Space News & Blog Articles

Roughly two years and six months from now, as part of NASA’s Artemis III mission, astronauts will set foot on the lunar surface for the first time in over fifty years. Beyond this mission, NASA will deploy the elements of the Lunar Gateway, the Artemis Base Camp, and other infrastructure that will allow for a “sustained program of lunar exploration and development.” They will be joined by the European Space Agency (ESA), the China National Space Agency (CNSA), and Roscosmos, the latter two collaborating to build the International Lunar Research Station (ILRS).

Anticipating this process of lunar development (and looking to facilitate it), the Defense Advanced Research Projects Agency (DARPA) launched the 10-year Lunar Architecture (LunA-10) Capability Study in August last year. In recent news, the agency announced that it selected Northrop Grumman to develop a moon-based railroad network. This envisioned network could transport humans, supplies, and resources for space agencies and commercial ventures, facilitating exploration, scientific research, and the creation of a lunar economy.

According to DARPA, the seven-month LunA-10 study aims to establish “an analytical framework that defines new opportunities for rapid scientific and commercial activity on and around the Moon.” It also aims to foster the development of foundational technology to optimize lunar infrastructure, allowing space agencies to move away from individual efforts within isolated, self-sufficient systems and towards shareable, scalable, resource-driven systems that can operate together. In keeping with NASA’s long-term objectives, this work will complement the administration’s “Moon to Mars” objectives.

Artist rendition of construction of the Moon. Credit: NASA.

In layman’s terms, the plan is to develop the technologies that will allow space agencies and companies to access each others’ resources, facilities, and information to promote further growth opportunities. Several key sectors are identified in the solicitation that must be developed into services to sustain a long-term presence on the Moon based on an independent market analysis of the future lunar economy. They include construction, mining, transit, energy, agriculture, and research (e.g., medicine, robotics, and life sustainment) that will have applications for space exploration and life on Earth.

For nearly three decades now, it’s been clear that the expansion of the Universe is speeding up. Some unknown quantity, dramatically dubbed ‘dark energy’, is pushing the Universe apart. But the rate at which the Universe’s expansion is increasing – called the Hubble Constant – hasn’t yet been nailed down to a single number.

Not for lack of trying.

In fact, there are multiple ways of measuring it. The problem is that these methods don’t agree with each other. They each give different numbers, which is a confounding – and exciting – puzzle. It means there may be new physics to uncover, if we look carefully.

This mystery is known as the Hubble tension, and it’s only becoming more intractable as measurement techniques become more precise. So astronomers are on the hunt for new and better ways to measure the expansion of the Universe.

In a new paper this week, three Swiss scientists describe a method for significantly improving one measurement technique.

Fortunately, the real-world search for signs of extraterrestrial civilizations doesn’t have to deal with an alien armada like the one that’s on its way to Earth in “3 Body Problem,” the Netflix streaming series based on Chinese sci-fi author Cixin Liu’s award-winning novels. But the trajectory of the search can have almost as many twists and turns as a curvature-drive trip from the fictional San-Ti star system.

Take the Breakthrough Initiatives, for example: Back in 2016, the effort’s billionaire founder, Yuri Milner, teamed up with physicist Stephen Hawking to announce a $100 million project to send a swarm of nanoprobes through the Alpha Centauri star system, powered by light sails. The concept, dubbed Breakthrough Starshot, was similar to the space-sail swarm envisioned in Liu’s books — but with the propulsion provided by powerful lasers rather than nuclear bombs.

Today, the Breakthrough Initiatives is focusing on projects closer to home. In addition to the millions of dollars it’s spending to support the search for radio or optical signals from distant planetary systems, it’s working with partners on a miniaturized space telescope to identify planets around Alpha Centauri, a radio telescope that could someday be built on the far side of the moon, and a low-cost mission to look for traces of life within the clouds of Venus.

