View of Didymos, Dimorphos, and the plume coming off of Dimorphos after the Double Asteroid Redirect Test, or DART mission, purposefully made impact, in this image acquired by ASI’s LICIACube satellite just before its closest approach to the Dimorphos asteroid, September 26, 2022.
| Photo Credit: Reuters

Launched in 2011, NASA’s NEOWISE mission operated in Earth’s orbit until late last week. It detected more than 3,000 near-Earth objects or NEOs – asteroids or comets whose orbits can bring them close to Earth, even with the possibility of a collision. NEOWISE was shut down on August 8.

Surveying the population of NEOs is central to the emerging concept of planetary defence. That is, understanding and mitigating the risk of collision from asteroids large enough to do significant damage to Earth.

NEOWISE has made fundamental contributions to establishing the knowledge base for planetary defence, with more than 200 of the 3,000 objects it studied not known to us previously.

Now at mission end, and commanded by NASA to shut itself down, NEOWISE will re-enter Earth’s atmosphere before the end of this year. Where does that leave us with defending our planet?

From astrophysics to planetary defence

NEOWISE started life as a different mission, simply called WISE (Wide-field Infrared Survey Explorer). It was designed to study the infrared radiation from distant galaxies in the universe.

Infrared means “beyond red” – infrared light sits just past the red end of the spectrum of colours humans can see. We know infrared radiation better as the heat from the Sun, for example, or from a radiator keeping us warm in winter.

When the coolant on the WISE mission ran out and these sensitive observations of galaxies couldn’t be carried out any more, NASA granted a mission extension under the NEOWISE name. They realised the telescope system was still sensitive enough to detect asteroids and comets that come close to Earth and the Sun, thereby having a very strong infrared signal.

NASA has an extraordinary history of squeezing extra life out of missions that reach completion. In this case, NEOWISE represented an entire second life, in an entirely different area of research.

How will we defend Earth now?

As well as the discovery and study of thousands of NEOs, NEOWISE established the foundation of knowledge that has informed a new, dedicated planetary defence mission. NASA’s NEO Surveyor will be launched in 2027.

NEO Surveyor’s goal is to discover approximately two thirds of all NEOs larger than 140 metres in diameter, over a five year baseline survey. This is a big step toward fulfilling the mandate United States Congress has provided to NASA: to discover 90% of all NEOs in this size range.

If they hit Earth, asteroids of this size could cause mass casualties if the impact were over a large metropolitan region.

You might think this poses a bit of a risk – shutting down NEOWISE three years before launching NEO Surveyor. What happens if one of these big asteroids comes our way in the next few years?

The risks are very small, as estimates show asteroids 140 metres in diameter impact Earth only approximately every 20,000 years. So, we would have to be extremely unlucky to have one in any given three-year period, especially impacting a place that would cause a large amount of damage. Only around 3% of Earth’s surface is occupied by urban areas.

NASA doesn’t really have much of a choice with the end of NEOWISE. The Sun’s 11-year activity cycle is picking up and causing Earth’s upper atmosphere, the ionosphere, to thicken. NEOWISE is flying through this ionosphere and can’t raise its orbit, so the ionosphere is inevitably dragging NEOWISE back to Earth.

NEO Surveyor started construction in 2023, so a 2027 launch is pretty impressively rapid, which is minimising the gap between NEOWISE and NEO Surveyor.

NEOWISE is scheduled to enter Earth’s atmosphere before the end of the year, but we don’t know precisely when.

Weighing almost 700kg, some of NEOWISE itself is likely to impact the surface of Earth. Hopefully it stays away from populated areas in the process – some recent re-entry events have resulted in space debris falling reasonably close to populated areas.

An asteroid is coming! What next?

Knowing about an asteroid on a collision course with Earth is one thing. Doing something about it is another thing altogether.

Huge steps toward planetary defence occurred two years ago, when the DART mission flew to an asteroid, impacted it, and changed its trajectory. This demonstrated it’s possible to change the course of asteroids, which could be used in the future to protect Earth from a collision.

Predicting potential Earth impacts as far as possible in advance, years preferably, gives the DART-style technology approach a chance.

The pioneering work of NEOWISE, and the upcoming comprehensive observations of NEO Surveyor, will place an enormous amount of information in our scientific bank, which will never go out of date and will be the basis for planetary defence for perhaps hundreds of years into the future.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

An artist’s illustration shows the nearest brown dwarf to Earth. ESO-I. Crossfield-N.
| Photo Credit: Reuters

The weather report is in for the two brown dwarfs – celestial bodies bigger than a planet but smaller than a star – closest to us. It is inclement, to put it mildly: blazingly hot, with a toxic chemical cocktail swirling in the atmosphere and clouds of silicate particles blowing around like a Saharan dust storm.

