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A seismic shift occurred in astronomy during the Scientific Revolution, beginning with 16th-century polymath Copernicus and his proposal that the Earth revolved around the Sun. By the 17th century, famed engineer and astronomer Galileo Galilei refined Copernicus’ heliocentric model using observations made with telescopes he built himself. However, it was not until Kepler’s observations that the planets followed elliptical orbits around the Sun (rather than circular orbits) that astronomical models matched observations of the heavens completely.

As it turns out, this very quirk of orbital mechanics may be essential to the emergence of life on planets like Earth. That was the hypothesis put forth in a recent study by a team of astronomers led by the University of Leeds. According to their work, orbital eccentricity (how much a planet’s orbit deviates from a circle) can influence a planet’s climate response, which could have a profound effect on its potential habitability. These findings could be significant for exoplanet researchers as they continue to search for Earth-like planets that could support life.

The team was led by Binghan Liu, a PhD Student in the School of Physics and Astronomy at the University of Leeds, who conducted the research as part of his thesis. He was joined by Daniel R. Marsh, the Priestley Chair in Comparative Planetary Atmospheres (and Liu’s thesis advisor), and other colleagues from Leeds and the Institute of Astronomy at the University of Cambridge. Their paper, “Eccentric orbits may enhance the habitability of Earth-like exoplanets,” was recently published in the Monthly Notices of the Royal Astronomical Society.

The idea of circular orbits has deep roots in Western astronomy, going all the way back to Classical Antiquity. Some examples include Plato and Aristotle, who argued that the then-known celestial bodies (the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn) were perfect spheres that orbited Earth in concentric circles. This belief endured well into the Scientific Revolution, with both Copernicus and Galileo arguing that the then-known planets (Mercury, Venus, the Earth and the Moon, Mars, Jupiter, and Saturn) orbited the Sun in concentric circles.

It was not until Johannes Kepler introduced the concept of elliptical orbits that scientists could match their astronomical models to the observed motions of the planets. Since then, scientists have learned a great deal about orbital parameters – such as semi-major axis (a), eccentricity (e), axial tilt (?), inclination (i), and periapsis – and how they can influence a planet’s climate over time. These parameters have also become very important for exoplanet studies, as they are vital to determining if a planet could be “potentially habitable.”

For their study, Liu and his colleagues used the Whole Atmosphere Community Climate Model (WACCM6), a high-top interactive Earth-system model capable of simulating conditions on Earth (from the oceans to the upper atmosphere) to simulate Earth-like exoplanets with two different orbital parameters. For one set, they assigned circular orbits (e = 0), while the others were assigned highly eccentric orbits (e = 0.4) – far greater than Earth’s eccentricity (0.016). They were also assigned zero obliquity (? = 0) and a fixed level of annual solar irradiance (aka. annual mean insolation).

After running 30 simulation years for each case, they examined how both groups of exoplanets behaved regarding their climate response. This included latitudinal and seasonal variations in their hydrological cycle (sea ice, land snow, and clouds) and land habitability metrics like surface temperature and precipitation. As they indicated in their paper, exoplanets within the highly eccentric orbit group had 25% more habitable land area for more than 80% of their orbit, with an average increase of 7% for their entire orbital cycle.

Artist’s illustration of Proxima Centauri b. ESO/M. Kornmesser

Naturally, there were some caveats and addendums that they were sure to include:

“It is important to note that the habitability of land depends on the chosen metric and the duration of time during which the conditions are met for a specific metric. We conclude that, under the same annual mean stellar flux, an Earth-analogue planet with zero-obliquity in a highly eccentric orbit around a Sun-like star may have enhanced land habitability compared to its circular counterpart.”

In other words, the simulations are based on planets with far more eccentric orbits than Earth and are not subject to the same changes in obliquity, which also profoundly impact Earth’s climate (i.e., glacial and inter-glacial periods). Nevertheless, their study demonstrates that planets with eccentric orbits are more likely to be habitable than those with circular orbits that experience little in the way of seasonal variations throughout the year. These results could have significant implications for exoplanet studies and the search for habitable worlds beyond the Solar System.

In addition, they note how astronomers will benefit from next-generation observatories that will be capable of spotting Earth-like exoplanets with eccentric orbits in the near future:

“The detection of highly eccentric terrestrial exoplanets is low due to the limitation of the current observation techniques, which are biased towards close-in and thus, tidally locked exoplanets in circular orbits. However, with the upcoming ground and space telescope missions such as PLATO, ELT, and HWO, more highly eccentric Earth-like rocky exoplanets may be revealed and characterized. Understanding the potential climate outcomes and habitability of highly eccentric rocky exoplanets remains a challenging task.”