Pete Worden is the executive director of the Breakthrough Initiatives. (Credit: Breakthrough Initiatives)

Breakthrough Starshot, however, is on hold. “This looks to be quite feasible. However, it seems to be something that is still pretty, pretty expensive, and probably wouldn’t be feasible until later in the century,” says Pete Worden, executive director of the Breakthrough Initiatives. “So, we’ve put that on hold for a period of time to try to look at, are there near-term applications of this technology, which there may be.”

The JWST is enormously powerful. One of the reasons it was launched is to examine exoplanet atmospheres to determine their chemistry, something only a powerful telescope can do. But even the JWST needs time to wield that power effectively, especially when it comes to one of exoplanet science’s most important targets: rocky worlds orbiting red dwarfs.

Red dwarfs are the most common type of star in the Milky Way. Observations show that red dwarfs host many rocky planets in their habitable zones. There are unanswered questions about red dwarf habitable zones and whether the rocky planets in these zones are truly habitable because of well-documented red dwarf flaring. Astronomers want to examine these planets’ atmospheres and look for biosignatures and other atmospheric information.

New research suggests that it could take the capable JWST hundreds of hours of observing time to detect these atmospheres to a greater degree of certainty. The new research is “Do Temperate Rocky Planets Around M Dwarfs Have an Atmosphere?” The sole author is Rene Doyon from the Physics Department at the University of Montreal, Canada. The paper hasn’t been peer-reviewed yet.

Doyon points out that even though one of the JWST’s main goals is to probe exoplanet atmospheres, it’s only done that for a small handful of planets: Trappist-1d, e, f, g, LHS1140b, and the mini-Neptune K2-18b.

These results have shown that the JWST has the power to probe exoplanet atmospheres. But the effort has also shown how stellar activity poses an obstacle to even more success. The JWST examines exoplanet atmospheres by watching as the planet transits its star. The telescope dissects the light from the star as it passes through the exoplanet’s atmosphere, looking for the light signatures of different molecules.

Can Europa’s massive, interior ocean contain the building blocks of life, and even support life as we know it? This question is at the forefront of astrobiology discussions as scientists continue to debate the possibility for habitability on Jupiter’s icy moon. However, a recent study presented at the 55th Lunar and Planetary Science Conference (LPSC) might put a damper in hopes for finding life as a team of researchers investigate how Europa’s seafloor could be lacking in geologic activity, decreasing the likelihood of necessary minerals and nutrients from being recycled that could serve as a catalyst for life.

Here, Universe Today speaks with Henry Dawson, who is a PhD student in the Department of Earth, Environmental, and Planetary Sciences at Washington University in St. Louis and lead author of the study, about his motivation behind the study, significant results, follow-up studies, and whether Dawson believes there’s life on Europa. So, what was the motivation behind this study?

Dawson tells Universe Today, “A large portion of the community has been looking at the habitability potential of the seafloor, and looking at processes that might occur at seafloor hydrothermal vents, or at water–rock interaction chemistry. However, it was never established that there would actually be any fresh rock exposed at the seafloor, or if the tectonic processes that drive hydrothermal vents would be present. The silicate interior of Europa is a similar size to that of Earth’s Moon, which is largely geologically dead on the surface.”

Artist’s cutaway illustration of Europa and its potential geologic activity. (Credit: NASA/JPL-Caltech/Michael Carroll)

For the study, Dawson and his colleagues examined the likelihood for geologic activity occurring on Europa’s seafloor through analyzing data on Europa’s geophysical characteristics and comparing them with known geologic parameters and processes, including the strength of potential fault lines and fractures within Europa’s rocky interior, how the strength of this rock changes with depth, and how the rock could react to ongoing stresses, commonly known as convection. Using this, they conducted a series of calculations to ascertain whether the seafloor crust could drive geologic activity. Therefore, what were the most significant results from this study?

You can tell a lot about a planetary body just by looking at its surface, especially if it has craters. Take Europa, for example. It has a fairly young surface—somewhere between 50 and 100 million years old. That’s practically “new” when you compare it to the age of the Solar System. And, Europa’s icy crust is pretty darned smooth, with only a few craters to change the topography.