Researchers have used James Webb Space Telescope observations to conduct detailed examinations of the atmospheric conditions on brown dwarfs, specifically a pair that orbit each other around six light years from Earth, quite close by cosmic standards. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).

The Webb data provided a three-dimensional look at how the weather changed over the course of a brown dwarf’s rotation – the larger of the two taking seven hours and the smaller five hours – with multiple layers of clouds found at different atmospheric depths.

Both have atmospheres dominated by hydrogen and helium, with trace amounts of water vapor, methane and carbon monoxide. The temperature at their cloud tops was about 1,700 degrees Fahrenheit (925 degrees Celsius), similar to a candle flame.

“In this study, we created the most detailed ‘weather maps’ for any brown dwarf to date,” said astronomer Beth Biller of the University of Edinburgh’s Institute for Astronomy, lead author of the study published on Monday in the scientific journal Monthly Notices of the Royal Astronomical Society.

Brown dwarfs are neither a star nor a planet, but something in between. They give off their own light thanks to their sheer heat – “just like you would see embers in a fire glowing red because of how hot they are,” Biller said. It was that light that the researchers observed with Webb. Unlike stars, brown dwarfs do not have nuclear fusion occurring at their core.

“Like planets, but unlike stars, brown dwarfs can also have clouds made out of precipitates in their atmospheres. However, while we have water clouds on Earth, the clouds on brown dwarfs are much hotter and likely made up of hot silicate particles -kind of like a very hot Saharan dust storm,” Biller said.

The current scientific thinking is that brown dwarfs form from large clouds of gas and dust like stars do, but fall short of mass sufficient to ignite nuclear fusion. Their composition is similar to gas giant planets like Jupiter, our solar system’s largest planet. Their mass is up to 80 times greater than Jupiter’s. By comparison, the sun’s mass is about 1,000 times greater than Jupiter’s.

The two brown dwarfs examined by Webb formed about 500 million years ago. Each has a diameter comparable to Jupiter’s. One is 35 times more massive than Jupiter, and the other 30 times.

Webb discerned how their light varied as different atmospheric features rotated in and out of view.

“The fast rotation of both objects helps to drive their weather patterns, and if you could actually directly see the cloud-top structure, you probably would be able to see bands and vortices, like the Great Red Spot, as you do on Jupiter,” Biller said.

“In the future, similar techniques could be used to study weather on potentially habitable exoplanets,” Biller added, referring to planets beyond our solar system.

Brown dwarfs are relatively common. About 1,000 are known, compared to more than 5,000 known exoplanets.

Webb examines the cosmos mainly in the infrared, while its Hubble Space Telescope predecessor does so primarily at optical and ultraviolet wavelengths.

“The atmospheres of brown dwarfs are highly complex. Webb provides a huge leap forward in our ability to understand these atmospheres by providing unprecedented wavelength range and sensitivity,” said astronomer and study co-author Johanna Vos of Trinity College Dublin in Ireland.

“These different wavelengths allow us to monitor the atmosphere from very deep to very shallow, giving a comprehensive look at the full extent of the atmosphere,” Vos added.

This artist’s concept envisions what hydrocarbon ice forming on a liquid hydrocarbon sea of Saturn’s moon Titan might look like in this NASA image released on January 8, 2013.
| Photo Credit: Reuters

NASA’s Cassini spacecraft, which explored Saturn and its icy moons, including the majestic Titan, ended its mission with a death plunge into the giant ringed planet in 2017. But some of the voluminous data gathered by Cassini during its 13 years of surveying the Saturnian system is only now being fully examined.

Cassini’s radar observations are providing intriguing new details about the seas of liquid hydrocarbons on the surface of Titan, our solar system’s second-largest moon and a place of interest in the search for life beyond Earth.

Titan, shrouded in a smog-like orange haze, is the only known world other than Earth exhibiting liquid seas on the surface, though they are not composed of water but rather nitrogen and the organic compounds methane and ethane, components of natural gas.

The study involved three seas near Titan’s north pole: Kraken Mare, the largest, covering an area comparable to Eurasia’s Caspian Sea; Ligeia Mare, the second-largest and comparable in area to North America’s Lake Superior; and Punga Mare, roughly equivalent to Africa’s Lake Victoria.

The chemical composition of these seas – methane-rich versus ethane-rich – was found to vary depending on their latitude. The study also documented the extent and distribution of sea surface ripples, indicating active tidal currents and increased roughness near estuaries – the mouths of rivers.

