Purple Bacteria — Not Green Plants — Might Be the Strongest Indication of Life

Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity. Credit: Oleg Kuznetsov
Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity, and distant exoplanets might begin similarly. Credit: Oleg Kuznetsov

Astrobiologists continue to work towards determining which biosignatures might be best to look for when searching for life on other worlds. The most common idea has been to search for evidence of plants that use the green pigment chlorophyll, like we have on Earth. However, a new paper suggests that bacteria with purple pigments could flourish under a broader range of environments than their green cousins. That means current and next-generation telescopes should be looking for the emissions of purple lifeforms.

“Purple bacteria can thrive under a wide range of conditions, making it one of the primary contenders for life that could dominate a variety of worlds,” said Lígia Fonseca Coelho, a postdoctoral associate at the Carl Sagan Institute (CSI) and first author of “Purple is the New Green: Biopigments and Spectra of Earth-like Purple Worlds,” published in the Monthly Notices of the Royal Astronomical Society: Letters.

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Juno Reveals a Giant Lava Lake on Io

An artists rendition of Loki Patera, a lava lake on Jupiter’s moon Io. Credit: NASA.

NASA’s Juno spacecraft came within 1,500 km (930 miles) of the surface of Jupiter’s moon Io in two recent flybys. That’s close enough to reveal new details on the surface of this moon, the most volcanic object in the Solar System. Not only did Juno capture volcanic activity, but scientists were also able to create a visual animation from the data that shows what Io’s 200-km-long lava lake Loki Patera would look like if you could get even closer. There are islands at the center of a magma lake rimmed with hot lava. The lake’s surface is smooth as glass, like obsidian.

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Someone Just Found SOHO's 5,000th Comet

The 5,000th comet discovered with the Solar and Heliospheric Observatory (SOHO) spacecraft is noted by a small white box in the upper left portion of this image. A zoomed-in inset shows the comet as a faint dot between the white vertical lines. The image was taken on March 25, 2024, by SOHO’s Large Angle and Spectrometric Coronagraph (LASCO), which uses a disk to block the bright Sun and reveal faint features around it. Credit: NASA/ESA/SOHO

The Solar and Heliospheric Observatory (SOHO) was designed to examine the Sun, but as a side benefit, it has been the most successful comet hunter ever built. Since early in the mission, citizen scientists have been scanning through the telescope’s data, searching for icy objects passing close to the Sun. An astronomy student in Czechia has identified 200 comets in SOHO data since he started in 2009 at the age of 13. He recently spotted the observatory’s 5,000th comet.

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NASA Reveals its Planetary Science Goals for Artemis III

Artist's illustration of Artemis III astronauts on the Moon. Credit: NASA.

If all goes well, NASA’s Artemis III mission will bring humans back to the Moon as early as 2026, the first time since the Apollo 17 crew departed in 1972. It won’t be a vacation, though, as astronauts have an enormous amount of science to do, especially in lunar geology. A team from NASA recently presented their planetary science goals and objectives for Artemis III surface activities, which will guide the fieldwork the astronauts will carry out on the lunar surface.

The Artemis III Geology Team presented their priorities at the Lunar and Planetary Science Conference in March 2024. In addition, NASA also announced their choices for the first science instruments that astronauts will deploy on the surface of the Moon during Artemis III.

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Gaia Finds Ancient Streams of Stars That Formed the Milky Way

ESA’s Gaia space telescope discovered two star streams that helped form the infant Milky Way. Both are so ancient that they likely formed before even the oldest parts of our present-day galaxy’s spiral arms and disc. This image shows the location and distribution of Shakti (yellow) and Shiva (blue) stars throughout the Milky Way. Credit: ESA/Gaia/DPAC/K. Malhan.

Using ESA’s Gaia spacecraft, astronomers have tracked down two streams of stars that likely formed the foundation of the Milky Way. Named “Shakti and Shiva,” the two streams contain about 10 million stars, all of which are 12 to 13 billion years old and likely came together even before the spiral arms and disk were formed. These star streams are all moving in roughly similar orbits and have similar compositions. Astronomers think they were probably separate galaxies that merged into the Milky Way shortly after the Big Bang.,

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The Mars Science Helicopter Could be an Airborne Geologist on Mars

A model of NASA’s Mars Science Helicopter concept. Credit: NASA.

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.

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Improving a 1960s Plan to Explore the Giant Planets

John Bodylski holds a balsa wood model of his proposed aircraft that could be an atmospheric probe. Directly in front of him is a fully assembled version of the aircraft and a large section of a second prototype at NASA’s Armstrong Flight Research Center in Edwards, California. Credit: NASA/Steve Freeman

In the 1960s, NASA engineers developed a series of small lifting-body aircraft that could be dropped into the atmosphere of a giant planet, measuring the environment as they glided down. Although it would be a one-way trip to destruction, the form factor would allow a probe to glide around in different atmospheric layers, gathering data and transmitting it back to a parent satellite. An updated version of the 1960s design is being tested at NASA now, and a drop-test flight from a helicopter is scheduled for this month.

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It's Time for Jupiter's Annual Checkup by Hubble

Jupiter as seen by the Hubble Space Telescope on January 5 and 6, 2024. Credit: NASA/ESA/Space Telescope Science Institute.

Each year, the Hubble Space Telescope focuses on the giant planets in our Solar System when they’re near the closest point to Earth, which means they’ll be large and bright in the sky. Jupiter had its photos taken on January 5-6th, 2024, showing off both sides of the planet. Hubble was looking for storm activity and changes in Jupiter’s atmosphere.

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Astronomers Image 62 Newly-Forming Planetary Systems

Planet-forming discs in three clouds of the Milky Way. Credit: ESO.

Astronomers using the Very Large Telescope in Chile have now completed one of the largest surveys ever to hunt for planet-forming discs. They were able to find dozens of dusty regions around young stars, directly imaging the swirling gas and dust which hints at the locations of these new worlds.

Just like the wide variety in the types of exoplanets that have been discovered, these new data and stunning images show how protoplanetary systems are surprisingly diverse, with different sizes and shapes of disks.

In research presented in three new papers, researchers imaged 86 young stars and found 62 of them had a wide range of star-forming regions surrounding them. The astronomers say this study provides a wealth of data and unique insights into how planets arise in different regions of our galaxy.

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Now You Can See Exactly Where Hubble and JWST are Pointed

Graphics of the Hubble and James Webb Space Telescopes. Credit: NASA/STScI.

Hubble and JWST are busily scanning the sky, sending home enormous amounts of data. They shift from target to target, completing the required observations.

But have you ever wondered what those two space telescopes are doing right at this moment? Now, you can do just that at the new Space Telescope Live website. It will show you what each observatory is scanning, where the objects are in the sky, and what researchers hope to learn. You can even go back or forward in time and see what each telescope has been looking at in the past or what observations are coming up.

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