Planetary scientists already know that Europa’s icy surface is a thin shell over a large interior ocean of salty water. How thin? To find out, a team of researchers led by Brandon Johnson and Shigeru Wakita at Purdue University studied images of large craters on Europa. They used what they saw, coupled with a variety of physical characteristics, to create computer models of that shell. “Previous estimates showed a very thin ice layer over a thick ocean,” said Wakita. “But our research showed that there needs to be a thick layer—so thick that convection in the ice, which has previously been debated, is likely.”

The thickness of that shell may well influence whether or not life exists at Europa. Its existence is a topic of intense interest since Europa could provide a reasonably habitable ecosystem for life. It has water, warmth, and organic materials for life to eat. That makes the search for life at Europa quite important. So, what do craters have to do with all this?

Impact cratering performs a lot of gardening in the Solar System, according to Johnson. He is the first author on a recently published paper discussing these features on Europa. “Craters are found on almost every solid body we’ve ever seen. They are a major driver of change in planetary bodies,” he said.

Four featured craters among many on the Moon: the triplet of Theophilus, Cyrillus and Catharina and Maurolycus. Many more craters can be seen across the lunar surface. Credit: Virtual Moon Atlas / Christian LeGrande, Patrick Chevalley

That stars can eat planets is axiomatic. If a small enough planet gets too close to a large enough star, the planet loses. Its fate is sealed.

New research examines how many stars eat planets. Their conclusion? One in twelve stars has consumed at least one planet.

The evidence comes from co-natal stars, which aren’t necessarily binary stars. Since these stars form from the same molecular cloud, they should have the same ingredients. Their metallicity should be nearly identical.

But for about one in twelve stars, there are clear differences.

The new research is titled “At least one in a dozen stars shows evidence of planetary ingestion,” and it’s published in the journal Nature. The lead author is Fan Liu, an ASTRO 3D Research Fellow in the School of Physics and Astronomy at Monash University, Melbourne, Australia.

Communication between spacecraft relies upon line of site technology, if anything is in the way, communication isn’t possible. Exploration of the far side of the Moon is a great example where future explorers would be unable to communicate directly with Earth.  The only way around this is to use relay satellites and the Chinese Space Agency is on the case. The first Queqiao-1 was able to co-ordinate communications with Chang’e-4 landers and now they are sending Queqiao-2 to support the Change’e-6 mission. 

If you have ever gazed upon the Moon you might have noticed that it always has the same hemisphere facing the Earth. This phenomenon is known as captured or synchronous rotation. It may look like the Moon isn’t rotating but in reality the time it takes to spin once on its axis is the same as the time it takes to complete one orbit around the Earth, keeping one hemisphere constantly facing us. Explorers on the near side of the Moon have no trouble communicating with transmissions taking just over one second to reach home. Explore the far side of the Moon and you have a problem. 

To overcome the problem China have launched a 1.2 ton communication satellite known as Queqiao-2. It’s name originates from the mythological bridge made from magpies. In the Chinese tale, the magpies formed a bridge across the Milky Way to allow the lovers Vega and Altair to be together for one night once a year. Two miniature satellites were also launched Tiandu-1 and Tiandu-2 from the island of Hainan.

On arrival it will orbit the Moon and provide a relay for the Chang’e-6 lander which is slated to launch in May.  It will join satellites from United States, India and Japan to support the exploration of the far side of the Moon. Chang’e-6 will collected samples from an ancient basin. Not only will it serve the communications for Change-6, it will transfer communications for Chang’e-7 and ‘8. Both craft are to be launched in the years ahead 2026 and 2028 respectively. 

The orbit of Queqiao-2 will take it almost over the south pole in an elliptical orbit. It will reach an altitude of 8,600 km so that communication can be achieved for a little over eight hours. At its closest, it will sweep over the lunar surface at an altitude of 300 km.