Titan, 3,200 miles (5,150 km) wide, is our solar system’s second-biggest moon behind Jupiter’s Ganymede and is larger than the planet Mercury. Titan and Earth are the only worlds in the solar system where liquids rain down from clouds, flow as rivers into seas and lakes on the surface and evaporate back up to the sky to begin the hydrological process again.

On Earth, water rains down from clouds. On Titan, clouds spew methane – which is a gas on Earth – in liquid form due to the frigid climate.

“Titan is really an Earth-like world with a diverse set of very familiar surface morphologies shaped by a methane-based hydrologic system operating in a dense nitrogen atmosphere,” said Cornell University engineer and a planetary scientist Valerio Poggiali, lead author of the study published on Tuesday in the journal Nature Communications.

“Seas and lakes of liquid hydrocarbons dot the surface in the polar regions, especially the northern one. Precipitation-fed channels flow into these seas creating estuaries, in some cases deltas,” Poggiali added.

The Cassini data indicated the rivers carry pure liquid methane that then mixes into the more ethane-rich liquids of the seas, much as freshwater in Earth’s rivers mixes into saltwater oceans.

“Titan’s seas are pulled by Saturn’s massive gravity, just like our seas, and the tidal range on some of its shorelines may be around a foot (30 cm). Because the tidal period – Titan’s day – is long, 16 Earth days, the tidal cycle is slow, so the tidal currents are generally weak,” said planetary scientist and study co-author Ralph Lorenz of the Johns Hopkins University Applied Physics Laboratory.

The study used “bistatic” radar data collected during Cassini flybys of Titan, three in 2014 and one in 2016. Cassini aimed a radio beam at targets on Titan’s surface, which then reflected toward a receiving antenna on Earth. This provided richer information about the composition of the reflecting surface and its roughness than ordinary Cassini “monostatic” radar, which bounces a radio signal off a target and back to the point of origin.

“This is likely the last untouched dataset that the Cassini spacecraft left us,” Poggiali said.

Titan boasts environments with conditions considered potentially suitable for life. For instance, Titan appears to harbor a vast subsurface ocean of liquid water.

“Are the heavy organic molecules produced in Titan’s atmosphere prebiotic in nature?” Poggiali asked, referring to chemistry that could led to formation of life. “Has all this organic material ever been in contact with liquid water? We believe that similar interactions could have led to the origin of life on our planet, with the generation of molecules able to produce energy or store information.”

A model of Chinese Mars rover Zhurong, part of China’s Tianwen-1 space mission, is seen displayed at the China International Aviation and Aerospace Exhibition, or Airshow China, in Zhuhai, Guangdong province, China September 28, 2021.
| Photo Credit: Reuters

Scientists have identified a super resilient desert moss species in China’s western region of Xinjiang that could help sustain possible colonies on Mars, a study by the Chinese Academy of Sciences showed.

When subjected to conditions that simulate the environment on Mars, the moss – Syntrichia Caninervis – was found to be able to withstand extreme dryness, ultra-low temperatures and radiation, the academy said in a research paper published in The Innovation journal last week.

The moss could serve as the “basis for the establishment and maintenance of the ecosystem by contributing to oxygen production, carbon sequestration, and soil fertility”, the researched said in the study, published on July 1.

“(It) can help drive the atmospheric, geological, and ecological processes required for other higher plants and animals while facilitating the creation of new habitable environments conducive to long-term human settlement,” the paper added.

In the research, scientists found that even after losing more than 98% of its cellular water content, the moss was able to recover photosynthetic and physiological activities within seconds after it was hydrated.

When intact, the plant can also tolerate ultra-low temperatures and regenerate after being stored in a freezer at minus 80 degree Celsius (minus 112 Fahrenheit) for five years or in liquid nitrogen for a month.

The moss is found in Xinjiang, Tibet, a Californian desert, the Middle East and polar regions.

The race to place a larger footprint in space has spurred China and the United States to launch exploration plans in recent years.

Chinese missions include launching near-Earth asteroid probe Tianwen-2 next year, and Tianwen-3 around 2030 to bring samples back from Mars. China last month retrieved samples from the far side of the moon.

In the United States, NASA has formulated a 20-year plan for Mars, seeking answers to whether the red planet is habitable for humans.

An artist’s concept of the planet HD 189733 b located 64 light-years from Earth.
| Photo Credit: Reuters

The planet known as HD 189733b, discovered in 2005, already had a reputation as a rather extreme place, a scorching hot gas giant a bit larger than Jupiter that is a striking cobalt blue colour and has molten glass rain that blows sideways in its fierce atmospheric winds. So how can you top that?

