Radio and television broadcasting may be only a brief passing phase in our technological development. When we imagine alien civilizations broadcasting signals with radio telescopes, are we any different from earlier generations who imagined riding cannon shells to the moon? Civilizations even slightly more advanced than ours may have already moved on to some other mode of communication, one that we have yet to discover or even imagine. Their messages could be swirling all around us at this very moment, but we lack the means to perceive them just as all of our ancestors, up to a little more than a century ago, would have been oblivious to the most urgent radio signal from another world.
But there’s another more troubling possibility: Civilizations, like other living things, may only live so long before perishing due to natural causes, or violence, or self-inflicted wounds. Whether or not we ever make contact with intelligent alien life may depend on a critical question: What is the life expectancy of a civilization?
- Episode 11: The Immortals, Cosmos: A SpaceTime Odyssey
NASA just announced what the Mars 2020 rover will carry to the Martian surface, and one of them sounds like pure sci-fi: MOXIE, a machine that sucks in carbon dioxide from the Martian atmosphere and pumps out pure oxygen for use in rocket fuel—or someday, for humans to breathe.
"We’re not so much using the oxygen, but seeing can we generate it, what’s the production rate, what’s the efficiency. Those are the general kinds of things we’re looking at with this in-situ device. If you can make propellant for a craft’s ascent stage to get off Mars, that really changes the mission design. Or if you can cache and store oxygen before a crew arrives, and have a habitable environment when we get there."
Select illustrations from The Rocket (A Ladybird ‘How It Works’ Book). I missed out on Ladybird Books when I was a kid thus my current obsession collecting them.
A Ladybird ‘How It Works’ Book: The Rocket, series ‘654.’ Originally published in1967. Illustrated by B.H. Robinson.
Speed of a Planet’s Rotation Has Huge Effect on Possibility of Life
“Rotation can have a huge effect, and lots of planets that we previously thought were definitely not habitable now can be considered as candidates,” says Dorian Abbot of the University of Chicago. New research has revealed that the rate at which a planet spins is instrumental in its ability to support life. Not only does rotation control the length of day and night, it can also tug on the winds that blow through the atmosphere and ultimately influence cloud formation.
There are currently almost 2,000 extrasolar planets known to us, but most are inhospitable gas giants. Thanks to NASA’s Kepler mission, a handful of smaller, rockier planets have been discovered within the habitable zones of their stars that could provide a niche for alien life.
Twinkling worlds in motion:
New Horizons’ first optical navigation images of Pluto and Charon
Captuded by the high-powered Long-Range Reconnaissance Imager (LORRI)
Posted by Emily Lakdawalla at The Planetary Society 2014/08/07
Image credit: NASA / JHUAPL / SwRI
[TOP] This animation of Pluto and its largest moon, Charon, was taken by New Horizons spacecraft as it traveled toward Pluto in July 2014. Covering almost one full rotation of Charon around Pluto, the 12 images that make up the movie were taken July 19-24 with the Long Range Reconnaissance Imager (LORRI) at distances ranging from about 429 million to 422 million kilometers.
[MIDDLE] What I think is especially cool about this animation is the fact that you can clearly see that neither Pluto nor Charon is still; Charon’s mass is a large enough fraction of Pluto’s that both are in a mutual orbit around a point in empty space, above Pluto’s surface, called the system’s barycenter.
[BOTTOM] If you are wondering why Charon seems to be getting closer to and farther from Pluto, it’s because we’re looking at the system from an angle, so the circular motions of Pluto and Charon appear ellitpical.
Happy 10th Anniversary Cassini!
The Cassini mission celebrates 10 years of exploring Saturn, its rings and moons. Not only did it send back some of most incredible images ever produced, the spacecraft has also collected hundreds of gigabytes of scientific data, enabling the publication of more than 3,000 scientific reports. NASA’S JPL has compiled 10 of Cassini’s top accomplishments and discoveries:
- The Huygens probe makes first landing on a moon in the outer solar system (Titan)
- Discovery of active, icy plumes on the Saturnian moon Enceladus
- Saturn’s rings revealed as active and dynamic — a laboratory for how planets form
- Titan revealed as Earth-like world with rain, rivers, lakes and seas
- Studies of the great northern storm of 2010-2011
- Radio-wave patterns shown not to be tied to Saturn’s interior rotation as previously thought
- Vertical structures in the rings imaged for the first time
- Study of prebiotic chemistry on Titan
- Mystery of the dual bright-dark surface of Iapetus solved
- First complete view of the north polar hexagon and discovery of giant hurricanes at both of Saturn’s poles
We love you, Cassini!
Westerlund 2 in X-ray
Westerlund 2 is a young massive obscured star cluster with an estimated age of about one or two million years. It contains some of the hottest, brightest, and most massive stars known. The cluster contains a dozen of O stars, of which at least three are eclipsing binaries.
Titan is the largest moon of Saturn. It is the only natural satellite known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found
Titan is primarily composed of water ice and rocky material. Much as with Venus prior to the Space Age, the dense, opaque atmosphere prevented understanding of Titan’s surface until new information accumulated with the arrival of the Cassini–Huygens mission in 2004, including the discovery of liquid hydrocarbon lakes in Titan’s polar regions.
The atmosphere is largely nitrogen; minor components lead to the formation of methane and ethane clouds and nitrogen-rich organic smog. Titan’s lower gravity means that its atmosphere is far more extended than Earth’s and about 1.19 times as massive. It supports opaque haze layers that block most visible light from the Sun and other sources and renders Titan’s surface features obscure. Atmospheric methane creates a greenhouse effect on Titan’s surface, without which Titan would be far colder. Conversely, haze in Titan’s atmosphere contributes to an anti-greenhouse effect by reflecting sunlight back into space, cancelling a portion of the greenhouse effect warming and making its surface significantly colder than its upper atmosphere.
Titan’s clouds, probably composed of methane, ethane or other simple organics, are scattered and variable, punctuating the overall haze.The findings of the Huygens probe indicate that Titan’s atmosphere periodically rains liquid methane and other organic compounds onto its surface. Clouds typically cover 1% of Titan’s disk, though outburst events have been observed in which the cloud cover rapidly expands to as much as 8%. One hypothesis asserts that the southern clouds are formed when heightened levels of sunlight during the southern summer generate uplift in the atmosphere, resulting in convection. This explanation is complicated by the fact that cloud formation has been observed not only after the southern summer solstice but also during mid-spring.
Image Credit: NASA/JPL/Space Science Institute