Supermassive Black Holes Feed on Cosmic Jellyfish An Italian-led team of astronomers used the MUSE (Multi-Unit Spectroscopic Explorer) instrument on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile to study how gas can be stripped from galaxies. They focused on extreme examples […]
Curious Kids: Why don’t the planets closest to the Sun melt or burn up? While Mercury is indeed very hot, it is not hot enough to melt. NASA/JPL-Caltech, CC BY Chris Tinney, UNSW This is an article from Curious Kids, a series for children. The […]
Voyager Golden Records 40 years later: Real audience was always here on Earth
Forty years ago, NASA launched Voyager I and II to explore the outer solar system. The twin spacecraft both visited Jupiter and Saturn; from there Voyager I explored the hazy moon Titan, while Voyager II became the first (and, to date, only) probe to explore Uranus and Neptune. Since they move too quickly and have too little propellant to stop themselves, both spacecraft are now on what NASA calls their Interstellar Mission, exploring the space between the stars as they head out into the galaxy.
Both craft carry Golden Records: 12-inch phonographic gold-plated copper records, along with needles and cartridges, all designed to last indefinitely in interstellar space. Inscribed on the records’ covers are instructions for their use and a sort of “map” designed to describe the Earth’s location in the galaxy in a way that extraterrestrials might understand.
The grooves of the records record both ordinary audio and 115 encoded images. A team led by astronomer Carl Sagan selected the contents, chosen to embody a message representative of all of humanity. They settled on elements such as audio greetings in 55 languages, the brain waves of “a young woman in love” (actually the project’s creative director Ann Druyan, days after falling in love with Carl Sagan), a wide-ranging selection of musical excerpts from Blind Willie Johnson to honkyoku, technical drawings and images of people from around the world, including Saan Hunters, city traffic and a nursing mother and child.
Since we still have not detected any alien life, we cannot know to what degree the records would be properly interpreted. Researchers still debate what forms such messages should take. For instance, should they include a star map identifying Earth? Should we focus on ourselves, or all life on Earth? Should we present ourselves as we are, or as comics artist Jack Kirby would have had it, as “the exuberant, self-confident super visions with which we’ve clothed ourselves since time immemorial”?
But the records serve a broader purpose than spreading the word that we’re here on our blue marble. After all, given the vast distances between the stars, it’s not realistic to expect an answer to these messages within many human lifetimes. So why send them and does their content even matter? Referring to earlier, similar efforts with the Pioneer spacecraft, Carl Sagan wrote, “the greater significance of the Pioneer 10 plaque is not as a message to out there; it is as a message to back here.” The real audience of these kinds of messages is not ET, but humanity.
In this light, 40 years’ hindsight shows the experiment to be quite a success, as they continue to inspire research and reflection.
Only two years after the launch of these messages to the stars, “Star Trek: The Motion Picture” imagined the success of similar efforts by (the fictional) Voyager VI. Since then, there have been Ph.D. theses written on the records’ content, investigations into the identity of the person heard laughing and successful crowdfunded efforts to reissue the records themselves for home playback.
The choice to include music has inspired introspection on the nature of music as a human endeavor, and what it would (or even could) mean to an alien species. If an ET even has ears, it’s still far from clear whether it would or could appreciate rhythm, tones, vocal inflection, verbal language or even art of any kind. As music scholars Nelson and Polansky put it, “By imagining an Other listening, we reflect back upon ourselves, and open our selves and cultures to new musics and understandings, other possibilities, different worlds.”
The records also represent humanity’s deliberate effort to put artifacts among the stars. Unlike everything on Earth, which is subject to erosion and all but inevitable destruction (from the sun’s eventual demise, if nothing else), the Golden Records are essentially eternal, a permanent time capsule of humanity. And unlike the Voyager spacecraft themselves – which were designed to have finite lifespans and whose journey into interstellar space was incidental to their primary function of exploring the outer planets – the Golden Records’ only purpose is to serve as ambassadors of humanity to the stars.
Placing artifacts in interstellar space thus makes the galaxy subject to the social studies, in addition to astronomy. The Golden Records mark our claim to interstellar space as part of our cultural landscape and heritage, and once the Voyager spacecraft themselves are not functional any longer, they will become proper achaeological objects. They are, in a sense, how we as a species have planted our flag of exploration in space. Anthropologist Michael Oman-Reagan muses, “Has NASA been to interstellar space because this spacecraft has? Have we, as a human species, [now] been to interstellar space?”
I would argue we have, and we are a better species for it. Like the Pioneer plaques and the Arecibo Message before them, the Golden Records inspire us to broaden our minds about what it means to be human; what we value as humans; and about our place and role in the cosmos by having us imagine what we might, or might not, have in common with any alien species our Voyagers eventually encounter on their very long journeys.
NASA Watches the Sun Put a Stop to Its Own Eruption On Sept. 30, 2014, multiple NASA observatories watched what appeared to be the beginnings of a solar eruption. A filament — a serpentine structure consisting of dense solar material and often associated with solar […]
TRAPPIST-1 is Older Than Our Solar System If we want to know more about whether life could survive on a planet outside our solar system, it’s important to know the age of its star. Young stars have frequent releases of high-energy radiation called flares that […]
Watch Martian Clouds Scoot, Thanks to NASA’s Curiosity
Wispy, early-season clouds resembling Earth’s ice-crystal cirrus clouds move across the Martian sky in some new image sequences from NASA’s Curiosity Mars rover.
These clouds are the most clearly visible so far from Curiosity, which landed five years ago this month about five degrees south of Mars’ equator. Clouds moving in the Martian sky have been observed previously by Curiosity and other missions on the surface of Mars, including NASA’s Phoenix Mars Lander in the Martian arctic nine years ago.