Add hydrogen sulfide, the chemical compound behind the stench of rotten eggs. Researchers said on Monday new data from the James Webb Space Telescope is giving a fuller picture of HD 189733b, already among the most thoroughly studied exoplanets, as planets beyond our solar system are called. A trace amount of hydrogen sulfide was detected in its atmosphere, a first for any exoplanet.

“Yes, the stinky smell would certainly add to its already infamous reputation. This is not a planet we humans want to visit, but a valuable target for furthering our understanding of planetary science,” said astrophysicist Guangwei Fu of Johns Hopkins University in Baltimore, lead author of the study published in the journal Nature.

It is a type called a “hot Jupiter” – gas giants similar to the largest planet in our solar system, only much hotter owing to their close proximity to their host stars. This planet orbits 170 times closer to its host star than Jupiter does to the sun. It completes one orbit every two days as opposed to the 12 years Jupiter takes for one orbit of the sun.

In fact, its orbit is 13 times nearer to its host star than our innermost planet Mercury is to the sun, leaving the temperature on the side of the planet facing the star at about 1,700 degrees Fahrenheit (930 degrees Celsius).

“They are quite rare,” Fu said of hot Jupiters. “About less than one in 100 star systems have them.”

This planet is located 64 light-years from Earth, considered in our neighbourhood within the Milky Way galaxy, in the constellation Vulpecula. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).

“The close distance makes it bright and easy for detailed studies. For example, the hydrogen sulfide detection reported here would be much more challenging to make on other faraway planets,” Fu said.

The star it orbits is smaller and cooler than the sun, and only about a third as luminous. That star is part of a binary system, meaning it is gravitationally bound to another star.

Webb, which became operational in 2022, observes a wider wavelength range than earlier space telescopes, allowing for more thorough examinations of exoplanet atmospheres.

“Our research finds that HD 189733b is more similar to Jupiter than previously known,” Arizona State University astrophysicist and study co-author Luis Welbanks said. “This planet is very much like Jupiter, but just hotter.”

Jupiter, too, has trace amounts of hydrogen sulfide in its atmosphere. This planet is about 10% larger than Jupiter in diameter and mass.

In addition to detecting hydrogen sulfide, a sulfur-containing molecule, Webb observations showed that this planet has water and carbon dioxide in its atmosphere, as earlier data also indicated.

“With these three molecules, we are able to count the amount of oxygen, carbon and sulfur the planet has, giving us an opportunity to understand how the planet may have formed and whether it is different or not to the planets in our solar system,” Welbanks said.

The Webb observations also ruled out the presence of methane in the planet’s atmosphere.

“Understanding the composition of this and other exoplanets allows us to understand how unique our own solar system is and helps us place our existence in context,” Welbanks added.

“While we are not searching for life on HD 189733b – it is too hot, made up mostly of hydrogen and helium, it’s not like Earth, et cetera – understanding its atmosphere allows us to understand how physics and chemistry behave under different environments and to begin to put together the ‘recipe’ for forming planets.”

This China National Space Administration (CNSA) handout image released by Xinhua News Agency, shows the lander-ascender combination of Chang’e-6 probe taken by a mini rover after it landed on the moon surface, June 4, 2024. China’s Chang’e 6 probe returned on Earth on Tuesday with rock and soil samples from the little-explored far side of the moon in a global first. The probe landed in northern China on Tuesday afternoon in the Inner Mongolian region.
| Photo Credit: AP

The 2020s have already seen many lunar landing attempts, although several of them have crashed or toppled over. With all the excitement surrounding the prospect of humans returning to the Moon, both commercial interests and scientists stand to gain.

The Moon is uniquely suitable for researchers to build telescopes they can’t put on Earth because it doesn’t have as much satellite interference as Earth, nor a magnetic field blocking out radio waves. But only recently have astronomers like me started thinking about potential conflicts between the desire to expand knowledge of the universe on one side and geopolitical rivalries and commercial gain on the other, and how to balance those interests.

As an astronomer and the co-chair of the International Astronomical Union’s working group Astronomy from the Moon, I’m on the hook to investigate this question.

Everyone to the south pole

By 2035 – just 10 or so years away – American and Chinese rockets could be carrying humans to long-term lunar bases.

Both bases are planned for the same small areas near the south pole because of the near-constant solar power available in this region and the rich source of water that scientists believe could be found in the Moon’s darkest regions nearby.