Totality and the April 8th total solar eclipse offers a rare chance to study the Sun.

We’re less than three weeks out now, until the April 8th total solar eclipse crosses North America. And while over 31 million residents live in the path of totality, many more will make the journey to briefly stand in the shadow of the Moon. Several scientific projects are also underway to take advantage of the event.

The eclipse traverses Mexico, the United States from Texas to Maine, and the Canadian Maritime provinces before heading out over the Atlantic. Maximum totality for this eclipse in 4 minutes and 27 seconds, longer than the 2017 total solar eclipse. This is the only total solar eclipse worldwide for 2024, and the final total solar eclipse for a generation for the contiguous United States until 2044.

Eclipses have always offered astronomers a chance to carry out rare observations. The element helium (named after ‘Helios’ the Greek god of the Sun) was discovered in the solar chromosphere during the August 18th, 1868 total solar eclipse. Astronomers swept the sky near the eclipsed Sun in July 29th, 1878, looking for the hypothetical planet Vulcan. World War I thwarted astronomer’s plans to test Einstein’s Theory of General Relativity during the August 21st, 1914 eclipse. This had to wait until Arthur Eddington led an expedition to Principe in 1919. Eddington vindicated Einstein with measurements of the deflection of stars observed near the Sun during totality.

Stranger experiments continued right up into the 20th century. One of the more bizarre eclipse experiments was hunting for the elusive ‘Allais Effect,’ looking for the deflection of a pendulum during totality. Alas, Maurice Allais’ findings alluding to this fringe idea have never been replicated. Maybe LIGO Livingston just outside the path of totality on 2024 could take up the challenge?

After over 70 successful flights, a broken rotor ended the remarkable and groundbreaking Ingenuity helicopter mission on Mars. Now, NASA is considering how a larger, more capable helicopter could be an airborne geologist on the Red Planet. For the past several years scientists and engineers have been working on the concept, proposing a six-rotor hexacopter that would be about the size of the Perseverance rover.

Called the Mars Science Helicopter (MSH), it would not only serve as an aerial scout for a future rover, but more importantly, it could also carry up to 5 kg (11 lbs) of science instruments aloft in the thin Martian atmosphere and land in terrain that a rover can’t reach.

A new paper presented at the March 2024 Lunar and Planetary Science Conference outlines the geology work that such a helicopter could accomplish.

The paper, “Unraveling the Origin and Petrology of the Martian Crust with a Helicopter,” notes there are several outstanding questions about the makeup and history of Mars’ surface, especially with recent discoveries of unexpected dichotomies in the composition of basaltic rocks. In observations from the Mars rovers and orbital spacecraft, some regions appear to have been influenced by water while some have not.

“Up to last decade, we thought that magmatic rocks were only basaltic on Mars,” said Valerie Payré from the University of Iowa, the paper’s lead author. “But with recent rover and orbital measurements, we observed that there is a wide diversity of magmatic rocks similar to what we see on Earth.”

The US Government budget announcement in March left NASA with two billion dollars less than it asked for. The weeks that followed have left NASA with some difficult decisions forcing cuts across the agency. There will be a number of cuts across the agency but one recent decision came as quite a shock to the scientific community. NASA have just announced they are no longer going to support the Chandra X-Ray Observatory which has been operational since 1999 and made countless discoveries. 

Chandra was launched back in 1999 and has become pivotal in the world of X-ray astronomy. X-ray observatories like Chandra have to be placed in orbit because the atmosphere blocks the X-ray radiation from reaching Earth. Like other high energy telescopes, the mirrors of Chandra have to be placed at shallow angles to the incoming high energy beams. If they were placed perpendicular the X-rays would zip straight through. Instead, multiple mirrors are placed at shallow angles to gently guide the radiation to a focus. 

Since its launch it has captured high resolution X-ray images of black holes, supernova remnants, pulsars and galaxy clusters. The X-rays allow us to look deep inside these extreme objects to show detail which is usually impossible to see. It’s first image was the supernova remnant Cassiopeia A, it revealed forward and reverse shockwaves and ejecta from the pre-supernova state.

