Most of our regular readers understand why astronauts and objects appear to float around on the International Space Station, but there are some misconceptions and preconceived notions out there on this topic that aren’t true and which don’t represent a very good understanding of physics! This video provides an entertaining look at some of the ideas people have about the zero-gravity environment on board an orbiting spacecraft, and shows why the astronauts actually appear weightless.
The latest installment of the excellent Symphony of Science series is out, and like every one of them it’s a fun, inspirational and educational trip through the cosmos with voiceovers by leading astronomers and physicists. These are great, and if you haven’t seen the others be sure to check them out on creator John Boswell’s YouTube channel here.
What fun! The science officer aboard the International Space Station, Don Pettit, does some simple but amazing science in his series, Science Off the Sphere. In his latest video, Pettit allows us to ‘see’ sound waves in space.
“I’m amazed at how much fun you can with something as simple as a set of speakers from your laptop computer and a splash of water,” said Pettit who added that he wanted to see how sound waves would affect water droplets “without the complications of gravity.”
Make sure you watch to the very end to rock out with Pettit and see the variations between the woofer and tweeter on the speaker and how the different sounds affect the water drops.
This artist's illustration gives an impression of how common planets are around the stars in the Milky Way. Credit: NASA, ESA, and M. Kornmesser (ESO)
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For many of us who grew up listening to Carl Sagan, watching robotic spacecraft travel to other worlds, and indulging in science fiction books and movies, it’s a given: one day we’ll find life somewhere else in the solar system or Universe. But are we being too optimistic? Two researchers say that our hopes and expectations of finding ET might be based more on optimism than scientific evidence, and the recent discoveries of exoplanets that might be similar to Earth are probably getting everyone’s hopes up too high.
Astrophysicist Edwin Turner from Princeton and researcher David Spiegel from the Institute for Advanced Study say the idea that life has or could arise in an another Earth-like environment has only a small amount of supporting evidence, most of it extrapolated from what is known about abiogenesis, or the emergence of life, on early Earth. Their research says the expectations of life cropping up on exoplanets are largely based on the assumption that it would or will happen if the same conditions as Earth exist elsewhere.
Using a Bayesian analysis — which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist — the duo concluded that current knowledge about life on other planets suggests Earth might be a cosmic aberration, where life took shape unusually fast and furious. If so, then the chances of the average terrestrial planet hosting life would be low.
“Fossil evidence suggests that life began very early in Earth’s history and that has led people to determine that life might be quite common in the universe because it happened so quickly here, but the knowledge about life on Earth simply doesn’t reveal much about the actual probability of life on other planets,” Turner said.
So, if a scientist starts out assuming that the chances of life existing on another planet is as large as on Earth, then their scientific results will be presented in a way that supports that likelihood, Turner said.
“Information about that probability comes largely from the assumptions scientists have going in, and some of the most optimistic conclusions have been based almost entirely on those assumptions,” he said.
Therefore, with all the exoplanets being found, and as our discoveries have become more and more enticingly Earth-like, these planets have our knowledge of life on Earth projected onto them, the researchers said.
How does an exoplanet researcher feel about this? Turner and Spiegel found a sympathetic soul in Joshua Winn from the Massachusetts Institute of Technology, who said that the two cast convincing doubt on a prominent basis for expecting extraterrestrial life.
“There is a commonly heard argument that life must be common or else it would not have arisen so quickly after the surface of the Earth cooled,” Winn said. “This argument seems persuasive on its face, but Spiegel and Turner have shown it doesn’t stand up to a rigorous statistical examination — with a sample of only one life-bearing planet, one cannot even get a ballpark estimate of the abundance of life in the universe.
It is true that science is about facts — not about what your gut feelings are. But there’s a strong argument that we need inspiration to do the best, most engaging science. Writer Andrew Zimmerman Jones blogged today at PBS about how many scientists were spurred to follow their careers by reading science fiction when they were young.
“The finest science fiction is inspired by the same thing that has inspired the greatest science discoveries throughout the ages: optimism for the future,” wrote Jones.
And perhaps that is what is mostly behind our hopes for finding ET: optimism for the future of the human race, that we really could one day travel to other worlds, and find new friends — “to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no one has gone before…”
Turner and Spiegel do say they are not making judgments, but just analyzing existing data that suggests the debate about the existence of life on other planets is framed largely by the prior assumptions of the participants.
“It could easily be that life came about on Earth one way, but came about on other planets in other ways, if it came about at all,” Turner said. “The best way to find out, of course, is to look. But I don’t think we’ll know by debating the process of how life came about on Earth.”
Video Caption: This mesmerizing video unveils incredibly amazing sequences around Jupiter and Saturn from NASA’s Cassini and Voyager missions set to stirring music by “The Cinematic Orchestra -That Home (Instrumental)”. Credit: Sander van den Berg
Don’t hesitate 1 moment ! Look and listen to this mind blowing video of the Jupiter and Saturnian systems.