Unlike the Earth, the Moon is not tilted relative to its path around the Sun. As a result, the Sun circles the horizon near the poles, almost never setting on some crater rims. There, the never-setting Sun casts long shadows over nearby craters, hiding their floors from direct sunlight for the past 4 billion years, 90% of the age of the solar system.

These craters are basically pits of eternal darkness. And it’s not just dark down there, it’s also cold: below -418 degrees Fahrenheit (-250 degrees Celsius). It’s so cold that scientists predict that water in the form of ice at the bottom of these craters – likely brought by ancient asteroids colliding with the Moon’s surface – will not melt or evaporate away for a very long time.

Surveys from lunar orbit suggest that these craters, called permanently shadowed regions, could hold half a billion tons of water.

The constant sunlight for solar power and proximity to frozen water makes the Moon’s poles attractive for human bases. The bases will also need water to drink, wash up and grow crops to feed hungry astronauts. It is hopelessly expensive to bring long-term water supplies from Earth, so a local watering hole is a big deal.

Telescopes on the Moon

For decades, astronomers had ignored the Moon as a potential site for telescopes because it was simply infeasible to build them there. But human bases open up new opportunities.

The radio-sheltered far side of the Moon, the part we never see from Earth, makes recording very low frequency radio waves accessible. These signals are likely to contain signatures of the universe’s “Dark Ages,” a time before any stars or galaxies formed.

Astronomers could also put gravitational wave detectors at the poles, since these detectors are extraordinarily sensitive, and the Moon’s polar regions don’t have earthquakes to disturb them as they do on Earth.

A lunar gravitational wave detector could let scientists collect data from pairs of black holes orbiting each other very closely right before they merge. Predicting where and when they will merge tells astronomers where and when to look for a flash of light that they would otherwise miss. With those extra clues, scientists could learn how these black holes are born and how they evolve.

The cold at the lunar poles also makes infrared telescopes vastly more sensitive by shifting the telescopes’ black body radiation to longer wavelengths. These telescopes could give astronomers new tools to look for life on Earth-like planets beyond the solar system.

And more ideas keep coming. The first radio antennae are scheduled to land on the far side next year.

Conflicting interests

But the rush to build bases on the Moon could interfere with the very conditions that make the Moon so attractive for research in the first place. Although the Moon’s surface area is greater than Africa’s, human explorers and astronomers want to visit the same few kilometer-sized locations.

But activities that will help sustain a human presence on the Moon, such as mining for water, will create vibrations that could ruin a gravitational wave telescope.

Also, many elements found on the Moon are extremely valuable back on Earth. Liquid hydrogen and oxygen make precious rocket propellant, and helium-3 is a rare substance used to improve quantum computers.

But one of the few places rich in helium-3 on the Moon is found in one of the most likely places to put a far-side, Dark Ages radio telescope.

Finally, there are at least two internet and GPS satellite constellations planned to orbit the Moon a few years from now. Unintentional radio emissions from these satellites could render a Dark Ages telescope useless.

The time is now

But compromise isn’t out of the question. There might be a few alternative spots to place each telescope.

In 2024, the International Astronomical Union put together the working group Astronomy from the Moon to start defining which sites astronomers want to preserve for their work. This entails ranking the sites by their importance for each type of telescope and beginning to talk with a key United Nations committee. These steps may help astronomers, astronauts from multiple countries and private interests share the Moon.

This article is republished from The Conversation under a Creative Commons license.

A computer-generated 3D model of Venus’ surface provided by NASA’s Jet Propulsion Laboratory shows the volcano Sif Mons which is exhibiting signs of ongoing activity, in this undated handout image. Using data from NASA’s Magellan mission, Italian researchers detected evidence of an eruption while the spacecraft orbited the planet in the early 1990s.
| Photo Credit: Reuters

Venus appears to be more volcanically active than previously known, according to scientists whose new analysis of decades-old radar images has spotted evidence of eruptions at two additional sites on the surface of Earth’s inhospitable planetary neighbour.

Radar images obtained by NASA’s Magellan spacecraft from 1990 to 1992 indicated large lava flows at these two locations in the Venusian northern hemisphere at the time of the observations, the researchers said. These findings, coupled with previous studies, indicate that the planet’s volcanic activity is comparable to Earth’s, they added.

Magellan mapped 98% of the Venusian surface. Advances in computing capability have made analyzing Magellan’s radar data easier in recent years.

“These findings significantly change our understanding of the degree to which Venus is volcanically active, suggesting it could be much more active than previously thought,” said planetary scientist Davide Sulcanese of d’Annunzio University in Pescara, Italy, lead author of the study published this week in the journal Nature Astronomy.

