mckitterick: (meteor)
( May. 7th, 2017 12:37 pm)

NASA’s Cassini spacecraft scientists announce that a form of chemical energy that can feed life appears to exist on Saturn’s moon Enceladus, and Hubble researchers report additional evidence of plumes erupting from Jupiter’s moon Europa.

“This is the closest we’ve come, so far, to identifying a place with some of the ingredients needed for a habitable environment,” said Thomas Zurbuchen of NASA’s Science Mission Directorate.

“These results demonstrate the interconnected nature of NASA’s science missions that are getting us closer to answering whether we are alone or not.”

Hydrogen gas could potentially provide a chemical energy source for life, and it’s pouring into the subsurface ocean of Enceladus from hydrothermal activity on the seafloor. Ample hydrogen means that microbes – if any exist there – could use it to obtain energy by combining the hydrogen with carbon dioxide dissolved in the water.

This chemical reaction, known as “methanogenesis” because it produces methane as a byproduct, is at the root of the tree of life on Earth, and could even have been critical to the origin of life on our planet (see deep-ocean life that’s billions of years old).

Life as we know it requires three primary ingredients: liquid water, a source of energy for metabolism, and the right chemical ingredients - primarily carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.

With this finding, Cassini shows that Enceladus – a small, icy moon a billion miles farther from the Sun than Earth – has nearly all of these ingredients for habitability. Cassini has not yet proven that phosphorus and sulfur are present in the ocean, but scientists suspect them to be, because the rocky core of Enceladus is thought to be chemically similar to other bodies that contain these elements.

“Confirmation that the chemical energy for life exists within the ocean of a small moon of Saturn is an important milestone in our search for habitable worlds beyond Earth,” said Linda Spilker, Cassini project scientist at JPL).


Full story: X

Lots more Cassini photos of Enceladus: X

Today is the 25th anniversary of Hubble Space Telescope’s launch! NASA is celebrating with a special Hubble 25th website: x. Hover over the photos below for info.

This one's the hero of our story:

Westerlund 2 in Carina: star-forming region of 3000 stars
Tadpole Galaxy
Carina Nebula panorama
Baby planets in the Orion Nebula!
Two colliding spiral galaxies called "The Antennae."
Hubble revisits one of its most famous subjects, aka "The Pillars of Creation."
All those little dark bumps are going to be baby stars one day.

Want to see all the best photos? Check out the Hubble Heritage Site for billions more: x
Did you know that lots of asteroids have moons? Check it out:

Scientists working with NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California, have released the first radar images of asteroid 2004 BL86. (These are also the folks responsible for the New Horizons mission to Pluto, which arrives soon!)

The resolution on the radar images is 13 feet (4 meters) per pixel. It made its closest approach yesterday (January 26, 2015, 10:19 am Central time) just 745,000 miles (1.2 million kilometers) from us, about 3.1 times the distance as far away as the Moon.

Best part? The images reveal that asteroid 2004 BL86 has its own small moon.

The asteroid is approximately 1,100 feet (325 meters) across and has a small moon approximately 230 feet (70 meters) across. In the near-Earth-object (NEO) population, about 16 percent of asteroids larger than 650 feet (200 meters) or larger have one - or even two! - small moons orbiting them.

The trajectory of the asteroid is well understood. Monday's flyby was the closest approach the asteroid will make to Earth for at least the next two centuries. It is also the closest a known asteroid this size will come to Earth until asteroid 1999 AN10 flies past our planet in 2027.

Asteroid 2004 BL86 was discovered on Jan. 30, 2004, by the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, New Mexico.

NASA places a high priority on tracking asteroids and protecting our home planet from them, the most robust and productive survey and detection program for discovering NEOs in the world. NASA partners with government agencies, university-based astronomers, space science institutes across the country, and amateur astronomers, plus international space agencies and institutions working to track and better understand these objects. (I helped with the NEO search, too, back in the mid-1990s, as part of the Hobbs Observatory mission. That was frakkin' cool, except the part where I had to use an Apple II to run the telescope.)

Snips from a couple of amateur vids:

This tiny little world has a moon of its own! Space exploration is awesome.

Speaking of, The Galactic Adventures of Jack & Stella progress:

Have you ever seen anything more astounding or beautiful than Saturn's hexagonal storm system in its north pole?

The eye of this storm is about 50 times larger than the average hurricane eye on Earth. Winds are measured by following small clouds over a five-hour period. The winds at the inner ring are moving the fastest, at speeds of about 340 mph (550 kph) relative to the nominal rate for the planet established by NASA's Voyager spacecraft in 1980. These winds are four times the speed of the Earth's jet streams and more than four times the definition of a hurricane force wind on Earth. (Hurricane force winds blow at 74 mph, or 119 kph.)

The clouds at the very center are spinning rapidly - almost twice as fast as the planet itself, with a period just over six hours. The direction of rotation is counterclockwise, like a northern hemisphere hurricane on Earth, except there is no ocean underneath. A similar feature exists at Saturn’s southern pole, and it spins in the same direction as that of a southern hemisphere hurricane on Earth. However, the hurricanes on Earth begin in the tropics and drift around. The polar hurricanes on Saturn are locked to their poles.

The bright clouds form a tightly wrapped spiral that traces a path toward the center as one follows it in a counterclockwise direction. This spiral could be a wave or actual particle motion toward the center from a disturbance further out. Or it could be the remnants of a compact cloud that got sheared apart by the higher angular velocity closer to the center. Choosing among these possibilities is the subject of ongoing research.

NASA also has a great little video of this massive, freakishly shaped hurricane here.

Source: NASA's Cassini mission.


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