Discovery and Enterprise rest nose-to-nose at ceremony transferring ownership of Discovery from NASA to the Smithsonian National Air & Space Museum on April 19, 2012. The official deed transfer ceremony took place at the Steven F. Udvar-Hazy Center in Chantilly, Virginia. Credit: Ken Kremer
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Space Shuttle Discovery, the longest serving and most flown spaceship in human history, entered her eternal home today, Thursday, April 19, at the Smithsonian’s National Air & Space Museum Annex in Virginia.
Discovery thereby assumed her new status as a museum relic and monument to the promise and glorious dreams of space exploration, inspiring future generations of explorers to reach far beyond their grasp and accomplish the unthinkable. That’s what space and science are all about.
The space shuttle program and all three of NASA’s winged spaceships were forcibly retired by politicians at the conclusion of the final shuttle mission, STS-135, in July 2011 which left America with no means to launch our own astronauts into space and to the International Space Station.
Shuttle astronauts march with Discovery being towed from Dulles to the Smithsonian’s Udvar Hazy Center on April 19, 2012. Credit: Ken Kremer
Discovery officially became the property of the Smithsonian Museum when NASA Administrator Charles Bolden signed the title of ownership over from NASA to the world renowned museum at a public ceremony held today at the Smithsonian’s Steven F. Udvar-Hazy Center in Chantilly, Virginia.
“Today, while we look back at Discovery’s amazing legacy, I also want to look forward to what she and the shuttle fleet helped to make possible,” said NASA Administrator Charles Bolden. “As NASA transfers the shuttle orbiters to museums across the country, we are embarked on an exciting new space exploration journey. Relying on American ingenuity and know-how, NASA is partnering with private industry to provide crew and cargo transportation to the International Space Station, while developing the most powerful rocket ever built to take the nation farther than ever before into the solar system.”
National Air and Space Museum Director, General John “Jack” Dailey said, “Discovery has distinguished itself as the champion of America’s shuttle fleet. In its new home, it will shine as an American icon, educating and inspiring people of all ages for generations to come. The Museum is committed to teaching and inspiring youngsters, so that they will climb the ladder of academic success and choose professions that will help America be competitive and successful in the world of tomorrow.”
Bolden and Dailey signed the transfer documents in front of the huge crowd who came to celebrate Discovery’s arrival.
Shuttle astronauts march with Discovery being towed from Dulles to the Smithsonian’s Udvar Hazy Center on April 19, 2012. Credit: Ken Kremer
The official handover ceremony was witnessed by a prestigious gathering of some three dozen astronauts including more than a dozen men and women who served as Commanders of Space Shuttle Discovery and Senator and Astronaut John Glenn, the first American to orbit the Earth 50 years ago in 1962.
Glenn flew to space for the 2nd time aboard Discovery as a payload specialist in 1998 at the age of 77. He is the oldest person to fly in space.
Shuttle astronauts march with Discovery being towed to the Smithsonian’s Udvar-Hazy Center and official Welcome ceremony on April 19, 2012. Credit: Ken Kremer
And the general public showed their enthusiastic support for NASA and space exploration by attending in the thousands and staying all day for the dozens of activity stations, presentations and displays organized by NASA and the Smithsonian and its donors.
Glenn made clear his disagreement with the end of NASA’s shuttle program.
Discovery arrives at her final resting place in the Smithsonian on April 19, 2012. Credit: Ken Kremer
To make way for Discovery, Space Shuttle Enterprise was first towed out a huge rear door of the museum early this morning. Discovery and Enterprise then met nose to nose as the dramatic backdrop for the official welcoming ceremony.
Late this afternoon, Discovery was towed to her final resting place into the museum to the exact spot formerly held by Enterprise, which had been on display at the Virginia facility since 2003.
Altogether, Discovery flew 39 missions and spent a full year (365 days) in space, orbited Earth 5,830 times and traveled 148,221,675 miles during a space flight career spanning 27 years.
Discovery flew its maiden voyage on Aug. 30, 1984 and blasted off on her final voyage on Feb. 24, 2011. The STS-133 mission was the final flight for the illustrious orbiter which landed at the Kennedy Space Center on March 9, 2012.
Discovery deployed the iconic Hubble Space Telescope to orbit, one of the premier science instruments built by humankind. Discovery delivered many other science payloads to orbit and also to explore the solar system, including the Ulysses solar probe.
The winged spaceship was NASA’s fleet leading orbiter and played a significant role in building the International Space Station and visiting the Russian Mir Space Station.
