John Glenn: Godspeed and Rest in Peace

John Glenn always had the right stuff.

Glenn, the first American astronaut to orbit the Earth and a legendary figure around the world, has died. Glenn, 95, was the last remaining Mercury astronaut, the first group of US astronauts. He flew on Friendship 7 on Feb. 20, 1962, and later flew on the space shuttle in 1998 at age 77, becoming the oldest astronaut to fly in space. He also spent 24 years as a U.S. Senator from Ohio, and had a run for the presidency.

Astronaut John Glenn views stencilling used as a model to paint the words "Friendship 7" on his spacecraft. Credit: NASA
Astronaut John Glenn views stencilling used as a model to paint the words “Friendship 7” on his spacecraft. Credit: NASA

Glenn will always be remembered as the first American to orbit the Earth during those tentative, challenging, daring days when humans were just beginning to venture beyond the atmosphere that had nurtured them since the species began. – NASA obituary of John Glenn

“With John’s passing, our nation has lost an icon and Michelle and I have lost a friend,” said President Obama said in a statement. Obama added that Glenn’s flight pioneering flight “reminded us that with courage and a spirit of discovery there’s no limit to the heights we can reach together.”

“On behalf of a grateful nation, Godspeed, John Glenn.”

“John spent his life breaking barriers, from defending our freedom as a decorated Marine Corps fighter pilot in World War II and Korea, to setting a transcontinental speed record, to becoming, at age 77, the oldest human to touch the stars,” Obama said. “John always had the right stuff, inspiring generations of scientists, engineers and astronauts who will take us to Mars and beyond — not just to visit, but to stay.”

Glenn, born on July 18, 1921, was described in statement by his family and Trevor Brown, dean of the John Glenn School of Public Affairs at Ohio State University, as “humble, funny, and generous.” And “even after leaving public life, he loved to meet with citizens, school children in particular. He thrilled to music and had a weakness for chocolate.”

Glen married his childhood sweetheart, Annie Castor, and studied at Muskingum College in Ohio. Glenn became a Marine Corps fighter and flew 59 combat missions during World War II and 90 in the Korean War.

Glenn attended Test Pilot School at the Naval Air Test Center, Patuxent River, Md. After graduation, he was project officer on a number of aircraft. In July 1957, he set a transcontinental speed record from Los Angeles to New York — 3 hours and 23 minutes. It was the first transcontinental flight to average supersonic speed.

Glenn accumulated nearly 9,000 hours of flying time, about 3,000 of it in jets.

The ‘space race’ began when the Soviet Union launched the first satellite, Sputnik, in 1957. After a series of failures for the US space program, they finally succeeded on February 1, 1958 when Explorer 1 became the first US satellite in space.

But the main goal was to send humans to space.

The original seven astronauts pose with an Atlas model July 12, 1962. The "en:Mercury Seven" astronauts pose with an Atlas model on July 12, 1962. Front row, left to right: Gus Grissom, Scott Carpenter, Deke Slayton and Gordon Cooper. Back row: Alan Shepard, Wally Schirra and John Glenn. Credit: NASA
The original seven astronauts pose with an Atlas model July 12, 1962. The ‘Mercury Seven’ astronauts pose with an Atlas model on July 12, 1962. Front row, left to right: Gus Grissom, Scott Carpenter, Deke Slayton and Gordon Cooper. Back row: Alan Shepard, Wally Schirra and John Glenn. Credit: NASA

In 1959, when the newly-formed National Aeronautics and Space Administration searched for the first Americans to fly in space, it focused on military test pilots. Glenn was in the select group – known as the Mercury 7 — who was chosen.

Glenn was assigned to the NASA Space Task Group at Langley, Va., in April 1959. The Space Task Group was moved to Houston and became part of the NASA Manned Spacecraft Center (which is now Johnson Space Center in Houston) in 1962.
While Glenn wasn’t chosen for the first Mercury space flight, his flight is well-remembered for being the first American to orbit Earth. But before any US astronauts could be launched into space, history was made on April 12, 1961 when Russian cosmonaut Yuri A. Gagarin became the first human in space when he completed his successful orbital flight aboard Vostok I.

