The James Webb Space Telescope has recently made some intriguing discoveries while observing the exoplanet K2-18 b, leading to speculations about the presence of life. NASA announced on September 11, 2023, that K2-18 b possesses methane and carbon dioxide in its atmosphere, suggesting it may be a Hycean world—a planet with a deep hydrogen atmosphere and a global water ocean. However, the most remarkable finding was the detection of dimethyl sulfide (DMS), a molecule typically produced by life forms like bacteria and phytoplankton in Earth’s oceans.

While this discovery is exciting, it is essential to note that further confirmation is required regarding the presence of DMS. Additionally, scientists need to learn more about the exoplanet before drawing definitive conclusions about the existence of life on K2-18 b. Although it resides within the habitable zone of its star, environmental factors could still render it inhospitable. NASA has suggested that the planet’s active star might create a hostile environment, and its ocean may be excessively hot for life to thrive. Nonetheless, these findings are undeniably tantalizing and warrant further exploration.

K2-18 b orbits a red dwarf star approximately 124 light-years away in the Leo constellation. The habitable zone refers to the region around a star where temperatures are suitable for liquid water to exist. While K2-18 b’s position within this zone does not definitively prove habitability, the new data from the Webb Telescope supports the possibility.

In addition to the potential ocean and the presence of methane and carbon dioxide, the detection of dimethyl sulfide in K2-18 b’s atmosphere is particularly intriguing. On Earth, this organic sulfur compound is exclusively produced through biological processes by organisms such as bacteria and phytoplankton in marine environments.

To summarize, the James Webb Space Telescope’s observations of exoplanet K2-18 b have unveiled exciting clues that hint at the possibility of life. The presence of methane, carbon dioxide, a potential ocean, and the detection of dimethyl sulfide spark further curiosity and exploration. However, more research and confirmation are needed to ascertain the existence of life on this distant world. The discoveries made by Webb have undoubtedly ignited our imagination and drive to unravel the mysteries of the universe.

To know more about the topic, kindly refer to this article. https://earthsky.org/space/webb-k2-18-b-exoplanet-hycean-biosignature/?mc_cid=2d1c8d717b&mc_eid=36fb49e54a

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Newswise — LOS ALAMOS, N.M.—New observations of mud cracks made by the Curiosity Rover show that high-frequency, wet-dry cycling occurred in early Martian surface environments, indicating that the red planet may have once seen seasonal weather patterns or even flash floods. The research was published today in Nature.

“These exciting observations of mature mud cracks are allowing us to fill in some of the missing history of water on Mars. How did Mars go from a warm, wet planet to the cold, dry place we know today? These mud cracks show us that transitional time, when liquid water was less abundant but still active on the Martian surface,” said Nina Lanza, principal investigator of the ChemCam instrument onboard the Curiosity Rover. “These features also point to the existence of wet-dry environments that on Earth are extremely conducive to the development of organic molecules and potentially life. Taken as a whole, these results a giving us a clearer picture of Mars as a habitable world.”

The presence of long-term wet environments, such as evidence of ancient lakes on Mars, is well-documented, but far less is known about short-term climate fluctuations.

After years of exploring terrain largely comprised of silicates, the rover entered a new area filled with sulfates, marking a major environment transition. In this new environment, the research team found a change in mud crack patterns, signifying a change in the way the surface would have dried. This indicates that water was still present on the surface of Mars episodically, meaning water could have been present for a time, evaporated, and repeated until polygons, or mud cracks, formed.

“A major focus of the Curiosity mission, and one of the main reasons for selecting Gale Crater, is to understand the transition of a ‘warm and wet’ ancient Mars to a ‘cold and dry’ Mars we see today,” said Patrick Gasda of the Laboratory’s Space Remote Sensing and Data Science group and coauthor of the paper. “The rover’s drive from clay lakebed sediments to drier non-lakebed and sulfate-rich sediments is part of this transition.”

On Earth, initial mud cracks in mud form a T-shaped pattern, but subsequent wetting and drying cycles cause the cracks to form more of a Y-shaped pattern, which is what Curiosity observed. Additionally, the rover found evidence that the mud cracks were only a few centimeters deep, which could mean that wet-dry cycles were seasonal, or may have even occurred more quickly, such as in a flash flood. 

These findings could mean that Mars once had an Earth-like wet climate, with seasonal or short-term flooding, and that Mars may have been able to support life at some point.  

