This illustration shows what exoplanet K2-18 b could look like based on science data. NASA’s James Webb Space Telescope examined the exoplanet and revealed the presence of carbon-bearing molecules. The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b. But more extensive observations with the JWST are needed to understand its atmosphere with greater confidence. Image Credit: By Illustration: NASA, ESA, CSA, Joseph Olmsted (STScI)Science: Nikku Madhusudhan (IoA)
In the search for potentially life-supporting exoplanets, liquid water is the key indicator. Life on Earth requires liquid water, and scientists strongly believe the same is true elsewhere. But from a great distance, it’s difficult to tell what worlds have oceans of water. Some of them can have lava oceans instead, and getting the two confused is a barrier to understanding exoplanets, water, and habitability more clearly.
The moons of Saturn, from left to right: Mimas, Enceladus, Tethys, Dione, Rhea; Titan in the background; Iapetus (top) and irregularly shaped Hyperion (bottom). Some small moons are also shown. All to scale. Credit: NASA/JPL/Space Science Institute
Continuing with our “Definitive Guide to Terraforming“, Universe Today is happy to present our guide to terraforming Saturn’s Moons. Beyond the inner Solar System and the Jovian Moons, Saturn has numerous satellites that could be transformed. But should they be?
Around the distant gas giant Saturn lies a system of rings and moons that is unrivaled in terms of beauty. Within this system, there is also enough resources that if humanity were to harness them – i.e. if the issues of transport and infrastructure could be addressed – we would be living in an age a post-scarcity. But on top of that, many of these moons might even be suited to terraforming, where they would be transformed to accommodate human settlers.
As with the case for terraforming Jupiter’s moons, or the terrestrial planets of Mars and Venus, doing so presents many advantages and challenges. At the same time, it presents many moral and ethical dilemmas. And between all of that, terraforming Saturn’s moons would require a massive commitment in time, energy and resources, not to mention reliance on some advanced technologies (some of which haven’t been invented yet).
Pluto’s Majestic Mountains, Frozen Plains and Foggy Hazes: Just 15 minutes after its closest approach to Pluto on July 14, 2015, NASA’s New Horizons spacecraft looked back toward the sun and captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The smooth expanse of the informally named icy plain Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 11,000 feet (3,500 meters) high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. To the right, east of Sputnik, rougher terrain is cut by apparent glaciers. The backlighting highlights over a dozen layers of haze in Pluto’s tenuous but distended atmosphere. The image was taken from a distance of 11,000 miles (18,000 kilometers) to Pluto; the scene is 780 miles (1,250 kilometers) wide.
Credits: NASA/JHUAPL/SwRI
As the hazy, lazy days of summer come to a close, the New Horizons team released a brand new set of incredible images of a very atmospheric Pluto.
Can you believe the detail in these photos? Back-lit by the Sun, we see icy plains, rugged mountains, glacier-cut terrain and multiple layers of haze just like those on a steamy August afternoon.
Just look at those pyramidal mountain peaks right next to those relatively smooth, icy plains. The backlighting highlights more than a dozen layers of haze in Pluto’s tenuous but distended atmosphere. The image was taken from a distance of 11,000 miles (18,000 km) to Pluto; the scene is 230 miles (380 km) across. Credits: NASA/JHUAPL/SwRI)
The scene measures 780 miles (1,250 kilometers) across and was taken from a distance of 11,000 miles (18,000 km) on July 15 just after closest approach. Because backlighting highlights fine aerosols suspended in the atmosphere (think of seeing your breath on a cold winter day against the Sun), these photos show the amazing complexity of Pluto’s atmosphere with more than a dozen thin haze layers extending from near the ground to at least 60 miles (100 km) above the surface.
In this small section of the larger crescent image of Pluto, the setting sun illuminates a bank of fog or low-lying near-surface haze sliced by the parallel shadows of many local hills and small mountains. The image was taken from a distance of 11,000 miles (18,000 km), and the width of the image is 115 miles (185 km). Credits: NASA/JHUAPL/SwRI
“This image really makes you feel you are there, at Pluto, surveying the landscape for yourself,” said New Horizons Principal Investigator Alan Stern in a press release today. “But this image is also a scientific bonanza, revealing new details about Pluto’s atmosphere, mountains, glaciers and plains.”
Sputnik Planum is the informal name of the smooth, light-bulb shaped region on the left of this composite of several New Horizons images of Pluto. The brilliantly white upland region to the right may be coated by nitrogen ice that has been transported through the atmosphere from the surface of Sputnik Planum, and deposited on these uplands. The box shows the location of the glacier detail images below. Credits: NASA/JHUAPL/SwRI
I find the hazes the most amazing aspect of the photos. They remind me of crepuscular rays, those beams of sunshine that shine between breaks in the clouds near sunset and sunrise. It chills and thrills me to the bone to see such earthly sights on a bitterly cold orb more than 3 billion miles from home.
