[youtube https://www.youtube.com/watch?v=4qyVNqeJ6wQ&w=800&h=450]The 1st-ever Mars livestream is scheduled to begin at noon ET (16 UTC, 18 CEST) today and last for one hour.

Wow! A Mars livestream?!

What next? The European Space Agency (ESA) said today (June 2, 2023) that it intends to broadcast a livestream – the first ever – from the red planet Mars. The livestream will last for one hour, as live images stream down directly from Mars roughly every 50 seconds. The livestream is scheduled to begin today at noon ET (16 UTC, 18 CEST). Watch in the viewer above.

And get live updates via @esaoperations on Twitter and with the hashtag #MarsLIVE.

On Friday, join us for one hour of the first-ever #MarsLIVE stream??https://t.co/0pnQvr6teY

To celebrate the 20th birthday of #MarsExpress, this will be the closest you can get to a live view from the Red Planet. Find out more?? https://t.co/jYz6k9ym6u pic.twitter.com/Wgs9a41g8c

— ESA Operations (@esaoperations) May 31, 2023

Will it work?

The images will come from the Visual Monitoring Camera on board ESA’s Mars Express orbiter. James Godfrey, Spacecraft Operations Manager at ESA’s mission control center in Darmstadt, Germany, said:

This is an old camera, originally planned for engineering purposes, at a distance of almost three million kilometers [2 million miles] from Earth – this hasn’t been tried before and to be honest, we’re not 100% certain it’ll work …

But I’m pretty optimistic. Normally, we see images from Mars and know that they were taken days before. I’m excited to see Mars as it is now – as close to a Martian ‘now’ as we can possibly get!

Mars Express 20th birthday

ESA wrote at its YouTube page:

On Friday, to celebrate the 20th birthday of ESA’s Mars Express, you’ll have the chance to get as close as it’s currently possible to get to a live view from Mars. Tune in to be among the first to see new pictures roughly every 50 seconds as they’re beamed down directly from the Visual Monitoring Camera on board ESA’s long-lived and still highly productive Martian orbiter.

Bottom line: The European Space Agency hopes to broadcast the 1st-ever Mars livestream today (June 2, 2023). Tune in at EarthSky.

Among exoplanets in our galaxy, super-Earths and mini-Neptunes are two of the most common types. Even though neither exists in our own solar system, astronomers have discovered many in other solar systems. Now, researchers at the University of Liège in Belgium say they have found a pair of these worlds in another solar system 150 light-years away. What makes this system extra interesting, however, is that these two planets are in a synchronous dance around their red dwarf star. The astronomers made the discovery using NASA’s Transiting Exoplanet Survey Satellite (TESS) and ground-based telescopes.

The researchers first published their peer-reviewed findings in Astronomy and Astrophysics on April 12, 2023. The University of Liège announced the discovery on May 25, 2023.

A collaborative discovery

Researchers in Europe and the U.S. collaborated to make the discovery, using data from both TESS and ground-based telescopes. Astrophysicist Francisco J. Pozuelos, the lead author, explained:

TESS is conducting an all-sky survey using the transit method, that is, monitoring the stellar brightness of thousands of stars in the search for a slight dimming, which could be caused by a planet passing between the star and the observer. However, despite its power to detect new worlds, the TESS mission needs support from ground-based telescopes to confirm the planetary nature of the detected signals.

TESS is designed specifically to search for exoplanets, planets orbiting other stars. This includes planets like super-Earths and mini-Neptunes, as well as Earth-sized rocky worlds.

A super-Earth and mini-Neptune

The two planets – TOI-2096 b and TOI-2096 c – are both larger than Earth. TOI-2096 b isn’t much bigger though, with a radius only 1.2 times that of Earth. This makes it a super-Earth, a rocky world larger than our own planet, but smaller than Neptune.

TOI-2096 c, on the other hand, is 1.9 times Earth’s radius. The researchers say that this likely makes it a mini-Neptune. It may have a small rocky and icy core, but it would be enveloped in a deep, thick atmosphere rich in either hydrogen or water. That means it would be similar to the ice giants in our solar system, Uranus and Neptune, but smaller. But these exoplanets also offer a unique look at both super-Earths and mini-Neptunes and how they may have formed. Co-author Mathilde Timmermans said:

These planets are of crucial importance given their sizes. The formation of super-Earths and mini-Neptunes remains a mystery today. Several formation models try to explain it, but none fits the observations perfectly. TOI-2096 is the only system found to date with a super-Earth and a mini-Neptune precisely at the sizes where the models contradict each other. In other words, TOI-2096 may be the system we’ve been looking for to understand how these planetary systems have formed.

Two worlds in a synchronized dance

A super-Earth and mini-Neptune in the same system is interesting on its own. But there’s more. The orbits of the two planets are synchronized with each other.