NASAs budget statement was released on 11 March where it revealed its plans for 2025 and beyond. In the statement it read “The reduction to Chandra will start orderly mission drawdown to minimal operations.” Thankfully NASA has already identified a plan of action should Chandra experience mission-ending failure. The loss of funding and the decision to scale back Chandra activity has meant these procedures swing into action. They include the closedown of flight operations, finalisation of data and source catalog, documentation of calibration and other critical products and much more. 

The budget document went on with the rationale for the decision “The Chandra spacecraft has been degrading over its mission lifetime to the extent that several systems require active management to keep temperatures within acceptable ranges for spacecraft operations. This makes scheduling and the post processing of data more complex, increasing mission management costs beyond what NASA can currently afford.”

The Moon is practically begging to be explored, and the momentum to do so is building. The Artemis Program’s effort to return astronauts to the Moon for the first time since the Apollo missions captures a lot of attention. But there are other efforts underway.

In 2023, the ESA put out a call for small lunar missions. The call was associated with their Terra Novae exploration program, which will advance the ESA’s exploration of the Solar System with robotic scouts and precursor missions. “Humankind will benefit from the new discoveries, ambitions, science, inspiration, and challenges,” the ESA explains on their Terra Novae website.

Terra Novae has several goals, one of which is to “Land multiple scientific payloads on the surface of the Moon, prospecting for the presence of water and other volatile materials that will both reveal its history and help prepare sustainable exploration by locally sourced space resources.”

In response to the ESA’s call, a team of European researchers have proposed the LunarLeaper. The LunarLeaper is a hopping robot that would visit a lunar skylight, a collapsed part of a lunar lava tube. The robot would give us our first look at the lunar subsurface and the lava tubes.

There are good reasons to explore these lava tubes. The lunar surface is exposed to solar and cosmic radiation without the benefit of a protective atmosphere or magnetosphere like Earth. Astronauts could shelter in these tubes inside habitat modules. Several meters of rock overhead would provide protection from radiation and from the Moon’s temperature swings. There could be laboratory modules and other modules as well. The tubes, if suitable, could shelter an entire base.

Nature often defies our simple explanations. Take comets and asteroids, for example. Comets are icy and have tails; asteroids are rocky and don’t have tails. But it might not be quite so simple, according to new research.

That nice, clean definition took a hit in 1996 when a pair of astronomers discovered that what was thought to be a main-belt comet was actually an asteroid. The object is named 7968 Elst–Pizarro after the two scientists. It displayed a comet-like dust tail at perihelion.

7968 Elst-Pizarro was classified as a main-belt comet (MBC) because it orbits within the main asteroid belt between Mars and Jupiter. It’s still called an MBC sometimes. However, its icy component that sublimates into a vapour trail likely comes from a small surface crater with volatiles in it rather than from a homogenous ice component. That’s why it’s called an active asteroid.

Active asteroids are unusual and rare objects. To understand them and their place in the Solar System’s history, scientists want to find more of them. That led to the creation of NASA’s Active Asteroids Project.

Now, the Active Asteroids Project has announced the discovery of 15 new active asteroids. These findings are in a new paper published in The Astronomical Journal. It’s titled “The Active Asteroids Citizen Science Program: Overview and First Results,” and the lead author is Colin Chandler from the Dept. of Astronomy & the DiRAC Institute at the University of Washington in Seattle. Among the co-authors are nine volunteer citizen scientists.

The Earth’s place in space is a fairly familiar one with it orbiting an average star. The star – our Sun – orbits the centre of our Galaxy the Milky Way. From here onwards, the story is less well known. The Milky Way is part of a large structure called the Laniakea Supercluster which is 250 million light years across! That really is a whacking great area of space and it contains at least 100,000 galaxies. There are larger superclusters though like the newly discovered Einasto Supercluster which measures an incredible 360 million light years across and is home to 26 quadrillion stars!

