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Astronomy

Mars had plenty of water in the past, but probably no life forms

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Mars has been in the news quite a lot these past few months, as I’m sure some of you may already know. This isn’t exactly a surprise seeing as how our neighboring planet is scheduled to receive human visitors at some point in the coming decades. Learning everything we can about Mars beforehand is certain to help scientists draw a better plan for the upcoming manned mission while also hyping up the general public so that they can contribute with what they can to what’s expected to be the next important milestone in space exploration.

Last month we were pleasantly surprised to learn that Mars still has a bit of water under its dry surface, however, according to a recent study it seems like this is just the remnant of an ocean that covered the planet billions of years ago. Astronomers have long since suspected that the Red Planet may have hosted large amounts of water in the past, but now thanks to NASA and the European Southern Observatory we have even more reasons to think that this was indeed the case. The research conducted using the Very Large Telescope found in Chile as well as the Hawaii-based Infrared Telescope Facility and  WM Keck Observatory suggests that Mars lost an ocean’s worth of water over the last 4 billion years.

“It implies that a substantial amount of water was available during the first billion years on Mars, raising the possibility that ancient Mars was habitable,” Geronimo Villanueva, a planetary scientist at NASA’s Goddard Space Flight Center, told Astrobiology Magazine.

To give us a better idea about just how much water was lost, the researchers claim that about 19% of Mars’ surface would have been covered by a mile deep ocean if all that water was still around today. These new findings could potentially indicate that Mars was once able to sustain life, especially since life as we know it seems to thrive in pretty much every place where there’s water. At least, that’s what the life forms found here on Earth would suggest. What’s true here may not be true everywhere though and some scientists are skeptical in regards to this theory. The skepticism comes from the fact that water may not have been widely available in liquid form on Mars because the planet was likely much colder than our own throughout its history.

The amount of water lost by Mars would have been enough to cover the entire planet in a 137 meter (499 feet) deep global ocean if we were to distribute it equally across its surface. Even though this seems like a pretty big amount, a global ocean on Earth would be several kilometers deep if we were to take all the water found here and spread it in a similar fashion. According to planetary scientist Robin Wordsworth from the Harvard School of Engineering and Applied Sciences, it’s very likely that Mars had very little water at any point during its history and the water it had was probably available as ice rather than liquid. This pretty much excludes the possibility of life, although more studies are needed before scientists can say for certain.

“Their [Villanueva’s] results are entirely consistent with a predominantly cold, icy scenario for early Mars,” said Wordsworth. “A global depth of 137 meters still implies a relatively dry planet, and doesn’t allow a deep northern ocean. The water could have mainly been in the form of ice rather than liquid.”

Although George has many hobbies, he likes nothing more than to play around with cameras and other photography equipment.

Astronomy

NASA’s flyby of Europa shows that “something” is moving under the ice

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Europa’s surface has marks that show the icy crust is vulnerable to the water below. The most important thing is that Juno’s recent visit shows what might be plume activity. If this is real, it would let future missions take samples of the ocean inside the planet without having to land.

Even though it’s been almost two years since Juno got the closest to Europa, its data is still being looked at. Even though Juno has been going around Jupiter since 2016, the five pictures it took on September 29, 2022, were the closest views of Europa since Galileo’s last visit in 2000.

Some might say that’s a shocking lack of interest in one of the Solar System’s most interesting worlds, but it could also have been a good way to see how things had changed over time.

Europa is the smoothest object in the solar system because its ocean keeps it from sinking to the surface. Still, it’s not featureless; Juno saw some deep depressions with steep walls that are 20 to 50 kilometers (12 to 31 miles) wide, as well as fracture patterns that are thought to show “true polar wander.

In a statement, Dr. Candy Hansen of the Planetary Science Institute said, “True polar wander occurs if Europa’s icy shell is separated from its rocky interior. This puts a lot of stress on the shell, which causes it to break in predictable ways.”