The Apollo Light Flash Moving Emulsion Detector (ALFMED), an experiment to record of incidents cosmic ray particles hitting astronauts. Credit: NASA
Astronauts have long reported the experience of seeing flashes while they are in space, even when their eyes are closed. Neil Armstrong and Buzz Aldrin both reported these flashes during the Apollo 11 mission, and similar reports during the Apollo 12 and 13 missions led to subsequent Apollo missions including experiments specifically looking at this strange phenomenon. These experiments involved blindfolding crewmembers and recording their comments during designated observation sessions, and later missions had a special device, the Apollo Light Flash Moving Emulsion Detector (ALFMED), which was worn by the astronauts during dark periods to record of incidents of cosmic ray hits.
It was determined the astronauts were ‘seeing’ cosmic rays zipping through their eyeballs. Cosmic rays are high-energy charged subatomic particles whose origins are not yet known. Fortunately, cosmic rays passing through Earth are usually absorbed by our atmosphere. But astronauts outside the atmosphere can find themselves “seeing things that aren’t there,” wrote current International Space Station astronaut Don Pettit, who told about his experience of seeing these flashes on his blog:
“In space I see things that are not there. Flashes in my eyes, like luminous dancing fairies, give a subtle display of light that is easy to overlook when I’m consumed by normal tasks. But in the dark confines of my sleep station, with the droopy eyelids of pending sleep, I see the flashing fairies. As I drift off, I wonder how many can dance on the head of an orbital pin.”
In a report on the Apollo experiment, astronauts described the types of flashes they saw in three ways: the ‘spot’, the ‘streak’, and the ‘cloud’; and all but one described the flashes as ‘white’ or ‘colorless.’ One crewmember, Apollo 15 Commander David Scott, described one flash as “blue with a white cast, like a blue diamond.”
Pettit described the physics/biology of what takes place:
“When a cosmic ray happens to pass through the retina it causes the rods and cones to fire, and you perceive a flash of light that is really not there. The triggered cells are localized around the spot where the cosmic ray passes, so the flash has some structure. A perpendicular ray appears as a fuzzy dot. A ray at an angle appears as a segmented line. Sometimes the tracks have side branches, giving the impression of an electric spark. The retina functions as a miniature Wilson cloud chamber where the recording of a cosmic ray is displayed by a trail left in its wake.”
Pettit said that the rate or frequency at which these flashes are seen varies with orbital position.
“There is a radiation hot spot in orbit, a place where the flux of cosmic rays is 10 to 100 times greater than the rest of the orbital path. Situated southeast of Argentina, this region (called the South Atlantic Anomaly) extends about halfway across the Atlantic Ocean. As we pass through this region, eye flashes will increase from one or two every 10 minutes to several per minute.
A cosmic ray hit on a camera appears as a segmented line in the image. Credit: NASA/Don Pettit..
During the Apollo missions, astronauts saw these flashes after their eyes had become dark-adapted. When it was dark, they reported a flash every 2.9 minutes on average. Only one Apollo crewmember involved in the experiments did not report seeing the phenomenon, Apollo 16’s Command Module Pilot Ken Mattingly, who stated that he had poor night vision.
These cosmic rays don’t just hit people, but things in space, too, and sometimes cause problems. Pettit wrote:
“Free from the protection offered by the atmosphere, cosmic rays bombard us within Space Station, penetrating the hull almost as if it was not there. They zap everything inside, causing such mischief as locking up our laptop computers and knocking pixels out of whack in our cameras. The computers recover with a reboot; the cameras suffer permanent damage. After about a year, the images they produce look like they are covered with electronic snow. Cosmic rays contribute most of the radiation dose received by Space Station crews. We have defined lifetime limits, after which you fly a desk for the rest of your career. No one has reached that dose level yet.”
The Phantom Torso experiment, AKA, Fred. Credit: NASA
There are experiments on board the ISS to monitor how much radiation the crew is receiving. One experiment is the Phantom Torso, a mummy-looking mock-up of the human body which determines the distribution of radiation doses inside the human body at various tissues and organs.
There’s also the Alpha Magnetic Spectrometer experiment, a particle physics experiment module that is mounted on the ISS. It is designed to search for various types of unusual matter by measuring cosmic rays, and hopefully will also tell us more about the origins of both those crazy flashes seen in space, and also the origins of the Universe.
I for one welcome our alien dinosaur overlords…maybe.
Dinosaurs once roamed and ruled the Earth. Is it possible that similar humongous creatures may have evolved on another planet – a world that DIDN’T get smacked by an asteroid – and later they developed to have human-like, intelligent brains? A recent paper discussing why the biochemical signature of life on Earth is so consistent in orientation somehow segued into the possibility that advanced versions of T. Rex and other dinosaurs may be the life forms that live on other worlds. The conclusion? “We would be better off not meeting them,” said scientist Ronald Breslow, author of the paper.