When I give public lectures, I always get a strange satisfaction out of telling the audience that galaxies don’t exist! I go on to explain that, like a city which is a collection of stuff, galaxies are collections of things bound together under the force of gravity. A typical galaxy is simply a collection of stars, nebulae, clusters, planets, comets and so on, take them away and a galaxy won’t exist! Superclusters are largely the same, just a collection of galaxies bound together (well, not completely) under the force of gravity. 

Superclusters like Laniakea and Einasto (which is 3 billion light years away) are among the largest structures in the Universe. The discovery of this latest supercluster has been named after Professor Jaan Einasto who was a pioneer in the field of superclusters and celebrated his 95th birthday on 23 February 2024. 

When it comes to visualising the sheer size of these structures imagine an average coin (I really don’t think it matters too much which coin you imagine) on a football pitch. This coin represents the Milky Way Galaxy and the length of the pitch would be the extremities of the supercluster! You might also imagine the Sun as a golf ball and the entire collective mass of the supercluster as Mount Everest in comparison!

The announcement came from a group of international astronomers from the Tartu Observatory who also surveyed 662 other superclusters. Their work (which was published in the Astrophysical Journal) also revealed some interesting dynamics inside superclusters for example, they found that the galaxies within a supercluster are receding from each other slower than the general expansion of the universe. This is due to the gravitational pull of the supercluster acting as a brake on the expansion. Whilst it is slowing the expansion of the area it is not slowing it enough to stop the galaxies from drifting apart given enough time. Superclusters should be considered temporary, changing phenomena.

There are plenty of craters on Mars, especially when compared to Earth. That is primarily thanks to the lack of weathering forces and strong plate tectonics that disrupt the formations of such impacts on our home planet. However, not all impact craters on Mars are directly caused by asteroid impacts. Many of them are caused by the ejecta from an asteroid impact falling back to the planet. One recent study showed how impactful this can be – it concludes that a single large impact crater on Mars created over two billion other smaller craters up to almost 2000 km away.

The study, released at the 55th annual Lunar and Planetary Science Conference in Texas, focuses on a crater called Corinto. It’s located in Elysium Planitia, only about 17 degrees north of the Red Planet’s equator. It’s a relatively young crater by Martian standards, with the scientists’ best estimate of its age being around 2.34 million years ago. It’s pretty massive for being that young, though, as the average time between impacts of its size is around 3 million years. As such, the scientists think it might be the most recent crater of its size on Mars.

That’s not why it’s interesting, though. It has an extensive “ray system”. That means that a significant amount of ejecta was cast out from the impact site and landed elsewhere on the planet, creating “rays” from the central impact point that can be seen on a map of the planet’s surface even today.

Corinto crater is about 14 km in diameter and 1 km deep. Its interior bowl is pock-marked with other, smaller craters that happened its impact. Indications suggest it was full of water ice when it was hit, as there appeared to be some degassing of the superheated ice after the impact. Calculations point to a relatively steep impact angle of about 30-45 degrees from straight on – and the impactor appeared to be coming from the north.

As a result, much of the ejecta impact field lies to the south, especially the southwest, of the crater. While some secondary ejecta craters are sitting to the north of the main one, it appears clear that the impactor’s angle was significant enough to push most ejecta to the south. 

We are all too familiar of the Moon’s effect on our planet. It’s relentless tug causes our tides but even Mars, which is always at least 55 million kilometres away, can have a subtle effect too. A study has revealed a 2.4 million year cycle in the geological records that show the gentle warming and cooling of our oceans. The records match the interactions between the orbits of Earth and Mars over the longest timescales. These are known as the ‘astronomical grand cycles’ but to date, not much evidence has been found. 