One of the two sites is a volcano called Sif Mons, which is about 200 miles (300 km) wide and situated in a region called Eistla Regio. The before-and-after radar images indicate a lava flow amounting to about 12 square miles (30 square km) of rock. The other site is a large volcanic plain in a region called Niobe Planitia. About 17 square miles (45 square kilometers) of rock was produced in this lava flow.

“Both Sif Mons and the volcanoes in Niobe Planitia are shield volcanoes, characterized by broad, gentle slopes formed by low-viscosity lava flows,” said d’Annunzio University planetary scientist and study co-author Giuseppe Mitri.

The new rock at both locations was estimated to have an average depth between about 10 and 66 feet (three and 20 meters).

“The lava flows observed along the western flank of Sif Mons exhibit linear features with sinuous patterns that follow the direction of the maximum slope, generally towards the west,” said planetary scientist and study co-author Marco Mastrogiuseppe of University Sapienza in Rome and Link Campus University in Rome.

“Regarding the flows in Niobe Planitia, the lava flows appear to originate near small shield volcanoes and extend towards the northeast, also following the direction of the slope,” Mastrogiuseppe added.

Venus is the second planet from the sun, and Earth the third. Venus has a diameter of about 7,500 miles (12,000 km), slightly smaller than Earth.

The new study builds on previous findings of ongoing Venusian volcanic activity. A 2023 study found that a volcanic vent on Maat Mons in a region called Atla Regio, near the equator, expanded and changed shape during the Magellan mission.

“Our study is the first to provide direct proof of lava flows formed during the Magellan mission period. By analyzing radar images from the Magellan spacecraft, we observed changes in surface morphology and radar data indicative of new lava flows,” Sulcanese said.

“This offers direct evidence of ongoing volcanic activity on Venus, building upon previous evidence such as atmospheric sulfur dioxide variations, surface thermal emissions data, and especially the evidence of deformation of a volcanic vent observed in Atla Regio,” Sulcanese said.

Studying volcanic activity provides a fuller understanding of a planet’s internal heat and geological processes.

“It provides insights into the planet’s thermal evolution, surface renewal processes and atmospheric interactions,” Mitri said.

The thick Venusian atmosphere, mainly carbon dioxide, traps in heat in a runaway greenhouse effect, making Venus our solar system’s hottest planet.

“Despite Venus and Earth being very similar in terms of size, mass, chemical composition and internal structure, there are fundamental differences that make Venus an infernal planet,” with a roasting surface temperature and crushing atmospheric pressure, Sulcanese said.

“The reason for this different evolution is still a subject of debate,” Sulcanese added, noting that planned NASA and European Space Agency missions in the coming years “will help us better understand why these two planets have met such different fates.”

The sun sets over the mountains, as a geomagnetic storm continues hitting the Earth, in Ronda, Spain, May 12, 2024.
| Photo Credit: Reuters

New research indicates the sun’s magnetic field originates much closer to the surface than previously thought, a finding that could help predict periods of extreme solar storms like the ones that slammed Earth earlier this month.

The magnetic field appears to generate 20,000 miles (32,000 kilometers) beneath the sun’s surface. Previous calculations put the roots of this process more than 130,000 miles (209,000 kilometers) below, an international team reported Wednesday.

The sun’s intense magnetic energy is the source of solar flares and eruptions of plasma known as coronal mass ejections. When directed toward Earth, they can create stunning auroras but also disrupt power and communications.

“We still don’t understand the sun well enough to make accurate predictions” of space weather, lead author Geoffrey Vasil of the University of Edinburgh said in an email.

The latest findings published in the journal Nature “will be an important step toward finally resolving” this mysterious process known as solar dynamo, added co-author Daniel Lecoanet of Northwestern University.

Galileo was among the first astronomers to turn a telescope skyward and study sunspots, back in the early 1600s. Solar flares and coronal mass ejections tend to occur near sunspots, dark patches as big as Earth that are located near the most intense portions of the sun’s shifting magnetic field.

Vasil and his team developed new models of the interaction between the sun’s magnetic field and the flow of plasma, which varies at different latitudes during an 11-year cycle. They fed their calculations into a NASA supercomputer in Northern California — the same one used in the 2015 movie “The Martian” to verify the best flight path to rescue the main character. The results suggested a shallow magnetic field and additional research is needed to confirm this.

The modeling was “highly simplified,” University of Wisconsin-Madison’s Ellen Zweibel, who was not part of the team, said in an accompanying editorial.

The results are intriguing and “sure to inspire future studies,” Zweibel said.