The shell that sits on top of Europa’s ocean is thought to be rotating faster than the rest of the moon. This is what true polar wandering means. People think that the water below is moving and pulling the shell along with it. Ocean currents are thought to be causing this. The currents are most likely a result of heat inside Europa’s rocky core, which is heated up as a result of Jupiter and its larger moons pulling on Europa and turning it into a large stress ball.

The ocean and ice could stretch and compress parts of the ice, which is how the cracks and ridges that have been seen since Voyager 2 visited were made.

A group under the direction of Hansen is viewing images of Europa’s southern half. The scientist said, “This is the first time that these fracture patterns have been mapped in the southern hemisphere. This suggests that true polar wander has a bigger effect on Europa’s surface geology than was thought before.”

Ocean currents are not to blame for all of Europa’s map changes. It appears that optical tricks can even fool NASA. Hansen said, “Crater Gwern is no longer there.” “JunoCam data showed that Gwern, which was once thought to be a 13-mile-wide impact crater and one of Europa’s few known impact craters, was actually a group of ridges that crossed each other to make an oval shadow.”

But Juno gives more than it takes away. The team is interested in what they’re calling the Platypus because of its shape, not because it has a lot of parts that shouldn’t go together. Ridges on its edge look like they are collapsing into it. The scientists think this might be because pockets of salt water have partially broken through the icy shell.

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The Europa Clipper would find these pockets to be fascinating indirect targets for study, but the dark stains that cryovolcanic activity might have left behind are even more intriguing.

“These features suggest the possibility of current surface activity and the existence of liquid water beneath the surface on Europa,” stated Heidi Becker from the Jet Propulsion Laboratory. There is evidence of such activity in the geysers of Enceladus, but there is still uncertainty regarding whether it is currently happening on Europa.

Engaging in such an endeavor would enable the sampling of the interior ocean to detect signs of life simply by flying through a plume and gathering ice flakes without the need for landing or drilling.

It seems that in the past, there was a significant shift of over 70 degrees in the locations of features on Europa’s surface, although the reasons for this remain unknown. However, at present, polar wander only leads to minor adjustments.

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Astronomy

The Sun emitted the largest solar flare in the past 20 years, resulting in power outages

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Solar Cycle 25 is decidedly more turbulent than its predecessor. The Sun is currently experiencing heightened activity, characterized by solar storms, coronal mass ejections, and geomagnetic storms of unprecedented intensity in recent years. Currently, the sun has emitted its most powerful solar flare to date during this particular cycle.

The flare was quantified as an X8.7, indicating a considerably higher strength compared to the flares emitted last week. The event emitted highly energetic light in the extreme ultraviolet range, which resulted in the ionization of the uppermost layer of the atmosphere. Consequently, a radio blackout occurred over the Americas, adversely impacting aircraft and vessels that depend on signals with frequencies below 30 MHz.

Ionization of the atmosphere causes an expansion, resulting in increased drag on satellites in low Earth orbit. They will require strategic maneuvering to be moved away from Earth. Solar flares have the potential to interfere with satellite communications.

A gif of the Sun yesterday with two bright flashes corresponding to the flares on its limb

Sunspot AR 3664 is where it comes from. Last week, several strong flares were seen coming from this area, including the second strongest of this cycle at the time. The Sun also sent out a number of coronal mass ejections (CMEs), which hit Earth and caused the beautiful auroral display we saw last weekend.

Back then, the sunspot was right on the side of the Sun that could be seen, and anyone could see it. It’s sixteen times wider than Earth! As the Sun turns, the spot is now on its side, so we can only see it from the side. We might have seen a bigger flare if it had happened last week.

“Another X-ray flare was made by Region 3664 as it moved past the western solar limb!!” It was an X8.7 flare this time, the biggest of this solar cycle! NASA’s Space Weather Prediction Center said in a post that any coronal mass ejection (CME) linked to this flare “likely WILL NOT have any geomagnetic effects on Earth due to its location.” “As always, please check our website for news!”

Today, as the CME moves past Earth, there may be a small rise in auroral activity. It’s too bad that nothing as exciting will happen as last Friday.