In the same time that the outer planet completes one orbit, the inner planet completes two. You could say that the planets are in a kind of cosmic dance with each other. Timmermans explained:

Making an exhaustive analysis of the data, we found that the two planets were in resonant orbits: for each orbit of the outer planet, the inner planet orbits the star twice.

Their periods are, therefore, very close to being a multiple of each other, with about 3.12 days for planet b and about 6.38 days for planet c. This is a very particular configuration, and it causes a strong gravitational interaction between the planets. This interaction delays or accelerates the passage of the planets in front of their star and could lead to the measurement of the planetary masses using larger telescopes in the near future.

Super-Earth and mini-Neptune observations with Webb

Luckily, these two planets are well-suited for observations with NASA’s Webb Space Telescope. Pozuelos said:

Furthermore, these planets are among the best in their category to study their possible atmospheres. Thanks to the relative sizes of the planets with respect to the host star, as well as the brightness of the star, we find that this system is one of the best candidates for a detailed study of their atmosphere with the JWST space telescope. We hope to be able to do this quickly by coordinating with other universities and research centers. These studies will help confirm the presence of an atmosphere, extensive or not, around planets b and c, thus giving us clues as to their formation mechanism.

Bottom line: Astronomers say they’ve discovered a super-Earth and mini-Neptune exoplanet system where the orbits of the two worlds are synchronized in a cosmic dance.

Source: A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096

Via University of Liège

When to watch: Venus came into view after sunset in December 2022 and has been visible in the evening sky throughout the first half of 2023. Greatest elongation – when Venus will be farthest from the sunset – happens on June 4, 2023. Afterwards, Venus will quickly sink toward the sunset as it races toward its sweep between the Earth and sun around mid-August 2023.
Where to look: Look in the sunset direction while the sky is darkening. You can’t miss Venus as the dazzling evening “star.”
Greatest elongation is at 11 UTC on June 4. That’s a whole-Earth time … for all of us, Venus will still appear in our evening sky, in the west after sunset. At this elongation, the distance of Venus from the sun on the sky’s dome is 46 degrees.
Magnitude at greatest elongation: Venus shines at magnitude -4.4.
Through a telescope: Venus appears 49% illuminated, in a first quarter phase, 23.56 arcseconds across.
Note: As the sun’s 2nd planet, Venus is bound by an invisible tether to the sun in our sky. It’s always east before sunrise, or west after sunset (never overhead at midnight). Venus is the brightest planet visible from Earth and shines brilliantly throughout every morning or evening apparition. Greatest elongation happens when Venus is farthest from the sun on the sky’s dome.

For precise sun and Venus rising times at your location:

Old Farmer’s Almanac (U.S. and Canada)

timeanddate.com (worldwide)

Stellarium (free online planetarium program)

Venus after sunset in 2023 Northern Hemisphere

Venus after sunset in 2023 Southern Hemisphere

A comparison of elongations

Not all of Venus’s greatest elongations are created equal. That’s because the farthest from the sun that Venus can ever appear on the sky’s dome is about 47.3 degrees. On the other hand, the least distance is around 45.4 degrees.

Elongations are also higher or lower depending on the time of year they occur and your location on Earth.

Venus events from late 2022 into 2024

October 22, 2022: Superior conjunction (passes behind sun from Earth)
June 4, 2023: Greatest elongation (evening)
August 13, 2023: Inferior conjunction (races between Earth and sun)
October 23, 2023: Greatest elongation (morning)
June 4, 2024: Superior conjunction (passes behind sun from Earth)

Bottom line: At greatest eastern elongation on June 4, 2023, Venus is as far from the sunset as it will be for this evening apparition.

Mars and the Beehive

On the evenings of June 1 and 2, 2023, you can spot Mars as it passes through a background star cluster known as the Beehive in Cancer the Crab. In fact, Mars appears as a big, bright ruby surrounded by tiny diamonds of distant stars.

First, to find Mars, look for brilliant Venus in the west, which at magnitude -4.3, wants to steal the show. You may also notice two bright stars strung out to one side of Venus. These are the twin stars in Gemini, Pollux and Castor. Above Venus and this duo is a bright, reddish light … that’s Mars. And if you’re in a dark-sky site or have binoculars, you can spot the smattering of stars beside the red planet.

A closer look at the Beehive star cluster

You’ll want binoculars to get a good look at just some of the 1,000 stars in the Beehive. While you can spot the cluster with your eyes alone, they will appear as a misty patch. However, with optical aid, the true nature of this star cluster comes alive.

The stars in this cluster lie about 577 light-years distant. So when you gaze at the Beehive, think about how many planets might reside among these 1,000 stars. We already know of at least two (Pr0201b and Pr0211b).