Researchers used Curiosity’s Navigation Camera (Navcam) to take two sets of eight images of the sky on an early Martian morning last month. For one set, the camera pointed nearly straight up. For the other, it pointed just above the southern horizon. Cloud movement was recorded in both and was made easier to see by image enhancement. A midday look at the sky with the same camera the same day showed no clouds.
Mars’ elliptical orbit makes that planet’s distance from the Sun vary more than Earth’s does. In previous Martian years, a belt of clouds has appeared near the equator around the time Mars was at its farthest from the Sun. The new images of clouds were taken about two months before that farthest point in the orbit, relatively early in the season for the appearance of this cloud belt.
“It is likely that the clouds are composed of crystals of water ice that condense out onto dust grains where it is cold in the atmosphere,” said Curiosity science-team member John Moores of York University, Toronto, Canada. “The wisps are created as those crystals fall and evaporate in patterns known as ‘fall streaks’ or ‘mare’s tails.’ While the rover does not have a way to ascertain the altitude of these clouds, on Earth such clouds form at high altitude.”
York’s Charissa Campbell produced the enhanced-image sequences by generating an “average” of all the frames in each sequence, then subtracting that average from each frame, emphasizing any frame-to-frame changes. The moving clouds are also visible, though fainter, in a sequence of raw images.
The Curiosity mission has been investigating the environmental conditions of ancient and modern Mars since the rover landed on Aug. 5, 2012, PDT (Aug. 6, EDT and Universal Time).
Provided by: Jet Propulsion Laboratory
The sun’s core rotates four times faster than its surface – here’s why it matters The sun by the Atmospheric Imaging Assembly of NASA’s Solar Dynamics Observatory. NASA/SDO (AIA) Stephen Serjeant, The Open University My favourite science news is the stuff that changes the way […]
Hint of Relativity Effects in Stars Orbiting Supermassive Black Hole at Centre of Galaxy A new analysis of data from ESO’s Very Large Telescope and other telescopes suggests that the orbits of stars around the supermassive black hole at the centre of the Milky Way […]
Cassini to Begin Final Five Orbits Around Saturn
NASA’s Cassini spacecraft will enter new territory in its final mission phase, the Grand Finale, as it prepares to embark on a set of ultra-close passes through Saturn’s upper atmosphere with its final five orbits around the planet.
Cassini will make the first of these five passes over Saturn at 12:22 a.m. EDT Monday, Aug. 14. The spacecraft’s point of closest approach to Saturn during these passes will be between about 1,010 and 1,060 miles (1,630 and 1,710 kilometers) above Saturn’s cloud tops.
The spacecraft is expected to encounter atmosphere dense enough to require the use of its small rocket thrusters to maintain stability – conditions similar to those encountered during many of Cassini’s close flybys of Saturn’s moon Titan, which has its own dense atmosphere.
“Cassini’s Titan flybys prepared us for these rapid passes through Saturn’s upper atmosphere,” said Earl Maize, Cassini project manager at NASA’s Jet Propulsion Laboratory (JPL) in California. “Thanks to our past experience, the team is confident that we understand how the spacecraft will behave at the atmospheric densities our models predict.”
Maize said the team will consider the Aug. 14 pass nominal if the thrusters operate between 10 and 60 percent of their capability. If the thrusters are forced to work harder – meaning the atmosphere is denser than models predict – engineers will increase the altitude of subsequent orbits. Referred to as a “pop-up maneuver,” thrusters will be used to raise the altitude of closest approach on the next passes, likely by about 120 miles (200 kilometers).
If the pop-up maneuver is not needed, and the atmosphere is less dense than expected during the first three passes, engineers may alternately use the “pop-down” option to lower the closest approach altitude of the last two orbits, also likely by about 120 miles (200 kilometers). Doing so would enable Cassini’s science instruments, especially the ion and neutral mass spectrometer (INMS), to obtain data on the atmosphere even closer to the planet’s cloud tops.
“As it makes these five dips into Saturn, followed by its final plunge, Cassini will become the first Saturn atmospheric probe,” said Linda Spilker, Cassini project scientist at JPL. “It’s long been a goal in planetary exploration to send a dedicated probe into the atmosphere of Saturn, and we’re laying the groundwork for future exploration with this first foray.”
Other Cassini instruments will make detailed, high-resolution observations of Saturn’s auroras, temperature, and the vortexes at the planet’s poles. Its radar will peer deep into the atmosphere to reveal small-scale features as fine as 16 miles (25 kilometers) wide – nearly 100 times smaller than the spacecraft could observe prior to the Grand Finale.
On Sept. 11, a distant encounter with Titan will serve as a gravitational version of a large pop-down maneuver, slowing Cassini’s orbit around Saturn and bending its path slightly to send the spacecraft toward its Sept. 15 plunge into the planet.
During the half-orbit plunge, the plan is to have seven Cassini science instruments, including INMS, turned on and reporting measurements in near real time. The spacecraft is expected to reach an altitude where atmospheric density is about twice what it encountered during its final five passes. Once Cassini reaches that point, its thrusters will no longer be able to work against the push of Saturn’s atmosphere to keep the spacecraft’s antenna pointed toward Earth, and contact will permanently be lost. The spacecraft will break up like a meteor moments later, ending its long and rewarding journey.
Provided by: JPL
How eclipses were regarded as omens in the ancient world A solar eclipse observed over Grand Canyon National Park in May 2012. Grand Canyon National Park Gonzalo Rubio, Pennsylvania State University On Monday, August 21, people living in the continental United States will be able […]