Prior to Glenn’s 4-hour, 55-minute flight in Friendship 7, Glenn had served as backup pilot for astronauts Alan Shepard, the first American in space who flew on May 5, 1961, and to Virgil “Gus” Grissom, who followed Shepard on another suborbital flight on July 21, 1961.

On Feb. 20, 1962, Glenn launched from Cape Canaveral on Friendship 7, circling the earth three times. He became a national hero.

“Roger, liftoff, and the clock is running. We’re under way,” Glenn said after launch. After reaching space he said, “Zero-G and I feel fine. Man, that view is tremendous.”

Then-Senator Glenn joined the STS-95 Discovery crew in 1998, becoming the oldest person to fly in space at 77. Credit: NASA
Then-Senator Glenn joined the STS-95 Discovery crew in 1998, becoming the oldest person to fly in space at 77. Credit: NASA

Glenn was awarded the Presidential Medal of Freedom in 2012.

“The last of America’s first astronauts has left us, but propelled by their example we know that our future here on Earth compels us to keep reaching for the heavens,” Obama said.

Here are some tributes via Tweets for John Glenn:

Tutankhamun’s Meteorite Blade

The Egyptian Pyramids; instantly recognizable to almost anyone. Image: Armstrong White, CC BY 2.0

The spread of metallurgy in different civilizations is a keen point of interest for historians and archaeologists. It helps chart the rise and fall of different cultures. There are even names for the different ages corresponding to increasingly sophisticated metallurgical technologies: the Stone Age, the Bronze Age, and the Iron Age.

But sometimes, a piece of evidence surfaces that doesn’t fit our understanding of a civilization.

Probably the most iconic ancient civilization in all of history is ancient Egypt. Its pyramids are instantly recognizable to almost anyone. When King Tutankhamun’s almost intact tomb was discovered in 1922, it was a treasure trove of artifacts. And though the tomb, and King Tut, are most well-known for the golden death mask, it’s another, little-known artifact that has perhaps the most intriguing story: King Tut’s iron dagger.

King Tutankhamun's Golden Death Mask, one of the most stunning human artifacts in existence. Image: Carsten Frenzl, CC BY 2.0
King Tutankhamun’s Golden Death Mask, one of the most stunning human artifacts in existence. Image: Carsten Frenzl, CC BY 2.0

King Tut’s iron-bladed dagger wasn’t discovered until 1925, three years after the tomb was discovered. It was hidden in the wrappings surrounding Tut’s mummy. It’s mere existence was a puzzle, because King Tut reigned in 1332–1323 BC, 600 years before the Egyptians developed iron smelting technology.

King Tut's iron dagger was concealed in the wrappings surrounding the boy-king's mummy. Image: Daniela Comelli/Polytechnic University of Milan
King Tut’s iron dagger was concealed in the wrappings surrounding the boy-king’s mummy. Image: Daniela Comelli/Polytechnic University of Milan

It was long thought, but never proven, that the blade may be made of meteorite iron. In the past, tests have produced inconclusive results. But according to a new study led by Daniela Comelli, of the Polytechnic University of Milan, and published in the Journal of Meteoritics and Planetary Science, there is no doubt that a meteorite was the source of iron for the blade.

The team of scientists behind the study used a technique called x-ray fluorescence spectrometry to determine the chemical composition of the blade. This technique aims x-rays at an artifact, then determines its composition by the spectrum of colors given off. Those results were then compared with 11 other meteorites.

In the dagger’s case, the results indicated Fe plus 10.8 wt% Ni and 0.58 wt% Co. This couldn’t be a coincidence, since iron meteorites are mostly made of Fe (Iron) and Ni (Nickel), with minor quantities of Co (Cobalt), P (Phosphorus), S (Sulphur), and C (Carbon). Iron found in the Earth’s crust has almost no Ni content.

Testing of Egyptian artifacts is a tricky business. Egypt is highly protective of their archaeological resources. This study was possible only because of advances in portable x-ray fluorescence spectrometry, which meant the dagger didn’t have to be taken to a lab and could be tested at the Egyptian Museum of Cairo.

Iron objects were rare in Egypt at that time, and were considered more valuable than gold. They were mostly decorative, probably because ancient Egyptians found iron very difficult to work. It requires a very high heat to work with, which was not possible in ancient Egypt.

Iron meteorites like this one would have attracted the attention of ancient Egyptians. This one is the Bendego meteorite from Brazil. Image: Jorge Andrade - Flickr: National Museum, Rio de Janeiro CC BY 2.0
Iron meteorites like this one would have attracted the attention of ancient Egyptians. This one is the Bendego meteorite from Brazil. Image: Jorge Andrade – Flickr: National Museum, Rio de Janeiro CC BY 2.0

Even without the ability to heat and work iron, a great deal of craftsmanship went into the blade. The dagger itself had to be hammered into shape, and it features a decorated golden handle and a rounded rock crystal knob. It’s golden sheath is decorated with a jackal’s head and a pattern of feathers and lilies.

Ancient Egyptians probably new what they were working with. They called meteorite iron from the sky in one hieroglyph. Whether they knew with absolute certainty that their iron meteorites came from the sky, and what that might have meant, they did value the iron. As the authors of the study say, “…our study confirms that ancient Egyptians attributed great value to meteoritic iron for the production of precious objects.”

The authors go on to say, “Moreover, the high manufacturing quality of Tutankhamun’s dagger blade, in comparison with other simple-shaped meteoritic iron artifacts, suggests a significant mastery of ironworking in Tutankhamun’s time.”

90 Years Ago Goddard’s Liquid-Fuelled Rocket Launched Spaceflight

Dr. Robert H. Goddard and a liquid oxygen-gasoline rocket in the frame from which it was fired on March 16, 1926, at Auburn, Massachusetts. Image: NASA/Clark University Robert H. Goddard Archive

The invention of the rocket changed space science forever. The Universe could only be inspected from the surface of the Earth, with all that atmosphere in the way, until rockets were invented. And as far as the modern age of rocketry goes, it all started 90 years ago with Robert Goddard’s liquid-fuelled rocket.

Goddard was a dreamer. He envisioned rocket-powered spacecraft plying the solar system. Obviously, he passed away before interplanetary travel materialized, but his work on rocketry certainly laid the groundwork for that eventual achievement. The Goddard Space Flight Center is named after him, and it’s doubtful that any engineering or technology student in the world doesn’t know who he is.

Goddard’s first liquid-fuelled rocket was modest by today’s standards, of course. But he had to solve several technical challenges to achieve it, and his ability to solve these challenges led to not only this first flight, but to a total of 34 rocket flights in 15 years, from 1926 to 1941. His rockets reached the altitude of 2.6 km (1.6 miles) and speeds of 885 km/h (550 mph.) He also patented 214 inventions.

Goddard is considered the father of modern rocket science, but he is actually one of three men who are considered the main contributors to modern rocketry. Russian Konstantin Tsiolkovsky (1858-1935) and German Hermann Oberth (1894-1989) are the other founding fathers of modern rocketry.

Goddard didn’t invent rocketry, of course. The Chinese used rockets as far back as the 13th century, and rockets made appearances throughout history as weapons and fireworks. But Goddard’s success at liquid-fuelled rocketry, and the capabilities that came with it, is when rocketry really got off the ground. (Sorry.)

Nowadays, Goddard is understood to be a driven and highly-intelligent person, the type of person who is responsible for advancing science and technology. But back in his time, before he had successful flights, he and his ideas were ridiculed. Check out this criticism from the New York Times, January 13th, 1920:

“That Professor Goddard, with his ‘chair’ in Clark College and the countenancing of the Smithsonian Institution, does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react — to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high schools.”

Stinging words, to be sure, but people who know anything about the history of science are familiar with this kind of condemnation of brilliant people, coming from those who lack vision.

Now of course, we have huge rockets. Great thundering beasts that lift enormous loads out of Earth’s gravity well. And we’re so accustomed to rocket launches now that they barely make news. But I always get a kick out of imagining what people like Goddard would feel if they were able to view a launch of one of today’s behemoths, like the Ariane 5. I’m sure his chest would swelled with pride, and he would be amazed at what people have accomplished.

But his vindication wouldn’t just come from the huge leaps we’ve made in rocket technology, and the huge rockets we now routinely launch. It would also come from this retraction, delivered decades too late but with class, by the New York Times, on July 17 1969, the day after Apollo 11 launched:

Further investigation and experimentation have confirmed the findings of Isaac Newton in the 17th Century and it is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error.

Challenges We’re Overcoming Following the Challenger Accident

It was thirty years ago, January 28, 1986, that space shuttle Challenger exploded 73 seconds into its flight, killing seven astronauts. This is a tough time of year in the history of human spaceflight, as 19 years on January 27, 1967 three astronauts died in a fire in the module of Apollo 1. Then on February 1, 2003, space shuttle Columbia disintegrated as it reentered Earth’s atmosphere, killing all seven crew members.

Remembering these events brings home the fact that even today, spaceflight remains far from routine. But over the years, what else have we learned from these tragedies?

I recently touched base with long-time NASA engineer Jerry Woodfill, whose name you may recall from our two series about Apollo 13 — 13 Things That Saved Apollo 13 and 13 More Things That Saved Apollo 13.

Christa McAuliffe. Credit: Challenger's Lost Lessons
Christa McAuliffe. Credit: Challenger’s Lost Lessons

But Jerry was also featured in an article we did in 2008. A year earlier he came across a file of papers from 1985 that proposed how teacher Christa McAuliffe’s eight lessons would be performed on orbit as part of the Challenger mission. Woodfill worked to find old videos, photographs and other materials that had been tucked away in sadness and grief following the loss of Challenger and put together lesson plans and gave them to the Challenger Center. The lessons are available on the Center’s website.

Jerry and I discussed other “lessons” that may have been learned from the tragedies, and he had some interesting ideas about paradigm shifts that have occurred over the past 30-plus years. Here are a few “old” ideas that have changed or are in the process of changing:

Civilians, especially women should not be launched on risky missions to space

The 2013 astronaut candidate class. Front row, left to right: Jessica Meir, Christina Hammock, Andrew Morgan. Back row (left to right), Anne McClain, Nicole Mann, Tyler (Nick) Hague, Josh Cassada and Victor Glover. Credit: NASA
The 2013 astronaut candidate class. Front row, left to right: Jessica Meir, Christina Hammock, Andrew Morgan. Back row (left to right), Anne McClain, Nicole Mann, Tyler (Nick) Hague, Josh Cassada and Victor Glover. Credit: NASA

We’re certainly beyond the “women can’t do what men can” in our society (for the most part, anyway), and NASA’s last class of astronauts was 50% women (4 out of 8). It did take NASA until 1978 to hire the first female astronauts.

As far as civilians being part of space flight…. that’s the whole point the pioneers of spaceflight did what they did, to try and make flying to space as routine as flying in an airplane.

“While we’re not quite there yet,” said Woodfill, “the prospects for civilian space travel is altogether more plausible. “Now we have a maturing commercial space paradigm that wholly embraces the idea of everybody someday being eligible for a trip to space.”

Woodfill also mentioned that he used to hear that some people thought the idea that a Challenger-like mission should never be attempted again.

“That is refuted by the Challenger’s Lost Lessons project in 2008 and how much these recovered lessons mean to the families of the crew,” he said, “ and to the teachers that are now using these lessons in their classrooms.”
McAuliffe’s backup, Barbara Morgan completed her space shuttle flight in 2007 as a mission specialist, doing special education activities during the mission.

Nothing good can come of such a tragedy.

“An obvious challenge to such a posture was a redesigned, safer, more robust Solid Rocket Booster system,” Woodfill said. “In fact, it led to the work-horse SRBs adapted and upgraded for the Space Launch System (SLS) which will likely take us to Mars.”

The tragedies have provided lessons to be learned. “Go-fever” has been tempered with a more analytical view of each mission and the potential risks it entails. Crew safety at NASA has become top priority. All NASA workers are told to “speak up” if they see something that might compromise any mission.

Human spaceflight is too risky.

Dr. Robert H. Goddard (second from right) and his colleagues hold a liquid-propellant rocket in 1932 at their New Mexico workshop. Credit: NASA Goddard Space Flight Center
Dr. Robert H. Goddard (second from right) and his colleagues hold a liquid-propellant rocket in 1932 at their New Mexico workshop. Credit: NASA Goddard Space Flight Center

This debate will likely continue, but ask anyone associated with spaceflight and they’ll tell you they know the risks and that it’s all worth it for what it means for humanity. You can read Neil de Grasse Tyson’s ideas about this here.

National Geographic is currently running a show they produced called “Challenger Disaster: Lost Tapes,” that shows some old footage shot at NASA following the accident. Shown is then-Vice President George H.W. Bush and astronaut and Senator John Glenn who met with NASA’s space shuttle launch team at Kennedy Space Center in Florida. Bush said he met with the families of the lost astronauts and relayed that they pleaded that the space shuttle program continue “forward full speed.”

Glenn said, in part, “We’ve had tremendous triumph. …. And with this program, we’ve succeeded. Really, if we’re honest about it, beyond our wildest dreams. I would have never thought we’d go this far without losing some people, at something where you’re going at 5 miles a second, with the heat of reentry and the complexity of a system where everything has to go right. Now, we have a tragedy that goes along with our triumphs. I guess that’s the story of mankind.”

As many have said, the future doesn’t belong to the faint of heart, and it is part of human nature to explore and push the boundaries. But there are always lessons to be learned and ideas to be challenged. That’s part of the story of humankind, too.

Find out more about the National Geographic special here.

What Is The Geocentric Model Of The Universe?

The Geocentric View of the Solar System

During the many thousand years that human beings have been looking up at the stars, our concept of what the Universe looks like has changed dramatically. At one time, the magi and sages of the world believed that the Universe consisted of a flat Earth (or a square one, a zigarrut, etc.) surrounded by the Sun, the Moon, and the stars. Over time, ancient astronomers became aware that some stars did not move like the rest, and began to understand that these too were planets.

In time, we also began to understand that the Earth was indeed round, and came up with rationalized explanations for the behavior of other celestial bodies. And by classical antiquity, scientists had formulated ideas on how the motion of the planets occurred, and how all the heavenly orbs fit together. This gave rise to the Geocentric model of the universe, a now-defunct model that explained how the Sun, Moon, and firmament circled around our planet.

Continue reading “What Is The Geocentric Model Of The Universe?”

Timeline of the Universe, From the Big Bang to the Death of Our Sun

A teeny, tiny, minuscule portion of Martin Vargic’s Timeline of the Universe.

Don’t know much about history? How about the future? A new infographic by graphic designer Martin Vargic portrays both past and forthcoming events in our Universe, from the Big Bang to the death of our Sun. The graphic is color-coded and shows “significant events in cosmic and natural history.” It also illustrates how briefly humanity has been part of the scene.

Fun future events are when Earth’s day will become 25 hours long (Earth’s rotation is slowing down), and the amazingly distant time when the Solar System finally completes one orbit around the galactic core.

The full infographic is below, and be prepared to give your scroll wheel a workout. This thing is huge, but very comprehensive for covering about 23.8 billion years!
Continue reading “Timeline of the Universe, From the Big Bang to the Death of Our Sun”

New NASA Documentary Chronicles 50 Years of Spacewalks

Spacewalks have been described by astronauts as magical, amazing, and “holy moly!” This new 30-minute NASA documentary called “Suit Up!” celebrates 50 years of extravehicular activity (EVA) or spacewalks. 50 years ago this year, the first spacewalks were conducted by Russian Alexei Leonov in March 1965 and then American astronaut Edward White followed soon after in June 1965. The documentary features interviews with astronauts past and present, as well as other astronauts, engineers, technicians, managers from the history of spacewalks.

They share their personal stories and thoughts that cover the full EVA experience — from the early spacewalking experiences, to spacesuit manufacturing, to modern day spacewalks aboard the International Space Station as well as what the future holds for humans working on a tether in space.

“Suit Up,” is narrated by actor and fan of space exploration Jon Cryer.

For more info, NASA has a special page with images and more recollections. Also, here is a list of some of the most memorable spacewalks, and here are some 3-D views of humanity’s first spacewalk by Leonov.

Beyond “Fermi’s Paradox” I: A Lunchtime Conversation- Enrico Fermi and Extraterrestrial Intelligence

It’s become a kind of legend, like Newton and the apple or George Washington and the cherry tree. One day in 1950, the great physicist Enrico Fermi sat down to lunch with colleagues at the Fuller Lodge at Los Alamos National Laboratory in New Mexico and came up with a powerful argument about the existence of extraterrestrial intelligence, the so-called “Fermi paradox”. But like many legends, it’s only partly true. Robert Gray explained the real history in a recent paper in the journal Astrobiology.

Enrico Fermi was the winner of the 1938 Nobel Prize for physics, led the team that developed the world’s first nuclear reactor at the University of Chicago, and was a key contributor to the Manhattan Project that developed the atomic bomb during World War II. The Los Alamos Lab where he worked was founded as the headquarters of that project.

The line of reasoning often attributed to Fermi, in his lunchtime conversation, runs like this: There may be many habitable Earth-like planets in our Milky Way galaxy. If intelligent life and technological civilization arise on any one of them, that civilization will eventually invent a means of interstellar travel. It will colonize nearby stellar systems. These colonies will send out their own colonizing expeditions, and the process will continue inevitably until every habitable planet in the galaxy has been reached.

The fact that there aren’t already aliens here on Earth was therefore supposed to be strong evidence that they don’t exist anywhere in the galaxy. This argument actually isn’t Fermi’s and was published more than 25 years later by astronomer Michael Hart. It was elaborated in a paper published by the cosmologist Frank Tipler in 1980.

Fermi’s lunch conversation really did happen. Although he died just four years later of cancer, physicist Eric Jones published the recollections of the physicist’s luncheon companions more than thirty five years later. Among these companions were Edward Teller, Emil Konopinski, and Herbert York, all eminent physicists and veterans of the Manhattan Project. Teller played a central role in the development of the hydrogen bomb. Konopinski studied the structure of the atomic nucleus, and York became director of Lawrence Livermore National Laboratory.

Edward Teller was the head of the Theoretical Physics Division at Los Alamos National Laboratory during the Manhattan Project that developed the atomic bomb for World War II. After the war he was central to the development of the hydrogen bomb.
Edward Teller headed a group in the Theoretical Physics Division at Los Alamos National Laboratory during the Manhattan Project that developed the atomic bomb for World War II. After the war he was central to the development of the hydrogen bomb. He was one of Enrico Fermi’s lunch companions when he posed the famed question”Where is everybody?” Credit: Lawrence Livermore National Laboratory

During the walk to the Fuller Lodge, the physicists discussed a recent spate of UFO sightings, and a cartoon in the New Yorker Magazine depicting aliens and a flying saucer. Although the topic of conversation moved on as the group sat down for lunch, Edward Teller recalls “in the middle of the conversation, Fermi came out with the quite unexpected question ‘Where is everybody?’…The result of his question was general laughter because of the strange fact that in spite of Fermi’s question coming out of the clear blue, everybody around the table seemed to understand at once that he was talking about extraterrestrial life”.

In his account of the famed luncheon, Teller wrote “I do not believe much came from this conversation, except perhaps a statement that the distances to the next location of living beings may be very great and that, indeed, as far as our galaxy is concerned, we are living somewhere in the sticks, far removed from the metropolitan area of the galactic center”.

York recalled a somewhat more expansive discussion in which Fermi “followed up with a series of calculations on the probability of earthlike planets, the probability of life given an earth, the probability of humans given life, the likely rise and duration of high technology, and so on. He concluded on the basis of these calculations that we ought to have been visited long ago and many times over”.

According to York, Fermi supposed the reason we hadn’t been visited “might be the interstellar flight is impossible, or if it is possible, always judged not worth the effort, or technological civilization doesn’t last long enough for it to happen”.

So Fermi, unlike Hart, wasn’t skeptical about the existence of extraterrestrials, and didn’t view their absence from Earth as paradoxical. There is no Fermi paradox, there is simply Fermi’s question “Where is everybody?”, to which there are many possible answers. The answer that Fermi preferred seems to be that, either interstellar travel isn’t feasible because of the enormous distances involved, or Earth simply had never been reached by alien travelers.

Herbert York was a Manhattan Project physicist, the co-discoverer of the neutral pi meson, and the first director of the Lawrence Livermore National Laboratory.  He was one of Fermi's lunch companions the day he posed his famed question about extraterrestrials.  Credit: National Nuclear Security Administration
Herbert York was a Manhattan Project physicist, the co-discoverer of the neutral pi meson, and the first director of the Lawrence Livermore National Laboratory. He was one of Fermi’s lunch companions the day he posed his famed question about extraterrestrials. Credit: National Nuclear Security Administration

Interstellar distances are truly vast. If the entire solar system out to the orbit of Neptune were reduced to the size of an American quarter, the nearest star, Proxima Centauri, would still be about the length of a football field away. A practical starship would either need to travel very fast, at an appreciable fraction of the speed of light, or be capable of supporting its crew for a very long time. While either is theoretically possible, interstellar travel seems to present day humanity to be such a grandiose undertaking that it’s not clear whether any civilization would be able or willing to muster the enormous resources needed.

Where did the confusing of Fermi’s question with Hart’s argument come from? Carl Sagan mentioned Fermi’s question in a footnote to a 1963 paper. After the publication of Hart’s paper in 1975, Fermi’s question and Hart’s speculative answer became associated in many writer’s minds. Fermi’s question seemed to beg Hart’s answer, and “Fermi’s paradox” was born. According to Robert Gray, the term was coined by D. G. Stephenson, in a paper published two years after Hart’s.

Why is it important that Hart’s argument was never really made by the eminent physicist Enrico Fermi? Did Michael Hart and Frank Tipler really make a compelling case that extraterrestrial civilizations don’t exist in our galaxy? We’ll answer those questions in the second installment.

References and Further Reading:

F. Cain (2013) How Could We Find Aliens? The Search for Extraterrestrial Intelligence (SETI). Universe Today.

R. H. Gray (2012) The Elusive WOW, Searching for Extraterrestrial Intelligence, Palmer Square Press, Chicago, Illinois.

R. H. Gray (2015) The Fermi Paradox is neither Fermi’s nor a paradox, Astrobiology, 15(3): 195-199.

M. H. Hart, (1975) An explanation for the absence of extraterrestrials on Earth, Quarterly Journal of the Royal Astronomical Society, 16:128-135.

E. M. Jones (1985) “Where is everybody?” An account of Fermi’s question, Los Alamos National Laboratory.

P. Patton (2014) Communicating Across the Cosmos, Part 1, Part 2, Part 3, Part 4. Universe Today.

F. Tipler (1980) Extraterrestrial intelligent beings do not exist, Quarterly Journal of the Royal Astronomical Society, 21:267-281.

S. Webb (2010) If the Universe is Teeming with Aliens…Where is Everybody? Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life. Copernicus Books, New York, NY.

3-D Views of Humanity’s First Spacewalk, 50 Years Ago Today

On March 18, 1965 Soviet cosmonaut Alexei Leonov made the first spacewalk in history, floating outside his Voskhod 2 capsule. Leonov made the walk when he was just 30 years old, and later wrote that he felt “like a seagull with its wings outstretched, soaring high above the Earth.” His spacewalk lasted just 12 minutes but that was long enough to prove that humans in space could work outside a spacecraft.

Author and space historian Andrew Chaikin created some unique 3-D views of Leonov’s spacewalk, made from individual frames from the movie of the walk. Above is a red-cyan anaglyph, but if you don’t have your 3-D glasses available, don’t worry: Chaikin has also created stereo pair 3-D images, which you can view by crossing your eyes (explanation below, if you need a little help).

Alexei Leonov during the first ever spacewalk on March 18, 1965. Cross-eyed 3-D stereo pair created from individual frames from the movie of the walk. Credit: Andrew Chaikin.
Alexei Leonov during the first ever spacewalk on March 18, 1965. Cross-eyed 3-D stereo pair created from individual frames from the movie of the walk. Credit: Andrew Chaikin.

Oxford University provides this explanation of how to cross your eyes to view a stereo pair as a 3-D image:

Hold a finger a short distance in front of your eyes and stare at it. In the background you should see two copies of the stereo pair, giving four views altogether. Move your finger away from you until you see the middle two of the four images come together. You should now see just three images in the background. Try to direct your attention slowly toward the middle image without moving your eyes, and it should gradually come into focus.

Alexei Leonov during the first ever spacewalk on March 18, 1965. 3-D anaglyph created from individual frames from the movie of the walk. Credit: Andrew Chaikin.
Alexei Leonov during the first ever spacewalk on March 18, 1965. 3-D anaglyph created from individual frames from the movie of the walk. Credit: Andrew Chaikin.