The building blocks of terrestrial amino acids, sugars, and the genetic materials DNA and RNA have two possible orientations, left or right, which mirror each other in what is called chirality. On Earth, with the exception of a few bacteria, amino acids have the left-handed orientation. Most sugars have a right-handed orientation. How did that homochirality happen?
If meteorites carried specific types of amino acids to Earth about 4 billion years, that could have set the pattern the left-handed chirality in terrestial proteins.
“Of course,” Breslow said in a press release, “showing that it could have happened this way is not the same as showing that it did. An implication from this work is that elsewhere in the universe there could be life forms based on D-amino acids and L-sugars. Such life forms could well be advanced versions of dinosaurs, if mammals did not have the good fortune to have the dinosaurs wiped out by an asteroidal collision, as on Earth.”
But not everyone was impressed with the notion of dinosaurs from space. “None of this has anything to do with dinosaurs,” wrote science author Brian Switek in the Smithsonian blog Dinosaur Tracking. “As much as I’m charmed by the idea of alien dinosaurs, Breslow’s conjecture makes my brain ache. Our planet’s fossil record has intricately detailed the fact that evolution is not a linear march of progress from one predestined waypoint to another. Dinosaurs were never destined to be. The history of life on earth has been greatly influenced by chance and contingency, and dinosaurs are a perfect example of this fact.”
A group of 49 former NASA employees from Johnson Space Center have written a letter to NASA Administrator Charlie Bolden, requesting that the space agency refrain from “unproven and unsubstantiated remarks” regarding how human activities are causing global climate change.
“As former NASA employees, we feel that NASA’s advocacy of an extreme position … is inappropriate,” says the letter. “We believe the claims by NASA and GISS(Goddard Institute for Space Studies) that man-made carbon dioxide is having a catastrophic impact on global climate change are not substantiated.”
The letter was reportedly supported by Leighton Steward from the Heartland Institute, an organization known for its stance of trying to cast doubt on global warming science.
“NASA has always been about looking out to the skies and beyond, not burying our heads in the sand,” climate scientist Michael Mann told Universe Today in an email “This is an old ploy, trying to cobble together a small group of individuals and make it sound like they speak with authority on a matter that they have really not studied closely. In this case, the effort was led by a fossil fuel industry-funded (climate change) denier who works for the Heartland Institute, and sadly he managed to manipulate this group of former NASA employees into signing on to this misguided statement.”
Mann added that 49 people out of tens of thousands of former and current NASA employees is just a tiny fraction, and that “NASA’s official stance, which represents the full current 16,000 NASA scientists and employees, is clear if you go to their website or look at their official publications: human-caused climate change is real, and it represents a challenge we must confront.”
NASA has responded to the letter, inviting those who signed it – which includes Apollo astronauts, engineers and former JSC officials – to join the debate in peer-reviewed scientific literature and public forums.
“NASA sponsors research into many areas of cutting-edge scientific inquiry, including the relationship between carbon dioxide and climate,” wrote Waleed Abdalati, NASA Chief Scientist. “As an agency, NASA does not draw conclusions and issue ‘claims’ about research findings. We support open scientific inquiry and discussion.”
“If the authors of this letter disagree with specific scientific conclusions made public by NASA scientists, we encourage them to join the debate in the scientific literature or public forums rather than restrict any discourse,” Abdalati concluded.
As several different people have noted — including former astronaut Rusty Schweickart who was quoted in the New York Times — most of those who signed the letter are not active research scientists and do not hold degrees in atmospheric sciences or fields related to climate change.
Schweickart, who was not among those who signed the letter, said in the New York Times that those who wrote the letter “have every right to state and argue for their opinion,” and climate scientist Gavin Schmidt added in the article that people stating their views is completely legitimate, “but they are asking the NASA administrator to censor other peoples’ (which is something else entirely).”
The letter from the former NASA employees – including Apollo astronauts Jack Schmitt, Walt Cunningham, Al Worden, and Dick Gordon — chides that since “hundreds of well-known climate scientists and tens of thousands of other scientists publicly declaring their disbelief in the catastrophic forecasts, coming particularly from the GISS leadership, it is clear that the science is NOT settled.”
Schmidt wrote previously on the RealClimate website that he certainly agrees the science is not settled. “No scientists would be scientists if they thought there was nothing left to find out…The reason why no scientist has said this (that the science is settled) is because they know full well that knowledge about science is not binary – science isn’t either settled or not settled. This is a false and misleading dichotomy.”
However, he added, “In the climate field, there are a number of issues which are no longer subject to fundamental debate in the community. The existence of the greenhouse effect, the increase in CO2 (and other GHGs) over the last hundred years and its human cause, and the fact the planet warmed significantly over the 20th Century are not much in doubt.”