“What’s important about this phenomenon is that it’s the perfect place for the formation of polymeric molecules required for life, including proteins and RNA, if the right organic molecules were present at this location,” Gasda said “Wet periods bring molecules together while dry periods drive reactions to form polymers. When these processes occur repeatedly at the same location, the chance increases that more complex molecules formed there.”

The paper: “Sustained wet-dry cycling on early Mars.” Nature. DOI: 10.1038/s41586-023-06220-3

Funding:  NASA’s Mars Exploration Program and in France is conducted under the authority of CNES. Mastcam mosaics were processed by the Mastcam team at Malin Space Science Systems. Edwin Kite funding by NASA grant 80NSSC22K0731. Lucy Thompson funding as MSL team member is provided by the CSA.

Journal Link: Nature

Source: Los Alamos National Laboratory

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Exciting news for astronomy enthusiasts! On August 11, Japanese amateur astronomer Hideo Nishimura made a remarkable discovery—a bright object near the Sun that turned out to be a brand-new comet. Officially named C/2023 P1 (Nishimura) by the Minor Planet Center on August 15, this comet has been gradually brightening and captivating stargazers worldwide. Let’s explore what we know about this celestial visitor and how you can catch a glimpse of its awe-inspiring journey.

Current Appearance and Observation:
Presently located in the constellation Gemini, C/2023 P1 has reached a magnitude of 10.8 and is steadily growing brighter. The comet boasts an impressive tail, stretching nearly 8′ in length. With an amateur 6-inch telescope, you can observe C/2023 P1 for a few hours before dawn, adding a touch of celestial wonder to your stargazing experience.

Decoding the Name:
The name C/2023 P1 (Nishimura) provides valuable information about the comet’s discovery:

• The letter C signifies that it is a non-periodic comet originating from the Oort cloud and may pass through the Solar System only once or take hundreds to thousands of years to complete an orbit around the Sun.
• “2023 P1” indicates the year and time of discovery—August in this case—and signifies that it was the first such object discovered during that period.
• “Nishimura” pays tribute to the Japanese astronomer Hideo Nishimura, who made this remarkable find.

Finding C/2023 P1 (Nishimura) in the Sky:
Locating the comet is made easier with astronomy apps like Star Walk 2 and Sky Tonight. By following these simple steps, you can track its position:

1. Launch the app and tap the magnifying glass icon.
2. Enter “C/2023 P1” in the search field and select the appropriate result.
3. Utilize the compass button or point your device at the sky to align the screen with your surroundings.
4. Follow the arrow on the screen to locate the comet in the real sky, as directed by the app.

Path and Best Viewing Time:
Here are some upcoming milestones in the comet’s path:

• August 26: C/2023 P1 (mag 9.2) enters the constellation Cancer.
• September 5: C/2023 P1 (mag 6.9) enters the constellation Leo.
• September 7: C/2023 P1 (mag 6.3) passes 0°16′ away from the star Ras Elased Australis (mag 3.0) in the constellation Leo.
• September 9: C/2023 P1 (mag 5.6) passes 0°20′ away from the star Adhafera (mag 3.4) in the constellation Leo.
• September 15: C/2023 P1 (mag 3.7) passes 0°10′ away from the star Denebola (mag 2.1) in the constellation Leo.

The comet is expected to reach its brightest magnitude, 4.9, on September 11, making it visible to the naked eye. However, as it approaches perihelion, it will be closer to the Sun in the sky, which may pose a challenge in spotting it.

Perihelion and Beyond:
On September 18, C/2023 P1 will reach perihelion, its closest point to the Sun. As it approaches, the comet may shine as bright as 3.2 magnitude, becoming visible without the aid of telescopes. However, it will also be located only around 12° away from the Sun, limiting the observation window. While there is a possibility the comet may disintegrate during this phase, continued tracking is advised.

Don’t miss the opportunity to witness the stunning C/2023 P1 (Nishimura) comet as it approaches Earth. Utilize stargazing apps like Star Walk 2 or Sky Tonight to locate this celestial spectacle in the night sky. With its anticipated brightness, the comet may captivate viewers until mid-September before gradually fading from naked-eye visibility. Stay tuned for more astronomical wonders, as another bright comet, C/2023 A3 (Tsuchinshan-ATLAS), is expected to grace our skies in the coming months. Happy stargazing!

Click the link to find out more: https://starwalk.space/en/news/new-comet-c2023-p1

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Source: Skywalk