Do you have a photo to share? Submit it at EarthSky Community Photos. We sure enjoy seeing them.

Bottom line: Spot Mars and the Beehive star cluster together on June 1 and 2, 2023. You’ll want binoculars to get a good view of the starry cluster making a sparkling background for the red planet.

Want to see more night sky events? Visit EarthSky’s night sky guide

Our charts are mostly set for the northern half of Earth. To see a precise view from your location, try Stellarium Online.

We think of habitable exoplanets as residing in a star’s habitable zone. That makes sense, right? It’s the region around a star where liquid water might exist, perhaps on a rocky planet similar to Earth. But there might be another important zone – related to habitability – that astronomers have mostly overlooked: the soot zone. Researchers at the University of Michigan said on May 25, 2023, that astronomers could expand the search for habitable exoplanets by taking the soot zone into account.

This zone in a protoplanetary disk – or planet-forming – is the space between the star and the soot line.

The researchers published their peer-reviewed findings in The Astrophysical Journal Letters on May 25, 2023.

Expanding the search for habitable exoplanets

The habitable zone is typically the first place that astronomers look for potentially habitable planets. That is based on what we know about our own solar system, and how the Earth has been able to hold onto its oceans and other water. Earth resides within the sun’s habitable zone while Mars and Venus are near the outskirts.

But astronomer Ted Bergin, who led the study, and his colleagues want to also consider the soot zone. The soot zone is the space between the star and the soot line. The soot line, specifically, is the outer boundary near a star where solid carbon molecules are destroyed and sublimate into gas. They become volatile carbon compounds instead of remaining as solid ones. Volatiles are chemical elements and compounds that can vaporize easily.

Planets in this zone may be rich in volatile carbon compounds, and those compounds could be quite different than anything on our own planet. What would such planets be like? Could they be habitable?

Bergin said:

It adds a new dimension in our search for habitability. It may be a negative dimension or it may be a positive dimension. It’s exciting because it leads to all kinds of endless possibilities.

Water-poor and carbon-poor Earth

But these planets may also be water-poor. That sounds bad for habitability, but Earth is water-poor as well. Surprisingly, our planet contains only 0.1% water by mass.

Because of such little water content, scientists have long thought that Earth formed inside the frost line, or water-ice line, which is farther out from the sun. Bodies beyond that line tend to have a greater amount of water, percentage-wise, like the icy moons with subsurface oceans.

We also think of Earth as carbon-rich, but, as with water, it’s carbon-poor. Scientists say that while our planet was forming, it received only about one carbon atom per 100 that were available in the protoplanetary disk. The soot line may be responsible for this. If the building blocks of the young Earth formed inside the soot line, closer to the sun, then the volatile carbon compounds would have been turned into gas. That would limit the amount of solid carbon available for the forming planet.

Planets between the soot line and frost line

The study also focuses on exoplanets born between the soot line and frost line. There aren’t any in our own solar system, but astronomers have discovered many in other solar systems. They are typically super-Earth and mini-Neptune worlds. Both are larger in mass than Earth, but smaller in mass than Neptune. They are also the most common type of exoplanets found so far. Bergin said:

These are either big rocks or small gas giants; that’s the most common type of planetary system. So maybe, within all those other solar systems out in the Milky Way galaxy, there exists a population of bodies that we haven’t recognized before that have much more carbon in their interiors. What are the consequences of that? What this means for habitability should be explored.

Hazy methane atmospheres

The researchers modeled what these planets would be like, and found that they would likely have very hazy atmospheres. In the study, these planets, in the soot zone, are silicate-rich, with between 0.1% and 1% carbon by mass. They also have variable amounts of water. The models suggested that these worlds would outgass volatile carbon compounds and develop methane-rich atmospheres. The methane atmosphere would produce hazes, due to interaction with photons from the planets’ host stars. This is similar to how the hydrocarbon haze in Titan’s atmosphere is produced. Bergin explained:

Planets that are born within this region, which exists in every planet-forming disk system, will release more volatile carbon from their mantles. This could readily lead to the natural production of hazes. Such hazes have been observed in the atmospheres of exoplanets and have the potential to change the calculus for what we consider habitable worlds.

So, are those exoplanets habitable?

This could mean that a planet like this is potentially habitable, since the haze is evidence for a possibly carbon-rich mantle on the planet. And life – as we know it on Earth – is based on carbon. But with potentially more carbon and methane-rich atmospheres, these worlds would be quite unlike Earth in many ways.

Bergin added:

If this is true, then there could be a common class of haze planets with abundant volatile carbon, and what that means for habitability needs to be explored. But then there’s the other aspect: What if you have an Earth-sized world, where you have more carbon than Earth has? What does that mean for habitability, for life? We don’t know, and that’s exciting.

