Artist's impression of The Milky Way Galaxy. Based on current estimates and exoplanet data, it is believed that there could be tens of billions of habitable planets out there. Credit: NASA
Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that the reason we’ve found no evidence of alien civilizations is because there are none out there.
It’s become a legend of the space age. The brilliant physicist Enrico Fermi, during a lunchtime conversation at Los Alamos National Laboratory in 1950, is supposed to have posed a conundrum for proponents of the existence of extraterrestrial civilizations.
If space traveling aliens exist, so the argument goes, they would spread through the galaxy, colonizing every habitable world. They should then have colonized Earth. They should be here, but because they aren’t, they must not exist.
This is the argument that has come to be known as “Fermi’s paradox”. The problem is, as we saw in the first installment, Fermi never made it. As his surviving lunch companions recall (Fermi himself died of cancer just four years later, and never published anything on the topic of extraterrestrial intelligence), he simply raised a question, “Where is everybody?” to which there are many possible answers.
These six narrow-angle color images were made from the first ever "portrait" of the solar system taken by Voyager 1 on Valentine’s Day on Feb. 14, 1990, which was more than 4 billion miles from Earth and about 32 degrees above the ecliptic. Venus, Earth, Jupiter, and Saturn, Uranus, Neptune are seen in these blown-up images, from left to right and top to bottom. Credit: NASA/JPL-Caltech
A quarter of a century has passed since NASA’s Voyager 1 spacecraft snapped the iconic image of Earth known as the “Pale Blue Dot” that shows all of humanity as merely a tiny point of light.
The outward bound Voyager 1 space probe took the ‘pale blue dot’ image of Earth 25 years ago on Valentine’s Day, on Feb. 14, 1990 when it looked back from its unique perch beyond the orbit of Neptune to capture the first ever “portrait” of the solar system from its outer realms.
Voyager 1 was 4 billion miles from Earth, 40 astronomical units (AU) from the sun and about 32 degrees above the ecliptic at that moment.
The idea for the images came from the world famous astronomer Carl Sagan, who was a member of the Voyager imaging team at the time.
He head the idea of pointing the spacecraft back toward its home for a last look as a way to inspire humanity. And to do so before the imaging system was shut down permanently thereafter to repurpose the computer controlling it, save on energy consumption and extend the probes lifetime, because it was so far away from any celestial objects.
Sagan later published a well known and regarded book in 1994 titled “Pale Blue Dot,” that refers to the image of Earth in Voyagers series.
This narrow-angle color image of the Earth, dubbed “Pale Blue Dot,” is a part of the first ever “portrait” of the solar system taken by Voyager 1 on Valentine’s Day on Feb. 14, 1990. Credit: NASA/JPL-Caltech
“Twenty-five years ago, Voyager 1 looked back toward Earth and saw a ‘pale blue dot,’ ” an image that continues to inspire wonderment about the spot we call home,” said Ed Stone, project scientist for the Voyager mission, based at the California Institute of Technology, Pasadena, in a statement.
Six of the Solar System’s nine known planets at the time were imaged, including Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. The other three didn’t make it in. Mercury was too close to the sun, Mars had too little sunlight and little Pluto was too dim.
Voyager snapped a series of images with its wide angle and narrow angle cameras. Altogether 60 images from the wide angle camera were compiled into the first “solar system mosaic.”
Voyager 1 was launched in 1977 from Cape Canaveral Air Force Station in Florida as part of a twin probe series with Voyager 2. They successfully conducted up close flyby observations of the gas giant outer planets including Jupiter, Saturn, Uranus and Neptune in the 1970s and 1980s.
Both probes still operate today as part of the Voyager Interstellar Mission.
“After taking these images in 1990, we began our interstellar mission. We had no idea how long the spacecraft would last,” Stone said.
Hurtling along at a distance of 130 astronomical units from the sun, Voyager 1 is the farthest human-made object from Earth.
Solar System Portrait – 60 Frame Mosaic. The cameras of Voyager 1 on Feb. 14, 1990, pointed back toward the sun and took a series of pictures of the sun and the planets, making the first ever “portrait” of our solar system as seen from the outside. Missing are Mercury, Mars and Pluto. Credit: NASA/JPL-Caltech
Voyager 1 still operates today as the first human made instrument to reach interstellar space and continues to forge new frontiers outwards to the unexplored cosmos where no human or robotic emissary as gone before.
Here’s what Sagan wrote in his “Pale Blue Dot” book:
“That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. … There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
This Chandra image of the Tycho supernova remnant contains new evidence for what triggered the original supernova explosion. Credit: NASA/CXC/Chinese Academy of Sciences/F. Lu et al.
At one time or another, all science enthusiasts have heard the late Carl Sagan’s infamous words: “We are made of star stuff.” But what does that mean exactly? How could colossal balls of plasma, greedily burning away their nuclear fuel in faraway time and space, play any part in spawning the vast complexity of our Earthly world? How is it that “the nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies” could have been forged so offhandedly deep in the hearts of these massive stellar giants?
Unsurprisingly, the story is both elegant and profoundly awe-inspiring.
All stars come from humble beginnings: namely, a gigantic, rotating clump of gas and dust. Gravity drives the cloud to condense as it spins, swirling into an ever more tightly packed sphere of material. Eventually, the star-to-be becomes so dense and hot that molecules of hydrogen in its core collide and fuse into new molecules of helium. These nuclear reactions release powerful bursts of energy in the form of light. The gas shines brightly; a star is born.
The ultimate fate of our fledgling star depends on its mass. Smaller, lightweight stars burn though the hydrogen in their core more slowly than heavier stars, shining somewhat more dimly but living far longer lives. Over time, however, falling hydrogen levels at the center of the star cause fewer hydrogen fusion reactions; fewer hydrogen fusion reactions mean less energy, and therefore less outward pressure.
At a certain point, the star can no longer maintain the tension its core had been sustaining against the mass of its outer layers. Gravity tips the scale, and the outer layers begin to tumble inward on the core. But their collapse heats things up, increasing the core pressure and reversing the process once again. A new hydrogen burning shell is created just outside the core, reestablishing a buffer against the gravity of the star’s surface layers.
While the core continues conducting lower-energy helium fusion reactions, the force of the new hydrogen burning shell pushes on the star’s exterior, causing the outer layers to swell more and more. The star expands and cools into a red giant. Its outer layers will ultimately escape the pull of gravity altogether, floating off into space and leaving behind a small, dead core – a white dwarf.
Lower-mass stars like our sun eventually enter a swollen, red giant phase. Ultimately, its outer layers will be thrown off altogether, leaving nothing but a small white dwarf star. Image Credit: ESO/S. Steinhofel
Heavier stars also occasionally falter in the fight between pressure and gravity, creating new shells of atoms to fuse in the process; however, unlike smaller stars, their excess mass allows them to keep forming these layers. The result is a series of concentric spheres, each shell containing heavier elements than the one surrounding it. Hydrogen in the core gives rise to helium. Helium atoms fuse together to form carbon. Carbon combines with helium to create oxygen, which fuses into neon, then magnesium, then silicon… all the way across the periodic table to iron, where the chain ends. Such massive stars act like a furnace, driving these reactions by way of sheer available energy.
But this energy is a finite resource. Once the star’s core becomes a solid ball of iron, it can no longer fuse elements to create energy. As was the case for smaller stars, fewer energetic reactions in the core of heavyweight stars mean less outward pressure against the force of gravity. The outer layers of the star will then begin to collapse, hastening the pace of heavy element fusion and further reducing the amount of energy available to hold up those outer layers. Density increases exponentially in the shrinking core, jamming together protons and electrons so tightly that it becomes an entirely new entity: a neutron star.
At this point, the core cannot get any denser. The star’s massive outer shells – still tumbling inward and still chock-full of volatile elements – no longer have anywhere to go. They slam into the core like a speeding oil rig crashing into a brick wall, and erupt into a monstrous explosion: a supernova. The extraordinary energies generated during this blast finally allow the fusion of elements even heavier than iron, from cobalt all the way to uranium.
Periodic Table of Elements. Massive stars can fuse elements up to Iron (Fe), atomic number 26. Elements with atomic numbers 27 through 92 are produced in the aftermath of a massive star’s core collapse.
The energetic shock wave produced by the supernova moves out into the cosmos, disbursing heavy elements in its wake. These atoms can later be incorporated into planetary systems like our own. Given the right conditions – for instance, an appropriately stable star and a position within its Habitable Zone – these elements provide the building blocks for complex life.
Today, our everyday lives are made possible by these very atoms, forged long ago in the life and death throes of massive stars. Our ability to do anything at all – wake up from a deep sleep, enjoy a delicious meal, drive a car, write a sentence, add and subtract, solve a problem, call a friend, laugh, cry, sing, dance, run, jump, and play – is governed mostly by the behavior of tiny chains of hydrogen combined with heavier elements like carbon, nitrogen, oxygen, and phosphorus.
Other heavy elements are present in smaller quantities in the body, but are nonetheless just as vital to proper functioning. For instance, calcium, fluorine, magnesium, and silicon work alongside phosphorus to strengthen and grow our bones and teeth; ionized sodium, potassium, and chlorine play a vital role in maintaining the body’s fluid balance and electrical activity; and iron comprises the key portion of hemoglobin, the protein that equips our red blood cells with the ability to deliver the oxygen we inhale to the rest of our body.
So, the next time you are having a bad day, try this: close your eyes, take a deep breath, and contemplate the chain of events that connects your body and mind to a place billions of lightyears away, deep in the distant reaches of space and time. Recall that massive stars, many times larger than our sun, spent millions of years turning energy into matter, creating the atoms that make up every part of you, the Earth, and everyone you have ever known and loved.
We human beings are so small; and yet, the delicate dance of molecules made from this star stuff gives rise to a biology that enables us to ponder our wider Universe and how we came to exist at all. Carl Sagan himself explained it best: “Some part of our being knows this is where we came from. We long to return; and we can, because the cosmos is also within us. We’re made of star stuff. We are a way for the cosmos to know itself.”
“This is how we know nature. It is the best idea humans have ever come up with.”
– Bill Nye, Science Guy and CEO of The Planetary Society
In this latest video from NOVA’s Secret Life of Scientists and Engineers, science guy Bill Nye talks about the incredible influence that Carl Sagan had on his life, from attending his lectures on astronomy at Cornell University to eventually becoming CEO of The Planetary Society, which was co-founded by Sagan in 1980.
“I took astronomy from Carl Sagan.” Now there’s a statement that’ll get people’s attention. (It got mine, anyway.)
Dr. Neil deGrasse Tyson contemplates the Big Bang. Image courtesy of Fox.
With much anticipation from the astronomy and science community, the opening episode of the new and updated version of Carl Sagan’s “Cosmos” series premiered to the masses on television in North America last night. This reboot – this time hosted by astrophysicist Neil de Grasse Tyson — did a wonderful job of paying homage to Sagan while showcasing the grandeur of space, as well as portraying the infinitesimally small amount of time that humanity has existed. Like its original counterpart, the first episode of the series takes viewers on a quick tour of the Solar System and Universe, showing our cosmic “address” as it were, going back to the Big Bang, but also touching on multiverses and a potentially infinite Universe.
As de Grasse Tyson said at the beginning, “from the infinitesimal to the infinite; from the dawn of time to the distant future.”
There were also – seemingly – an infinite number of commercial interruptions. You can watch the episode in its entirety below, without commercials, thankfully. Watching it on television last night was disappointing because of those commercial interruptions – sometimes only a couple of minutes apart — making one wish for the PBS-commercial-free version of the original Cosmos with Sagan.
And I wasn’t the only one feeling those sentiments:
What I miss most from the original 'Cosmos'? No commercials #Cosmos
(Yes, I watched the show while keeping an eye on what the Twitterverse had to say about it.)
But airing the series on the Fox Network and its affiliated channels (I watched it on the National Geographic Channel) was a calculated move by the series’ producer Seth MacFarlane to showcase the series and the science to a population that may not otherwise be exposed to science at this “popular” level. And clearly, science and the scientific method gets top billing in this series:
“This adventure is made possible by generations of searchers strictly adhering to a general set of rules: test ideas by experiment and observation … follow the evidence where it leads and question everything,” said Tyson.
This planetary nebula’s simple, graceful appearance is thought to be due to perspective: our view from Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star. Hot blue gas near the energizing central star gives way to progressively cooler green and yellow gas at greater distances with the coolest red gas along the outer boundary. Credit: NASA/Hubble Heritage Team
With a combination of real images from telescopes and spacecraft, computer generated imagery and surprisingly watchable animations, most intriguing for me was the “cosmic calendar.” Those who have seen Sagan’s original series will remember his version of the cosmic calendar as a way to conceptualize the age of the Universe, compressing 13.9 billion years down to one year. Tyson’s flashier calendar also showed how January 1 would mark the Big Bang and December 31 would be the present – making each day represent about 40 million years. At this rate, humanity’s entire recorded history only occupies just the last 14 seconds of the year.
But as Tyson noted, science has provided unmatched discoveries during that short span of time: “The scientific method is so powerful that in a mere four centuries, it has taken us from Galileo’s’ first look through the telescope to knowing our place in the Universe.”
Giordano Bruno in Cosmos. Image courtesy of Fox.
When I heard there were going to be animated sequences of historical events (the original series used actor portrayals) I was disappointed, but the animations in this series premiere surprised me by being quite engaging.
They told the story of Giordano Bruno, the 16th century Italian monk turned astronomer. He had theorized that other planets existed with other lifeforms like ours. In his 1584 book “On the Infinite Universe and Worlds,” Bruno wrote : “… there is a single general space, a single vast immensity which we may freely call Void; in it are innumerable globes like this one on which we live and grow. This space we declare to be infinite… In it are an infinity of worlds of the same kind as our own.”
This was controversial for his time, but even in a church-dominated society, it wasn’t grounds for being declared a heretic. But later Bruno followed his argument to its logical conclusion: if there are an infinity of worlds, and if some worlds have sentient beings created by God, then wouldn’t these planets also need to be saved by God? The notion other Jesuses was not viewed well, and the church convicted him of heresy, and burned him at the stake.
Phil Plait talked more about this today in his review of “Cosmos” and I agree with him that this wasn’t really about showing religion in a bad light, but about making “a bigger point about suppression of thought and the grandeur of freedom of exploration of ideas.”
Other fun moments were when a CGI (but quite realistic) dinosaur fish named a Tiktaalik crawled out of the sea right next to Tyson, depicting the evolution of life on Earth. Most endearing was perhaps Tyson’s claim that “we are ALL descended from astronomers;” how our ancestors depended on the stars to know the change of seasons.
While this series premier was a quick overview, one surprise is that it showed just one theory – and the oldest and perhaps outdated — of how our Moon was formed, by a conglomeration of the same debris that make up Earth. These days it seems the theory of a Mars-sized planetary collision is the most accepted theory.
The show began and ended with the voice and words of Carl Sagan, and Tyson shared his story about his own personal interactions with Sagan. This was a very authentic part of the show, and allowed the torch to be passed from Sagan to Tyson.
If you missed it: Karma. "For Neil Tyson, With all good wishes to a future astronomer" – Carl Sagan pic.twitter.com/BQ2p6RRRys
And then there was Tyson using Sagan’s famous “we are made star stuff” quote:
“They get so hot that the nuclei of the atoms fuse together deep within them to make the oxygen with breathe, the carbon in our muscles, the calcium in our bones, the iron in our blood,” Tyson said. “You, me, everyone: We are made of star stuff.”
Astronomer thought process: RT @Alex_Parker: S?T?A?R? ?G?U?T?S?
S?T?A?R? ?R?E?F?U?S?E?
S?T?A?R? ?B?E?L?L?Y?B?U?T?T?O?N? ?L?I?N?T?
STAR STUFF
This series premiere was a rousing tribute to science and I am definitely looking forward to more. Here’s hoping this series does what MacFarlane had in mind: get the general public to start talking about science again.
If you are feeling the need for more “Cosmos” you can watch the original series at Hulu Plus, and at the Carl Sagan website, learn more about the legend.
Sunday is going to be a once-in-a-generation moment. For those of us who were too young to remember the original Cosmos (writer puts hand up) or those who are eager to see the classic 1980 Carl Sagan series updated with discoveries since then, we’re all in luck. A new series starring astronomer Neil deGrasse Tyson is premiering on Fox.
NASA hosted a sneak preview of the series at several NASA centers, and the early reviews on Twitter indicated a heck of a lot of excited people in the audience. In the video above, you can watch the Q&A with the main players after the premiere concluded.
“Watching Cosmos, I saw a Brooklyn-born researcher pull back the curtain on a world of seemingly dense scientific concepts, which, with the flair of P.T. Barnum, he managed to present in ways that made them accessible to those of us lacking a degree in mathematics or physics,” Seth MacFarlane, the executive producer of Cosmos (who is best known for creating Family Guy), said in a statement.
“He was able to make a discussion of the most distant stellar objects suddenly become relevant to our small, day-to-day lives. And he did so with such obvious passion, enthusiasm, and love for the knowledge he imparted that even those who had little interest in science found it impossible not to want to go along for the ride.”
The original Cosmos series premiered in 1980 and won three primetime Emmys. Sagan — who was involved in NASA missions such as the Voyagers — combined his worktime experiences with more meditative thoughts on the cosmos, the role of intelligence and the future of the universe. It’s still easy to purchase the original series, despite its age, so we’re sure Fox is hoping for the same kind of longevity with the reboot.
deGrasse Tyson, for those who don’t know, is the engaging director of the Hayden Planetarium in New York. Like Sagan, he’s a New York City-based popularizer of science who appears regularly on shows that aren’t necessarily science focused — such as The Colbert Report, where he has spoken several times and is often cited as one of Colbert’s most-returning guests, if not the most returning one.
We’ll be eagerly watching the series as it comes out. For more information, you can check out Fox’s website.
Credit: Inside Science News Service and Amanda Page
As the Beatles strummed the opening notes to “All My Loving” on the Ed Sullivan Show 50 years ago yesterday, few could have imagined how wide-ranging that music would be. The broadcast gave birth to a global music phenomenon. And like all TV broadcasts of the day, the music carried out into space at the speed of light.
The Inside Science infographic above (see below for the full version) traces the history of the Beatles in relation to how far the broadcast travelled in that time. While those waves were washing out, er, across the universe, the Beatles have been taking over human space exploration in other ways. Below the jump are seven of the more memorable moments.
Rocking The Space Station With ‘Back at the ISS’
Technically speaking, this isn’t the Beatles, but it sure was inspired by them. ‘Back at the ISS’ — the remake of ‘Back in the U.S.S.R.’ by Dutch band Love & Mersey — is about a billion shades of awesome. Not only because of the lyrics, not only because of the high-energy space-themed video, but also because they sang in three languages. The song was released in March 2012 as a “rocking musical greeting” to Andre Kuipers (a European Space Agency astronaut) and the rest of the Expedition 30 crew days before the docking of the Automated Transfer Vehicle Edoardo Amaldi that month.
The Beatles have been used to wake up several shuttle crews, and also the Curiosity rover. Explained Eric Blood, Curiosity’s surface systems engineer: “She tends to be less cranky with a good wakeup song.”
Playing (And Drinking?) English Tea In Space
Here’s Paul McCartney in 2005 casually playing two tunes to the Expedition 12 crew — NASA astronaut Bill McArthur and Russian cosmonaut Valery Tokarev — during a live concert. It’s a bit hard to tell who had bigger stars in their eyes after the experience. “I told the audience ‘I think I need about 20 minutes to go have a lie down,’ McCartney stated in a NASA release from the time. “What do you do after that? We haven’t stopped talking about it since.”
Roll Over Beethoven: How The Beatles Almost Made Voyager’s ‘Golden Record’
Remember when scientists announced last year that Voyager 1 entered interstellar space? On board the spacecraft was a Golden Record intended to give aliens a glimpse into what Earth’s life is like. Included were songs from artists ranging from Bach to Blind Willie Johnson, but not the Beatles. They were almost included, though, as astronomer Carl Sagan (who chaired the selection committee) explained in his 1978 book Murmers of Earth. “We wanted to send ‘Here Comes The Sun’ by the Beatles, and all four Beatles gave their approval. But the Beatles did not own the copyright, and the legal status of the piece seemed too murky to risk,” he wrote.
Joining Mr. Mercury’s Light
There are so many earthly memorials to John Lennon after the singer’s untimely death in 1980, but late last year he got an extraterrestrial honor. Lennon was among 10 names approved for craters on the planet Mercury. “It’s unlikely that Mercury’s surface is populated with tangerine trees and marmalade skies, but the famous British musician who coined that phrase now has a physical presence on the planet closest to the Sun,” NASA said.
Sending Love To The Aliens With Jai Guru Deva Om
February 4, 2008 marked the first time NASA beamed any song into deep space, and what better choice than “Across The Universe”? The date marked the 40th anniversary of when the Beatles recorded the song, and came around the same time as the 45th anniversary of NASA’s Deep Space Network and the 50th anniversary of NASA’s first satellite, Explorer 1, among other milestones. In a statement, McCartney asked to “send my love to the aliens.”
What Beatles milestones in space have we missed? Let us know in the comments.
Every now and then, someone takes Carl Sagan’s wonderful reading of his iconic “Pale Blue Dot” narrative and turns it into an animated presentation, usually combining images and video footage of space exploration and Earthly vistas to create something undeniably spellbinding (Sagan’s narratives do have a tendency to have that effect!) Artist Adam Winnik went a slightly different route, however, creating an illustrated animation to go along with Sagan’s reading for his thesis project in 2011. The result is no less poignant… check it out above.
Taking a break from reading Pale Blue Dot in Carl Sagan’s hometown of Ithaca, New York. (Elizabeth Howell)
I never knew of Carl Sagan as a living human being, as I missed him by mere months. I read Pale Blue Dot sometime in 1997, if my memory serves, sometime after the movie Contact (based on his book) came out in theaters and I asked my parents what the “FOR CARL” dedication was at the end of the movie.
At a time when I was all awkward teenagerhood, Sagan’s writing showed me a Universe of beauty. Not organized beauty, to be sure, but a destination worth exploring. Worth learning more about, even from a humble perch on Earth.
Sagan had a bit of everything in him: a knowledge of philosophy and history, an influence on early NASA missions, an ability to take the Universe and make it homey enough to show on television screens and in books.
His formative research years were at Cornell University in Ithaca, New York. More than 15 years after his death, he’s actually pretty easy to find in that town.
Carl Sagan’s grave in Lakeview Cemetery in Ithaca, New York, adorned with blue marbles. It’s between the two trees in this map. (Elizabeth Howell)
The exterior of the Space Sciences building at Cornell University, where Carl Sagan spent his most influential research years. (Elizabeth Howell)
Carl Sagan’s picture at the Sciencenter in Ithaca. He was a founding member of the science museum’s advisory board. (Elizabeth Howell)
Our Sun shining upon an exhibit of Neptune in Ithaca’s Planet Walk. The 1200-meter walk has the distances of all the planets in the solar system to scale. The exhibition was created in honor of Carl Sagan’s memory, and has a podcast available that is narrated by one of his students: Bill Nye, the Science Guy. (Elizabeth Howell)
Today would have been Carl Sagan’s 78th birthday, and the past few years November 9th, the anniversary of his birth, has been designated as “Carl Sagan Day” by people who appreciate Sagan’s influence — not only on science, but also the public’s understanding of it. Sagan passed away 16 years ago, but his words and inspiration live on for many of us through his books and recordings.
Sagan was a co-founder of The Planetary Society, and this evening (Friday, Nov. 9, 2012) at 7 pm PST TPS will be webcasting a live event to commemorate Sagan’s life and influence. Click here for the webcast link, as well as additional information.
Below is part one of a 3 part series of Sagan’s final interview with Charlie Rose on May 27, 1996. He discussed science, pseudo-science, religion, and his struggle with the disease that ultimately ended his life, myelodysplasia.
If you have a favorite Sagan quote or memory, feel free to share it in the comments.