The rhythmical rising and falling of the oceans has been well documented. Even the Sun at an average distance of 150 million kilometres exerts enough of a pull to enhance the effect from the Moon, giving us the spring and neap tides. The Moon’s influence is easy to understand due to its proximity, the Sun’s too due to its enormous mass but Mars is a different story. After all, it’s about half the size of Earth and even at its closest is about 55 million kilometres away. 

As Earth and Mars orbit around the Sun, their interactions, or rather the gravitational pull from each upon each other are cyclical. These are the astronomical grand cycles and for Earth and Mars they cycle every 2.4 million years.

A paper recently published in Nature Communications reports upon the work of scientists from the University of Sydney and Sorbonne University in France. The team used geological records from the deep sea and to their surprise found a connection between the astronomical grand cycles, global warming patterns and deep ocean circulation. They found a 2.4 million year waxing and waning of deep ocean currents and that seemed to link to increased climate. 

A definite link emerged but it should be noted that ocean currents are not the only cause of global temperature changes. The current temperature increases have a much stronger link to the human emission of greenhouse gasses.  The paper was authored by Dr Adriana Dutkiewicz and Professor Dietmar Muller from the University of Sydney and Associate Professor Slah Boulila from the Sorbonne University. They reached their conclusion following analysis of the deep-sea sediment records acquired from over half a century of drilling data from hundreds of sites worldwide. The 2.4 million year cycle they found can only have been caused by the interactions between Earth and Mars. 

We, and all other complex life, require stability to evolve. Planetary conditions needed to be benign and long-lived for creatures like us and our multicellular brethren to appear and to persist. On Earth, chemical cycling provides much of the needed stability.

Chemical cycling between the land, atmosphere, lifeforms, and oceans is enormously complex and difficult to study. Typically, researchers try to isolate one cycle and study it. However, new research is examining Earth’s chemical cycling more holistically to try to understand how the planet has stayed in the ‘sweet spot’ for so long.

Earth has supported complex life for hundreds of millions of years, possibly for more than a billion years. This is extremely rare, as far as we can tell. The vast majority of the exoplanets we’ve discovered are not in their stars’ habitable zones. They have very little chance of hosting any life, let alone complex life.

It’s possible that some planets experience a period of stability for much shorter periods of time than Earth. This may describe Mars. It was warm and wet and could’ve hosted simple life, but the planet lost most of its atmosphere and became uninhabitable. Now it’s cold, dry, and dead.

Earth robustly cycles the chemical elements through different systems and has done so for billions of years. Now, about 4.5 billion years after its formation, life is abundant on our precious planet. Biogeochemical cycles like the carbon cycle, the nitrogen cycle, and the methane cycle have allowed the planet to sustain its habitability.

Universe Today has examined the importance of studying impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, and planetary atmospheres, and how these intriguing scientific disciplines can help scientists and the public better understand how we are pursuing life beyond Earth. Here, we will look inward and examine the role that planetary geophysics plays in helping scientists gain greater insight into our solar system and beyond, including the benefits and challenges, finding life beyond Earth, and how upcoming students can pursue studying planetary geophysics. So, what is planetary geophysics and why is it so important to study it?

“Planetary geophysics is the study of how planets and their contents behave and evolve over time,” Dr. Marshall Styczinski, who is an Affiliate Research Scientist at the Blue Marble Space Institute of Science, tells Universe Today. “It is essentially the study of What Lies Below, focusing on what we can’t see and how it relates to what we can see and measure. Most of the planets (including Earth!) are hidden from view—geophysics is how we know everything about the Earth below the deepest we have dug down!”

As its name implies, geophysics is the study of understanding the physics behind geological processes, both on Earth and other planetary bodies, with an emphasis on interior geologic processes. This is specifically useful for planetary bodies that are differentiated, meaning they have several interior layers resulting from heavier elements sinking to the center while the lighter elements remain closer to the surface. 

The planet Earth, for example, is separated into the crust, mantle, and core, with each having its own sub-layers, and understanding these interior processes help scientists piece together what the Earth was like billions of years ago and even make predictions regarding the planet’s environment in the far future. These interior processes drive the surface processes, including volcanism and plate tectonics, both of which are responsible for maintaining the Earth’s temperature and recycling materials, respectively. So, what are some of the benefits and challenges of studying planetary geophysics?