The new knowledge should improve long-term solar forecasts, allowing scientists to better predict the strength of our star’s future cycles. The sun is approaching its peak level of activity in the current 11-year cycle, thus the recent flareups.

Strong solar flares and outbursts of billions of tons of plasma earlier this month unleashed severe solar storms that produced auroras in unexpected places. Last week, the sun spewed out the biggest solar flare in almost 20 years, but it steered clear of Earth.

Better understanding of the sun can ensure “we are prepared for when the next storm — potentially much more dangerous — hits Earth,” Lecoanet said.

A false-color image obtained by the James Webb Space Telescope (JWST) shows the galaxy JADES-GS-z7-01-QU, the universeÕs earliest-known “dead” galaxy, a galaxy that has stopped star formation, in this undated handout picture obtained by Reuters.
| Photo Credit: Reuters

The James Webb Space Telescope, or JWST for short, is one of the most advanced telescopes ever built. Planning for JWST began over 25 years ago, and construction efforts spanned over a decade. It was launched into space on Dec. 25, 2021, and within a month arrived at its final destination: 930,000 miles away from Earth. Its location in space allows it a relatively unobstructed view of the universe.

The telescope design was a global effort, led by NASA, and intended to push the boundaries of astronomical observation with revolutionary engineering. Its mirror is massive – about 21 feet (6.5 meters) in diameter. That’s nearly three times the size of the Hubble Space Telescope, which launched in 1990 and is still working today.

It’s a telescope’s mirror that allows it to collect light. JWST’s is so big that it can “see” the faintest and farthest galaxies and stars in the universe. Its state-of-the-art instruments can reveal information about the composition, temperature and motion of these distant cosmic objects.

As an astrophysicist, I’m continually looking back in time to see what stars, galaxies and supermassive black holes looked like when their light began its journey toward Earth, and I’m using that information to better understand their growth and evolution. For me, and for thousands of space scientists, the James Webb Space Telescope is a window to that unknown universe.

Just how far back can JWST peer into the cosmos and into the past? About 13.5 billion years.

Time travel

A telescope does not show stars, galaxies and exoplanets as they are right now. Instead, astronomers are catching a glimpse of how they were in the past. It takes time for light to travel across space and reach our telescopes. In essence, that means a look into space is also a trip back in time.

This is even true for objects that are quite close to us. The light you see from the Sun left it about 8 minutes, 20 seconds earlier. That’s how long it takes for the Sun’s light to travel to Earth.

You can easily do the math on this. All light – whether sunlight, a flashlight or a light bulb in your house – travels at 186,000 miles (almost 300,000 kilometers) per second. That’s just over 11 million miles (about 18 million kilometers) per minute. The Sun is about 93 million miles (150 million kilometers) from Earth. That comes out to about 8 minutes, 20 seconds.

But the farther away something is, the longer its light takes to reach us. That’s why the light we see from Proxima Centauri, the closest star to us aside from our Sun, is 4 years old; that is, it’s about 25 trillion miles (approximately 40 trillion kilometers) away from Earth, so that light takes just over four years to reach us. Or, as scientists like to say, four light years.

Most recently, JWST observed Earendel, one of the farthest stars ever detected. The light that JWST sees from Earendel is about 12.9 billion years old.

The James Webb Space Telescope is looking much farther back in time than previously possible with other telescopes, such as the Hubble Space Telescope. For example, although Hubble can see objects 60,000 times fainter than the human eye is able, the JWST can see objects almost nine times fainter than even Hubble can.

The Big Bang

But is it possible to see back to the beginning of time?

The Big Bang is a term used to define the beginning of our universe as we know it. Scientists believe it occurred about 13.8 billion years ago. It is the most widely accepted theory among physicists to explain the history of our universe.

The name is a bit misleading, however, because it suggests that some sort of explosion, like fireworks, created the universe. The Big Bang more closely represents the appearance of rapidly expanding space everywhere in the universe. The environment immediately after the Big Bang was similar to a cosmic fog that covered the universe, making it hard for light to travel beyond it. Eventually, galaxies, stars and planets started to grow.

That’s why this era in the universe is called the “cosmic dark ages.” As the universe continued to expand, the cosmic fog began to rise, and light was eventually able to travel freely through space. In fact, a few satellites have observed the light left by the Big Bang, about 380,000 years after it occurred. These telescopes were built to detect the splotchy leftover glow from the Big Bang, whose light can be tracked in the microwave band.

However, even 380,000 years after the Big Bang, there were no stars and galaxies. The universe was still a very dark place. The cosmic dark ages wouldn’t end until a few hundred million years later, when the first stars and galaxies began to form.