Further Reading: MNRAS

The post Elliptical Orbits Could be Essential to the Habitability of Rocky Planets appeared first on Universe Today.

Nutrient-rich "dark earth" soil may store an amount of carbon nearly equivalent to annual CO2 emissions in the US, a finding that suggests the Amazon sequesters far more carbon than previously known

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Researchers are using mayonnaise to study and address the stability challenges of nuclear fusion by examining the phases of Rayleigh-Taylor instability. Their innovative approach aims to inform the design of more stable fusion capsules, contributing to the global effort to harness clean fusion energy. Their most recent paper explores the critical transitions between elastic and plastic phases in these conditions.

The world is going to need a lot of weird metals in the coming years, according to chemistry professor. But he isn't talking about lithium, cobalt or even beryllium. He's interested in dysprosium, which is so hidden in the periodic table that you'd be forgiven for thinking he made it up.

Researchers found that how well light-converting molecules stack together in a solid is important for how well they convert light into electric current. A rigid molecule that stacked well showed excellent electricity generation in an organic solar cell and photocatalyst, easily outperforming a similar flexible molecule that did not stack well. This new way of improving the design of molecules could be used to pioneer the next generation of light-converting devices.

Gold does not readily lend itself to being turned into long, thin threads. But researchers have now managed to create gold nanowires and develop soft electrodes that can be connected to the nervous system. The electrodes are soft as nerves, stretchable and electrically conductive, and are projected to last for a long time in the body.

The production of more than 90 percent of all chemical products we use in our everyday lives relies on catalysts. Catalysts speed up chemical reactions, can reduce the energy required for these processes, and in some cases, reactions would not be possible at all without catalysts. Researchers developed a concept that increases the stability of noble-metal catalysts and requires less noble metal for their production.

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Heat and pressure can deteriorate the properties of piezoelectric materials that make state-of-the-art ultrasound and sonar technologies possible -- and fixing that damage has historically required disassembling devices and exposing the materials to even higher temperatures. Now researchers have developed a technique to restore those properties at room temperature, making it easier to repair these devices -- and paving the way for new ultrasound technologies.

Can plasma be sufficiently heated inside a tokamak using only microwaves? New research suggests it can! Eliminating the central ohmic heating coil normally used in tokamaks will free up much-needed space for a more compact, efficient spherical tokamak.

Conventional clustering techniques often focus on basic features like crystal structure and elemental composition, neglecting target properties such as band gaps and dielectric constants. A new study introduced a machine learning-powered clustering model that incorporates both basic features and target properties, successfully grouping over 1,000 inorganic materials. This model provides insights into material relationships, potential applications, and identifies key factors to balance band gaps and dielectric constants, addressing their trade-off relationship.

Conventional clustering techniques often focus on basic features like crystal structure and elemental composition, neglecting target properties such as band gaps and dielectric constants. A new study introduced a machine learning-powered clustering model that incorporates both basic features and target properties, successfully grouping over 1,000 inorganic materials. This model provides insights into material relationships, potential applications, and identifies key factors to balance band gaps and dielectric constants, addressing their trade-off relationship.

A new study by seismologists reexamines earthquakes in the Permian Basin that occurred before 2017 against the real-time data collected from earthquakes taking place after 2020. Results confirm that the seismicity occurring from 2009-2017 was causally linked to the underground injection of wastewater that is a byproduct of oil and gas extraction.

A new material for flexible electronics could enable multilayered, recyclable electronic devices and help limit e-waste.

A new material for flexible electronics could enable multilayered, recyclable electronic devices and help limit e-waste.

That ‘Old Faithful’ of meteor showers the Perseids peak early next week.

Great ready for one of the surefire astronomical events of 2024, as the peak for the Perseid meteors arrives next week.

To be sure, the Perseids aren’t the most intense annual meteor shower of the year; in the first half of the 20th century, that title now goes to the December Geminids. What the Perseids do have going for them is timing: they typically arrive in early August, before the academic year starts and during prime camping season, which finds lots of folks out under warm summer skies.

Perseid Prospects for 2024

The Perseids are active across August, from July 14th to September 1st. In 2024, the shower is expected to display a broad peak, centered on the night of August 11-12th. Typically, we see a twin peak in activity from the shower, though we expect the 2024 peak to arrive around 3:00 Universal Time (UT) on the 12th. This puts the shower high in the sky for northern Europe at dawn. North America isn’t far behind.

Circumstances for the 2024 Perseids versus the Earth. Credit: Dave Dickinson

In 2024, the Moon will interfere somewhat, with a 44% illuminated waxing crescent phase setting around 11:30 PM local. During recent years, the Perseids have displayed a maximum rate of up to 150 per hour, coming off high perihelion rates of 500 per hour in the 1990s. In 2024, expect to see around 100 per hour.

The Perseids: A Backstory

The source of the Perseids is none other than periodic comet 109P Swift-Tuttle. On a 133 year orbit, the comet reaches perihelion again next century on July 12th, 2126. The approach radiant for the shower hails from the northern constellation of Perseus the Hero (near the star Eta Persei) hence the name. Though the comet was only discovered in the mid-19th century, knowledge of the shower stretches back to antiquity. The Perseids are known as the “Tears of Saint Lawrence,” after the Christian saint who was martyred on a hot grid-iron on August 10th, 258 AD. In Andalusian southern Spain, this name for the summer Perseids in still well-known.

A Perseid meteor burning up in the Earth’s atmosphere, as seen from the International Space Station. Credit: NASA Observing Meteors

Observing the Perseids is as simple as laying back, aiming your working set of ‘Mk-1 eyeballs’ at the sky, and waiting. A good alternate method of ‘hearing’ meteors is to tune an old school radio to an unoccupied section of the FM dial, and listening for meteor ‘pings’.

Two key factors come into play for a successful meteor watching expedition: watching at the correct time, under as dark a sky as possible. Don’t be afraid to start watching a few evenings prior this coming weekend. For the U.S. southeast, there’s always a good chance that Hurricane Debby could sweep out skies in its wake.

Looking to the northeast at 10PM local. Credit: Stellarium

For northern hemisphere observers, the radiant rises around 10 PM local. It will be high in the sky to the northeast around local midnight. This means that you’ll start seeing meteors from the Perseids in the late evening after sunset. Rates will really pick up after midnight, as you turn forward into the stream. You’re seeing ancient streams of cometary dust laid down by Swift-Tuttle, intersecting the 12,750 kilometer-wide tunnel carved out by the Earth. The Perseids have a respectable incoming relative velocity of 59 kilometers per second.

Though it may not seem it, even the largest, most brilliant Perseid meteors are the result of pea-sized grains. These are burning up in the Earth’s atmosphere about 80 to 120 kilometers overhead. Keep a pair of binoculars handy, to examine any lingering persistent smoke trains.

2023 Perseids over Yuzhno-Morskoy, Russia. Credit: Filipp Romanov ‘Hearing’ Meteors

Also, keep an ear out for any hissing audible meteors. This bizarre phenomenon was long thought to be a myth, or at most, a psychological phenomenon. There’s now good evidence that meteors do transmit a corresponding radio emission that can be ‘heard’ near the observer. This effect is known as electrophonic sound. Powerful auroras are thought to produce a similar effect.

Imaging the Perseids or any meteor shower is as simple as aiming a tripod mounted DSLR camera at a section of the sky and taking long exposure shots. Use as wide a field of view aperture lens as you can. Then, take a series of test shots to get the ISO/f-stop/exposure time correct for current conditions. An intervalometer is an invaluable tool for this, as you can simply program it to take a series of exposures, then turn it loose while you sit back and enjoy the show.

Finally, don’t forget to report what you see. When it comes to meteor showers, astronomers need all the data they can get. Simply count how many meteors you see in a given span of time, and report it to the International Meteor Organization (IMO).

Don’t miss a chance to get out under warm summer skies this coming week, and catch the 2024 Perseid meteors.

The post 2024 Perseids Light Up the August Sky appeared first on Universe Today.

From artificial retinas to ageing mice, here are five of the most promising results from research performed on the ISS – and what they might mean for humans on Earth and in space

An arm bone from an ancient human that lived 700,000 years ago on the island of Flores is the smallest ever found from an adult hominin, adding a new piece to the puzzle of Homo floresiensis

The International Space Station will burn up and splash down into the Pacific sometime around 2030. What could possibly go wrong? And will we ever see anything like the ISS again?