Biden-Harris administration—totaling more than $2.05 billion went to questionable projects that promoted DEI or pushed neo-Marxist perspectives about enduring class struggle. The Committee grouped these grants into five categories: Status, Social Justice, Gender, Race, and Environmental Justice.

The report reveals, through examples across categories, that many of the most extreme research proposals were led by principal investigators who are also promoting radical perspectives through on-campus activism and in their classrooms.

Here are two figures from the report itself (click pictures to enlarge) showing the number of grants and total funding in each of five “DEI” categories:

And the NSF obeyed the Biden administration’s directive. This shows the total NSF funding per year, and the amount and proportion of funding directed towards what are classified as DEI initiatives:

The report also gives examples of grants that sound ludicrous. These of course are cherry-picked and remind me of Senator William Proxmire’s old “Golden Fleece Awards,” (Proxmire was a Democrat), given to agencies who squandered public money. Below are two examples cited, and I urge those who want to examine the Cruz Committee’s contentions to examine them further. Others are given in the report. Bolding is from the press release:

• Shirin Vossoughi is an associate professor of learning sciences at Northwestern University and the co-principal investigator for a $1,034,751 NSF grant awarded in 2023 for a project titled, “Reimagining Educator Learning Pathways Through Storywork for Racial Equity in STEM.” Vossoughi credits Marxist traditions for her decision to teach children “the meaning of ‘genocide’ and ‘apartheid’” after Hamas’s attack against Israel.

 

• In 2023, NSF awarded Georgia Institute of Technology’s (Georgia Tech) Kelly Cross $99,791 to “disrupt[] racialized privilege in the STEM classroom” by acknowledging “Whiteness and White Supremacy” are “deeply ingrained in the past, present and future of U.S. Higher education.” Cross sought to “subvert[] these toxic systems… to creat[e] a more equitable educational system” and “initiate a national conversation about addressing racial inequity and White Supremacy in the STEM profession and classroom” with the support of the grant.

There are further examples given in the report, but you can look at them yourself. Here are the conclusions taken from the paper, not the press release:

The Biden-Harris administration has methodically weaponized federal agencies to drive a partisan, divisive agenda. President Biden and Vice President Harris tasked federal science agencies to restructure scientific investigation into an exercise in categorizing individuals by their background, not by their talent and capabilities.

This year, almost 30 percent of NSF grant projects will seek to promote these divisions. Already, billions of taxpayer dollars have been wasted. These grants both crowd out other kinds of research that could advance understanding of the physical world and advance a deeply divisive philosophy antithetical to the tenets of empirical scientific research. The NSF must return to a merit-based focus on legitimate science of the kind that resulted in landing Americans on the moon and making the U.S. technology industry the engine of the global economy.

If this analysis is correct, then I have no quarrel with the last paragraph, particularly the insistence that the NSF go back to “a merit-based focus on legitimate science”. America has long been a Mecca for scientists from foreign countries, many coming here to study, do research, or take faculty positions. This kind of funding, if continued, would seriously erode the nation’s scientific reputation. It’s already happened to New Zealand, but the “social justice” there involves incorporating “indigenous knowledge”, like Polynesian navigational astronomy, into modern science.

It is too late to stop the awokening of New Zealand’s science, but I’m pretty sure that the new Trump administration—if it doesn’t cut real science—will ameliorate the current trend. (Note: this is NOT an endorsement of Trump as President, but a hope that his admiinistration will fix the wrongly skewed direction of science funding.)

We collected some of the wildest physics that New Scientist covered in 2024, findings that are forcing scientists – and us – to rethink reality

We collected some of the wildest physics that New Scientist covered in 2024, findings that are forcing scientists – and us – to rethink reality

From Alzheimer's disease to depression to heart disease, Ozempic and other GLP-1 agonist drugs appear to offer a solution. Can one type of drug really tackle so many conditions, and if so, how does it actually work?

Astronomers spotted a 70-centimetre asteroid hours before it hit the atmosphere above northern Siberia, making a fireball in the sky

In a first-of-its-kind breakthrough, a team of researchers has developed an artificial adhesion system that closely mimics natural biological interactions. Their research focuses on understanding how cells physically interact with each other and their environment, with the ultimate goal of developing innovative tools for disease diagnosis and therapy.

NASA has given SpaceX the contract to launch the Dragonfly mission to Saturn’s moon Titan. A Falcon Heavy will send the rotorcraft and its lander on their way to Titan in 2028, if all goes according to plan, and the mission will arrive at Titan in 2034. Dragonfly is an astrobiology mission designed to measure the presence of different chemicals on the frigid moon.

Dragonfly will be the second craft to visit Titan, along with the Huygens probe and its short visit back in 2005.

Titan is remarkable because it’s the only body besides Earth with liquids on its surface. The liquids are hydrocarbons, not water, though there may be surface deposits of water ice from impacts or cryovolcanic eruptions. Researchers think that prebiotic chemicals are also present, making the moon an enticing target to understand how far prebiotic chemistry may have advanced.

These images of Titan’s well-known hydrocarbon seas are from Cassini radar data. Image Credit: [JPL-CALTECH/NASA, ASI, USGS]

Titan is benign when it comes to powered flight; its atmosphere is dense and its gravity is weak, compared to Earth. Dragonfly is an octocopter, a large quadcopter with double rotors, that can take advantage of Titan’s flight-friendly conditions. It will travel at about 36 kmh (22 mph) and will be powered by a Radioisotope Thermoelectric Generator (RTG), a type of engine proven in multiple missions. The craft is designed to be redundant; it can lose one of its motors or rotors and still function.

Dragonfly will land near a feature on Titan called Shangri-La, east of where the Huygens probe landed. Shangri-La is one of three large sand seas near the moon’s equator.

Dragonfly’s target is the Selk impact structure, near the edge of Shangri-La. Selk is a young impact crater about 90 km (56 mi) in diameter that features melt pools, sites where liquid water and organics could mix together to form amino acids or other biomolecules. Dragonfly will initially land at some dunes near the structure then begin exploring the region and its chemistry.

Thanks largely to Cassini and Huygens, researchers have made progress understanding Titan. In a 2020 paper, researchers examined two types of craters on the moon: dune craters and plains craters. Selk is a dune crater, and in the paper, researchers said that the dune craters are richer in organics than plains craters, and in fact are almost entirely composed of organics. However, Titan’s thick atmosphere makes it difficult to observe, and these findings stem from interpreting albedo and emissivity.

Selk and the other dune craters may have originally had more water ice, according to the research, but much of it’s been eroded away. However, there was a long period of time where the water ice was present, and Dragonfly is heading for Selk to examine the chemistry in the crater and to try and determine if water and organics interacted and if prebiotic chemistry made any headway.

It’s up to SpaceX’s Falcon Heavy to send Dragonfly on its way to Titan. Falcon Heavy has 11 launches under its belt, including the launch of the Europa Clipper in October. After Falcon Heavy launches Dragonfly, the spacecraft will perform one flyby of Earth to gain additional velocity.

It’ll take six years for Dragonfly to reach Titan, and just as it arrives, the entry capsule will separate from the cruise module. With the help of an aeroshell and two chutes, the lander will endure an approximately 105-minute descent. At approximately 1.2 km above the surface, the lander will deploy its skids, and based on its lidar and radar data, will perform and autonomous landing.

From its landing site, Dragonfly will deploy itself and perform a series of flights up to 8km (5 mi) long. There’s diverse geology in the region, and the rotorcraft will acquire samples and then analyze them during Titan’s nights, which last about 8 Earth days or about 192 hours. After that, it will head to the Selk crater.

Titan is an important astrobiology target in our Solar System, and unlike the frozen ocean moons Europa and Enceladus, there’s no added complexity of somehow working its way through thick ice before its potentially biological environment can be examined.

SpaceX’s Falcon Heavy rocket sends NASA’s Europa Clipper into space from its Florida launch pad. If all goes well, the Falcon Heavy will launch the Dragonfly mission to Titan in July, 2028. (NASA Photo / Kim Shiflett)

But for all of this to succeed, it needs a successful launch first. NASA is paying SpaceX about $256 million to launch Dragonfly, and it the launch goes off without a hitch, it’ll be money well-spent.

The post Dragonfly is Going to Titan on a Falcon Heavy appeared first on Universe Today.

The algorithms behind generative AI tools like DallE, when combined with physics-based data, can be used to develop better ways to model the Earth's climate. Computer scientists have now used this combination to create a model that is capable of predicting climate patterns over 100 years 25 times faster than the state of the art.

A group of young students became bonafide biomedical scientists before they even started high school. Through a partnership with a nearby university, the middle schoolers collected and analyzed environmental samples to find new antibiotic candidates. One unique sample, goose poop collected at a local park, had a bacterium that showed antibiotic activity and contained a novel compound that slowed the growth of human melanoma and ovarian cancer cells in lab tests.

Researchers explore the transformation dynamics of cubic liquid crystals using direct simulation and machine learning, offering new possibilities for advanced materials development.

Covid-19 emerged in 2019, but some questions are still unanswered as to its origins

Research is paving the way for advanced diamond-based technologies in electronics and quantum computing.

Research is paving the way for advanced diamond-based technologies in electronics and quantum computing.

A researcher has helped create a new 3D printing approach for shape-changing materials that are likened to muscles, opening the door for improved applications in robotics as well as biomedical and energy devices.

A researcher has helped create a new 3D printing approach for shape-changing materials that are likened to muscles, opening the door for improved applications in robotics as well as biomedical and energy devices.

A research team has taken inspiration from the brains of insects and animals for more energy-efficient robotic navigation.

A research team has taken inspiration from the brains of insects and animals for more energy-efficient robotic navigation.