Ice, probably frozen nitrogen, appears to have accumulated on the uplands on the right side of this 390-mile (630-km) wide image is draining from Pluto’s mountains onto the informally named Sputnik Planum through the 2- to 5-mile (3- to 8-km) wide valleys indicated by the red arrows. On Earth this would be considered a valley glacier. The flow front of the ice moving into Sputnik Planum is outlined by the blue arrows. The origin of the ridges and pits on the right side of the image remains uncertain. Credits: NASA/JHUAPL/SwRI
But that’s not all that’s close to our hearts on Pluto. The photos reveal nitrogen ice apparently flowing downhill from mountainous highlands into a broad, smooth basin. Combined with other recently downloaded pictures, this new image (above) provides evidence for a remarkably Earth-like “hydrological” cycle on Pluto – but involving soft and exotic ices, including nitrogen, rather than water ice.
This might be the most remarkable image of all. It covers the same region as the image above, but is re-projected from the oblique, backlit view shown in the new crescent image of Pluto. The backlighting highlights the intricate flow lines on the valley glaciers. The flow front of the ice moving into the informally named Sputnik Planum is outlined by the blue arrows. We’re looking at a scene 390 miles (630 km) across. Credits: NASA/JHUAPL/SwRI
Nitrogen ice in the vast, relatively smooth Sputnik Planum may have vaporized in sunlight and then redeposited as ice in the bright, rugged region to its east. The new Ralph imager panorama also reveals glaciers flowing back from the blanketed mountain region into Sputnik Planum; these features are similar to the frozen streams on the margins of ice caps on Greenland and Antarctica.
Who knew that by going to Pluto we’d see such familiarity? But there you have it.
Spectacular photo of Comet ISON taken Nov. 15 from Charleston, Rhode Island, USA showing the recent outburst. Click to enlarge. Credit: Scott MacNeill
Comet ISON — that bright comet last year that broke up around Thanksgiving weekend — included two forms of nitrogen in its icy body, according to newly released observations from the Subaru Telescope.
Of the two types found, the discovery of isotope 15NH2 was the first time it’s ever been seen in a comet. Further, the observations from the Japanese team of astronomers show “there were two distinct reservoirs of nitrogen [in] the massive, dense cloud … from which our Solar System may have formed and evolved,” stated the National Astronomical Observatory of Japan.
Besides being pretty objects to look at, comets are considered valuable astronomical objects because they’re a sort of time capsule of conditions early in the universe. The “fresh” comets are believed to come from a vast area of icy bodies called the Oort Cloud, a spot that has been relatively untouched since the solar system formed about 4.6 billion years ago. Spying elements inside of comets can give clues as to what was present in our neighborhood when the sun and planets were just coming to be.
“Ammonia (NH3) is a particularly important molecule, because it is the most abundant nitrogen-bearing volatile (a substance that vaporizes) in cometary ice and one of the simplest molecules in an amino group (–NH2) closely related to life. This means that these different forms of nitrogen could link the components of interstellar space to life on Earth as we know it,” NAOJ stated.
You can read more details about the finding at the NAOJ website, or in Astrophysical Journal Letters.
Ancient comets may have created Titan's nitrogen-rich atmosphere
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Titan is a fascinating world to planetary scientists. Although it’s a moon of Saturn it boasts an opaque atmosphere ten times thicker than Earth’s and a hydrologic cycle similar to our own – except with frigid liquid methane as the key component instead of water. Titan has even been called a living model of early Earth, even insofar as containing large amounts of nitrogen in its atmosphere much like our own. Scientists have wondered at the source of Titan’s nitrogen-rich atmosphere, and now a team at the University of Tokyo has offered up an intriguing answer: it may have come from comets.
Traditional models have assumed that Titan’s atmosphere was created by volcanic activity or the effect of solar UV radiation. But these rely on Titan having been much warmer in the past than it is now…a scenario that Cassini mission scientists don’t think is the case.
New research suggests that comet impacts during a period called the Late Heavy Bombardment – a time nearly 4 billion years ago when collisions by large bodies such as comets and asteroids were occurring regularly among worlds in our solar system – may have generated Titan’s nitrogen atmosphere. By firing lasers into ammonia-and-water-ice material similar to what would have been found on primordial Titan, researchers saw that nitrogen was a typical result. Over the millennia these impacts could have created enough nitrogen to cover the moon in a dense haze, forming the thick atmosphere we see today.
“We propose that Titan’s nitrogen atmosphere formed after accretion, by the conversion from ammonia that was already present on Titan during the period of late heavy bombardment about four billion years ago.”
– Yasuhito Sekine et al., University of Tokyo, Japan
This model, if true, would also mean that the source of Titan’s nitrogen would be different than that of other outer worlds, like Pluto, and even inner planets like our own.
Top image is a combination of a color-composite of Titan made from raw Cassini data taken on October 12, 2010 and a recolored infrared image of the comet Siding Spring, taken by NASA’s WISE observatory on January 10, 2010. The background stars were also taken by the Cassini orbiter. NASA / JPL / SSI and Caltech/UCLA. Edited by J. Major.
Note: the image at top is not scientifically accurate…the comet’s tail would be, based on the lighting of Titan, pointing more to the ten o’clock position as well as forward toward the viewer’s left shoulder. This would make it ‘look’ as if it were going the opposite direction though, away from Titan, and so I went with the more immediately decipherable version seen here. To see a more “realistic” version, click here.