NASA’s James Webb Space Telescope (JWST) will be able to look at some of these worlds, as the paper notes:

Such hazes, and the methane that drives their formation, are detectable via JWST transit spectroscopy, as demonstrated here, especially around stars lower in mass (and therefore size) than the sun.

That, too, will be exciting.

Bottom line: Astronomers say that habitable exoplanets could form in the soot zone around young stars. They could be rich in volatile carbon compounds, different from Earth.

Source: Exoplanet Volatile Carbon Content as a Natural Pathway for Haze Formation

Via University of Michigan

We know that Mars had rivers and lakes in the distant past. But what about oceans? There is indeed tentative evidence for an ancient ocean in the northern hemisphere. However, scientists have been debating that evidence for decades. But now, researchers in China and the U.S. say they have found new clues in marine sedimentary rocks in Utopia Planitia that may prove the existence of that ocean. China’s Zhurong rover discovered the sedimentary formations. The researchers announced the tantalizing findings in Science China Press on May 21, 2023.

Professor Long Xiao from the School of Earth Sciences at China University of Geosciences led the research team. The team published its accepted peer-reviewed paper in National Science Review on May 18, 2023. The paper, still undergoing final editing, is available as a PDF.

New evidence for ancient ocean on Mars

China’s Zhurong rover has been exploring its landing site on the southern edge of Utopia Planitia in the northern hemisphere of Mars. This is within the northern lowlands that some scientists say was likely once an ocean floor. The rover’s newest findings now bolster that possibility. The rover has been studying the rocks in the area with its multispectral camera (MSCam), and the science team says that Zhurong has found marine sedimentary rocks. While most other data supporting the ocean hypothesis has come from orbiting spacecraft, this new data is in situ (on site).

It is the Vasitas Borealis Formation (VBF) that the mission scientists interpret to be marine sedimentary rocks. As the paper explains:

Decades of research using remotely-sensed data have extracted evidence for the presence of an ocean in the northern lowlands of Mars in the Hesperian, but these claims have remained controversial due to the lack of in situ analysis of the associated geologic unit, the Vastitas Borealis Formation (VBF). The Tianwen-1/Zhurong rover was targeted to land within the VBF near its southern margin and has traversed almost 1.2 miles (2 km) southward toward the interpreted shoreline. We report here on the first in situ analysis of the VBF that reveals sedimentary structures and features in surface rocks that suggest that the VBF was deposited in a marine environment, providing direct support for the existence of an ancient (Hesperian) ocean on Mars.

Multispectral images provide clues

Zhurong has been gradually moving south toward what is thought to be an ancient coastline. The rover has taken 106 panoramic images so far during its travels. Mission scientists have been studying the multispectral images for clues about the rocks’ composition and origin. They found bedding structures that are different from the usual volcanic rock deposits on Mars.

In addition, they were different from rock formations created by blowing sand.

A shallow sea environment

Indeed, the images revealed bidirectional flow, a sign of possible low-energy tidal currents. They are similar to formations created in shallow marine environments on Earth. The mission team named this region the Zhurong Member. The rocks feature small-scale cross-bedding, lens-shaped flaser bedding and small channel structures.

The paper says:

Bidirectional current orientations are characteristically formed by regular opposite directions of tidal currents in terrestrial shallow marine environments, and uncommonly in fluvial environments. Although aeolian deposits on Mars also contain some small-scale cross-laminations, the lack of larger structures indicative of aeolian environments supports the interpretation that these are of shallow marine origin.

The images also showed that the layers in the cross-bedding overlap and tilt in two opposite directions. The thickness of the strata, as well as the size of sand grains, also differs. This is evidence for a bidirectional water flow pattern. On Earth, this is common in littoral-shallow sea environments.

Ancient shorelines of an ocean on Mars and a wild river

Last year, researchers at Penn State and Caltech said they discovered definitive traces of an old shoreline in Mars’ northern hemisphere.

And just last week, scientists announced that the Perseverance rover has found evidence for a rollicking river. It was the deepest and fastest-flowing river yet observed – now all dried up of course – by any rover or lander.

The new findings from the Zhurong rover would seem to support this, adding another crucial piece to the puzzle. That ocean would have been vast, covering most of the northern hemisphere of Mars. The next question, of course, is whether it supported any kind of life. It will be interesting to see what else Zhurong finds in its travels, as well as any future missions to this now-dry ocean wonderland.

Bottom line: Scientists in China say that the Zhurong rover has found new evidence for an ancient ocean on Mars, sedimentary rocks formed in a shallow marine environment. The ocean would have covered hundreds of thousands of square kilometers. They estimate the ancient Martian shoreline to be 3.5 billion years old.

Source: Evidence for marine sedimentary rocks in Utopia Planitia: zhurong rover observations

Via Science China Press/ Eurekalert!