The James Webb Space Telescope was not designed to observe as far back as the Big Bang, but instead to see the period when the first objects in the universe began to form and emit light. Before this time period, there is little light for the James Webb Space Telescope to observe, given the conditions of the early universe and the lack of galaxies and stars.

Peering back to the time period close to the Big Bang is not simply a matter of having a larger mirror – astronomers have already done it using other satellites that observe microwave emission from very soon after the Big Bang. So, the James Webb Space Telescope observing the universe a few hundred million years after the Big Bang isn’t a limitation of the telescope. Rather, that’s actually the telescope’s mission. It’s a reflection of where in the universe we expect the first light from stars and galaxies to emerge.

By studying ancient galaxies, scientists hope to understand the unique conditions of the early universe and gain insight into the processes that helped them flourish. That includes the evolution of supermassive black holes, the life cycle of stars, and what exoplanets – worlds beyond our solar system – are made of.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

An artist’s concept shows the exoplanet 55 Cancri e, also called Janssen, a so-called super-Earth, a rocky planet significantly larger than Earth but smaller than Neptune, along with the star it orbits in this undated illustration released by NASA.
| Photo Credit: Reuters

Astronomers have searched for years for rocky planets beyond our solar system with an atmosphere – a trait considered essential for any possibility of harbouring life. Well, they finally seem to have located one. But this hellish planet – apparently with a surface of molten rock – offers no hope for habitability.

Researchers said on Wednesday the planet is a “super-Earth” – a rocky world significantly larger than our planet but smaller than Neptune – and it orbits perilously close to a star dimmer and slightly less massive than our sun, rapidly completing an orbit every 18 hours or so.

Infrared observations using two instruments aboard the James Webb Space Telescope indicated the presence of a substantial – if inhospitable – atmosphere, perhaps continuously replenished by gases released from a vast ocean of magma.

“The atmosphere is likely rich in carbon dioxide or carbon monoxide, but can also have other gases such as water vapor and sulfur dioxide. The current observations cannot pinpoint the exact atmospheric composition,” said planetary scientist Renyu Hu of NASA’s Jet Propulsion Laboratory and Caltech, lead author of the study published in the journal Nature.

The Webb data also did not make clear the thickness of the atmosphere. Hu said it could be as thick as Earth’s or even thicker than that of Venus, whose toxic atmosphere is the densest in our solar system.

The planet, called 55 Cancri e or Janssen, is about 8.8 times more massive than Earth, with a diameter about twice that of our planet. It orbits its star at one-25th the distance between our solar system’s innermost planet Mercury and the sun. As a result, its surface temperature is about 3,140 degrees Fahrenheit (1,725 degrees Celsius/2,000 degrees Kelvin).

“Indeed, this is one of the hottest-known rocky exoplanets,” said astrophysicist and study co-author Brice-Olivier Demory of the University of Bern’s Center for Space and Habitability in Switzerland, using the term for planets beyond our solar system. “There are likely better places for a vacation spot in our galaxy.”

The planet is probably tidally locked, meaning it perpetually has the same side facing its star, much like the moon does toward Earth. The planet is located in our Milky Way galaxy about 41 light-years from Earth, in the constellation Cancer. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). Four other planets, all gas giants, are known to orbit its host star.

That star is gravitationally bound to another star in a binary system. The other one is a red dwarf, the smallest kind of ordinary star. The distance between these companions is 1,000 times the distance between Earth and the sun, and light takes six days to get from one to the other.

After all their searching, the rocky exoplanet for which scientists finally found evidence of an atmosphere turned out to be one that probably should not even have one. Being so close to its star, any atmosphere should be stripped away by stellar irradiation and winds. But gases dissolved in the vast lava ocean thought to cover the planet may keep bubbling up to replenish the atmosphere, Hu said.

“The planet cannot be habitable,” Hu said, because it is too hot to have liquid water, considered a prerequisite for life.

All of the previous exoplanets found to have atmospheres were gaseous planets, not rocky ones. As Webb pushes the frontiers of exoplanet exploration, the discovery of a rocky one with an atmosphere represents progress.

On Earth, the atmosphere warms the planet, contains the oxygen people breathe, protects against solar radiation and creates the pressure needed for liquid water to remain on the planet’s surface.

“On Earth, atmosphere is key for life,” Demory said. “This result on 55 Cnc e entertains the hope that Webb could conduct similar investigations on planets that are much cooler than 55 Cnc e, which could support liquid water at their surface. But we are not there yet.”