While the spacewalk was exhilarating, getting back into the spacecraft became dicey. Leonov’s spacesuit expanded so much in the vacuum of space that he had a hard time squeezing back into the spacecraft. He took a risk and opened a valve on the suit to let enough air escape, which allowed him to enter the airlock.

Leonov’s walk took place almost 3 months before American astronaut Ed White took his spacewalk on Gemini 4. The first European to do a spacewalk was the French spationaute Jean-Loup Chrétien, who flew to the Russian Mir space station in 1988.

Alexei Leonov during the first ever spacewalk on March 18, 1965. Cross-eyed 3-D stereo pair created from individual frames from the movie of the walk. Credit: Andrew Chaikin.
Alexei Leonov during the first ever spacewalk on March 18, 1965. Cross-eyed 3-D stereo pair created from individual frames from the movie of the walk. Credit: Andrew Chaikin.
Alexei Leonov during the first ever spacewalk on March 18, 1965. 3-D anaglyph created from individual frames from the movie of the walk. Credit: Andrew Chaikin.
Alexei Leonov during the first ever spacewalk on March 18, 1965. 3-D anaglyph created from individual frames from the movie of the walk. Credit: Andrew Chaikin.

Alexei Leonov during the first ever spacewalk on March 18, 1965. Cross-eyed 3-D stereo pair created from individual frames from the movie of the walk. Credit: Andrew Chaikin.
Alexei Leonov during the first ever spacewalk on March 18, 1965. Cross-eyed 3-D stereo pair created from individual frames from the movie of the walk. Credit: Andrew Chaikin.

Thanks to Andrew Chaikin for sharing these images with Universe Today.

Here is some color footage of the spacewalk:

The BBC has created a special webpage to celebrate the 50th anniversary of Leonov’s spacewalk. ESA has a gallery of images from 50 years of spacewalks.

Group photo of the first cosmonauts. Taken just after the flight of Voskhod 2 in 1965, in order of flight (from left), the first Soviet cosmonauts: Yuri Gagarin, Gherman Titov, Andrian Nikolayev, Pavel Popovich, Valeri Bykovsky, Valentina Tereshkova, Konstantin Feoktistov, Vladimir Komarov, Boris Yegorov, Pavel Belyayev and Alexei Leonov. Alexei had just returned to Earth after performing the first spacewalk in history during the Voskhod 2 mission. Credit: alldayru.com, via ESA.
Group photo of the first cosmonauts. Taken just after the flight of Voskhod 2 in 1965, in order of flight (from left), the first Soviet cosmonauts: Yuri Gagarin, Gherman Titov, Andrian Nikolayev, Pavel Popovich, Valeri Bykovsky, Valentina Tereshkova, Konstantin Feoktistov, Vladimir Komarov, Boris Yegorov, Pavel Belyayev and Alexei Leonov.
Alexei had just returned to Earth after performing the first spacewalk in history during the Voskhod 2 mission.
Credit: alldayru.com, via ESA.

How Did We Find the Distance to the Sun?

How far is the Sun? It seems as if one could hardly ask a more straightforward question. Yet this very inquiry bedeviled astronomers for more than two thousand years.

Certainly it’s a question of nearly unrivaled importance, overshadowed in history perhaps only by the search for the size and mass of the Earth. Known today as the astronomical unit, the distance serves as our reference within the solar system and the baseline for measuring all distances in the Universe.

Thinkers in Ancient Greece were among the first to try and construct a comprehensive model of the cosmos. With nothing but naked-eye observations, a few things could be worked out. The Moon loomed large in the sky so it was probably pretty close. Solar eclipses revealed that the Moon and Sun were almost exactly the same angular size, but the Sun was so much brighter that perhaps it was larger but farther away (this coincidence regarding the apparent size of the Sun and Moon has been of almost indescribable importance in advancing astronomy). The rest of the planets appeared no larger than the stars, yet seemed to move more rapidly; they were likely at some intermediate distance. But, could we do any better than these vague descriptions? With the invention of geometry, the answer became a resounding yes. Continue reading “How Did We Find the Distance to the Sun?”