The solar cycle has a high point and a low point every 11 years. Around the peak, which could happen at any time, the most intense events tend to happen, but every once in a while, there are exceptions. There have been 10 times as many powerful flares this century.

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Astronomy

This planet like Earth is the first one that has been proven to have an atmosphere

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Astronomers have successfully utilized the James Webb Space Telescope (JWST) to observe the presence of an atmosphere around a terrestrial exoplanet, marking the first such discovery beyond our solar system. Despite its inability to sustain life due to its likely magma ocean, this planet could provide valuable insights into the early geological development of Earth, as both planets share a rocky composition and a history of being molten.

Sara Seager, a planetary scientist at the Massachusetts Institute of Technology in Cambridge who was not part of the study, states that the discovery of a gaseous envelope surrounding an Earth-like planet is a significant achievement in the field of exoplanet research. The Earth’s tenuous atmosphere plays a vital role in supporting life, and the ability to detect atmospheres on comparable rocky planets is a significant milestone in the quest for extraterrestrial life.

JWST is currently studying the planet 55 Cancri e, which orbits a star similar to the Sun at a distance of 12.6 parsecs. It is classified as a super-Earth, meaning it is a terrestrial planet slightly larger than Earth. Specifically, it has a radius approximately twice that of Earth and a mass more than eight times greater. The paper published in Nature1 suggests that the atmosphere of the planet is likely to contain significant amounts of carbon dioxide or carbon monoxide. Additionally, the thickness of the atmosphere is estimated to be “up to a few percent” of the planet’s radius.

A mysterious world
55 Cancri e is also not a good place to live because it is very close to its star—about 1.6 times as close as Earth is to the Sun. Still, Aaron Bello-Arufe, an astrophysicist at the Jet Propulsion Laboratory (JPL) in Pasadena, California, and a co-author of the paper, says, “it’s perhaps the most studied rocky planet.” Its host star is bright at night, and the planet is big for a rocky one, so it’s easier to study than other places outside of the Solar System. “In astronomy, every telescope or other tool you can think of has pointed to this planet at some point,” says Bello-Arufe.

55 Cancribe was studied so much that when JWST was launched in December 2021, engineers pointed the infrared spectrometers of the spacecraft at it to test it. As these instruments soak up infrared wavelengths from starlight, they can find the chemical signatures of gases swirling around planets. Then Bello-Arufe and his coworkers chose to look into it more to find out for sure if the planet had an atmosphere.

Astronomers had changed their minds about 55 Cancri a huge number of times before the most recent observations. In 2004, the planet was found. Scientists first thought it might be the center of a gas giant like Jupiter. Researchers looked at 55 Cancri e as it passed in front of its star3 with the Spitzer Space Telescope in 2011. They found that it is a rocky super-Earth, much smaller and denser than a gas giant.

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After some time, scientists found that 55 C was cooler than it should have been for a planet that was so close to its star. This suggests that it probably has an atmosphere. One hypothesis was that the planet is a “water world” with supercritical water molecules all around it. Another was that it has a large, primordial atmosphere mostly made up of hydrogen and helium. But in the end, these ideas were shown to be wrong.

According to Renyu Hu, a planetary scientist at JPL and co-author of the new study, stellar winds would make it difficult for a planet this close to its star to retain volatile molecules in its atmosphere. He says there are still two options. The first was that the planet is completely dry and has a very thin layer of rock vapor in the air. The second reason was that it has a thick atmosphere made up of heavier, less volatile molecules that don’t easily escape.

A better picture
The most recent information shows that 55 Cancrie’s atmosphere has gases made of carbon, which points to option two. Seager says that the team did indeed find evidence of an atmosphere but that more observations are needed to fully understand its make-up, the amounts of gases present, and its exact thickness.

Laura Schaefer is a planetary geologist at California’s Stanford University. She wants to know how the atmosphere of 55 Cancrie affects things below the surface of the planet. The authors of the study say it’s still possible that stellar winds are carrying away parts of the atmosphere. However, rocks melting and releasing gases into the magma ocean could replace the gases.

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