Dr. Styczinski tells Universe Today, “Geophysics gives us the tools to determine what exists beneath the visible surface of planetary bodies (planets, moons, asteroids, etc.). It’s our only way to learn about what we can’t see! Finding out what is inside a planet, and under what conditions, like how much pressure and heat for each layer, helps us build a history for the planet and know how it will continue to change over time.”

Quasars are the brightest objects in the Universe. The most powerful ones are thousands of times more luminous than entire galaxies. They’re the visible part of a supermassive black hole (SMBH) at the center of a galaxy. The intense light comes from gas drawn toward the black hole, emitting light across several wavelengths as it heats up.

But quasars are more than just bright ancient objects. They have something important to show us about the dark matter.

Large galaxies have supermassive black holes at their centers. Even those only casually familiar with space know that black holes can suck everything in, even light. But as black holes draw nearby gas towards themselves, the gas doesn’t all go into the hole, past the event horizon and into oblivion. Instead, much of the gas forms a rotating accretion disk around the black hole.

SMBHs aren’t always actively drawing material to them, an act known as ‘feeding.’ But when an SMBH is actively feeding, it’s called an active galactic nucleus (AGN.) When the material in the disk rotates, it heats up. As it heats, it emits different wavelengths of electromagnetic radiation. It can also emit jets.

When astronomers first began to detect this light, they only knew they were seeing objects that emitted radio waves. The name quasar means quasi-stellar radio source. But as time went on astronomers learned more, and the term active galactic nucleus was adopted. The term quasar is still used, but they’re now a sub-class of AGN that are the most luminous AGN.

The exoplanet census now stands at 5,599 confirmed discoveries in 4,163 star systems, with another 10,157 candidates awaiting confirmation. So far, the vast majority of these have been detected using indirect methods, including Transit Photometry (74.4%) and Radial Velocity measurements (19.4%). Only nineteen (or 1.2%) were detected via Direct Imaging, a method where light reflected from an exoplanet’s atmosphere or surface is used to detect and characterize it. Thanks to the latest generation of high-contrast and high-angular resolution instruments, this is starting to change.

This includes the James Webb Space Telescope and its sophisticated mirrors and advanced infrared imaging suite. Using data obtained by Webb‘s Near-Infrared Camera (NIRCam), astronomers with the MIRI mid-INfrared Disk Survey (MINDS) survey recently studied a very young variable star (PDS 70) about 370 light-years away with two confirmed protoplanets. After examining the system and its extended debris disk, they found evidence of a third possible protoplanet orbiting the star. These observations could help advance our understanding of planetary systems that are still in the process of formation.

The MINDS survey is an international collaboration consisting of astronomers and physicists from the Max-Planck-Institute for Astronomy (MPIA), the Kapteyn Astronomical Institute, the Space Research Institute at the Austrian Academy of Sciences (OAW-IFW), the Max-Planck Institute for Extraterrestrial Physics (MPE), the Centro de Astrobiología (CAB), the Institute Nazionale di Astrofisica (INAF), the Dublin Institute for Advanced Studies (DIAS), the SRON Netherlands Institute for Space Research, and multiple universities. The paper that describes their findings will appear in the journal Astronomy & Astrophysics.

This spectacular image from the SPHERE instrument on ESO’s Very Large Telescope is the first clear image of a planet caught in the very act of formation around the dwarf star PDS 70. Credit: ESO/A. Müller et al.

PDS 70 has been the subject of interest in recent years due to its young age (5.3 to 5.5 million years) and the surrounding protoplanetary disk. Between 2018 and 2021, two protoplanets planets were confirmed within the gaps of this disk based on direct imaging data acquired by sophisticated ground-based telescopes. This included the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) and GRAVITY instruments on the ESO’s Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA).