A Possible Signature of an Advanced Civilization

 As we humans grow in numbers and technological sophistication, we will need to generate more and more energy for our use. That likely means ever more reliance on renewable sources of energy like solar and wind energy. Even so, there will come a point when we have tapped all available energy sources our planet has.

We do, however, live quite close to an almost endless source of energy: our sun.

In 1960, physicist Freeman Dyson proposed that an advanced civilization might dismantle all the other planets, asteroids, and everything else in its solar system to create a sphere surrounding its star to collect all the solar energy it emits to run the civilization. Because of the 2^nd Law of Thermodynamics, such a Dyson Sphere would necessarily radiate excess heat in the form of a strong infrared glow. Dyson suggested that we could detect excess IR radiation from any such civilizations in our galaxy.

Illustration Dyson Sphere under construction 

Credit dottedhippo-iStock-Getty Images Plus

If a civilization is in the process of building a Dyson sphere around its star, we should detect periodic dimming of the star as the completed parts orbit it. Those dips in brightness would look different than a planet orbiting the star, of which we have discovered thousands. A Jupiter-like planet would block less than one percent of the star’s light.

In 2015, astronomer Tabetha “Tabby” Boyajian discovered a star that displayed light dips of up to 22 percent. Astronomers dubbed it Tabby’s Star. Initially, they thought that this star had hundreds of comets in a cluster that crossed in front of the star. However, observations ruled that out. Many armchair scientists, and even a few astronomers, suggested it might be an incomplete Dyson sphere. With more observations, most astronomers accepted that the most likely cause of the light variations is a large dust cloud, probably from a moon that had shattered, and parts of the dust cloud periodically blocked some of the star’s light.

The hallmarks of a Dyson sphere can be summed up easily: variability in a star’s brightness and an excess of IR radiation of a particular pattern due to waste heat. With Tabby’s star, the IR excess doesn’t exactly match a Dyson sphere. The cloud of dust fits it better.

Artist's conception of a partial Dyson Sphere around Tabby's Star

Recently, two separate studies looked at the data from 3 satellite missions that have examined millions of stars in the Milky Way looking for Dyson sphere candidates. One group led by PhD student Matías Suazo at Uppsala University in Sweden describes their study as “searching for extraterrestrial intelligence using indirect signatures of astroengineering,” in other words Dyson spheres. They came across more than a few compelling candidates. Fifty-three to be exact, stars that possessed both accepted signatures of Dyson spheres.

Neither group has yet convinced the astronomical community at large that they have indeed found Dyson spheres, but most agree the studies are intriguing and need further study.

In 1964, a Soviet astronomer Nikolai Kardashev proposed a method of measuring a civilization’s level of technological sophistication. He determined a civilization’s level by the energy sources it can utilize. According to the Kardashev Scale, a type I civilization can utilize and control all the energy sources of its home planet. That would include taming and using the energy of natural events such as volcanoes, tornadoes, earthquakes, etc.

A Type II civilization captures and uses all the available energy of its host star by creating a Dyson sphere. A Type III civilization captures all the energy emitted by its galaxy, every star, black hole, etc. Earth is currently considered to be a Type 0.7 civilization.

Have we finally found Type II civilizations? Only further study can answer that question.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

This is reprinted with permission from the Oklahoman and www.Oklahoman.com.

 

 

The Amazing Hubble Telescope

 The Hubble Space Telescope has been and continues to be one of humanity’s greatest scientific instruments. With it, astronomers have already made 1.6 million observations and written more than 21,000 scientific papers. It added dramatically to our knowledge of the universe. Being such a complex instrument, NASA designed it so that it could be periodically serviced, replacing parts that wear out over time.  Five servicing missions visited Hubble. The most important was the very first one. It corrected a tiny mistake in the shape of its main mirror, which was off by less than the width of a human hair. The other four service missions replaced items such as batteries, gyroscopes, and electronic boxes, all of which have limited life. On some missions, astronauts installed state-of-the-art science instruments. Each service mission left Hubble a more capable and more productive observatory.

Hubble Space Telescope, credit STSCI, NASA, ESA

And capable it is. It showed us things astronomers never even guessed might be out there. Perhaps the most amazing science it produced came in the form of a series of long-exposure photographs, 342 in all, with a total exposure time of over 100 hours, known as the Hubble Deep Field. They pointed it to an apparently empty spot near the Big Dipper, a patch of sky about the equivalent of a pinhead at arm’s length.

Hubble Deep Field, credit NASA, ESA

Expecting to find maybe a few distant galaxies, the final combined images revealed more than 3,000 galaxies including what were at the time the most distant objects ever seen. The image amazed astronomers with the new data they obtained. That project was such a success that astronomers did another version from a spot in the southern hemisphere sky. With the success of those two images, astronomers then used Hubble to create the Ultra Deep Field image. It was a combination of 800 images taken over eleven and a half days, revealing more than 10,000 galaxies and again setting new distance records.

Hubble Ultra Deep Field, credit NASA, ESA

Hubble’s discoveries range far beyond simply observing thousands of galaxies in apparently empty patches of the sky. It was instrumental in discovering the existence and distribution of Dark Matter. The speed at which a planet orbits the sun depends on its distance from the sun, with planets farther out moving slower due to distance from the sun’s gravity. By the same token, stars at a galaxy’s edge should move slower than those closer in. But Hubble’s measurements showed that stars across the entire galaxy move at virtually the same speed, and move so fast that the gravity from all the matter of the galaxy couldn’t hold the galaxy together. Galaxies had to be embedded in a large shell of gravity-producing but invisible matter. Hubble was able to map the distribution of dark matter around the universe, helping to show it accounts for 85% of the matter in the universe. Using Albert Einstein's prediction that gravity can focus light, Hubble was used to take images of distant objects the light of which is focused by intervening sources of gravity. By studying these, they could measure the gravity from dark matter sources.

Gravitational Lensing from Dark Matter surrounding a galaxy cluster, credit Gravitational lensing, credit NASA, ESA, and J. Lotz

Hubble data measured the speed at which the universe expands, showing that the expansion is speeding up, leading to the discovery of Dark Energy. Hubble helped to verify the existence of exoplanets, those orbiting other stars. Astronomers used Hubble to study the formation and evolution of galaxies. Because of its keen vision, it helped astronomers better understand how stars change with age, the mechanics of supernovas, and the cause of short gamma-ray bursts, a subject that puzzled astronomers for many years. And this is only the tip of Hubble’s accomplishment iceberg.

We no longer have the space shuttle that flew astronauts on all the Hubble servicing missions. Now, it only has two functioning gyroscopes, which enable its precise pointing. Any observation it makes from now on will take more time. Hubble’s end is certainly in sight.

The Webb Space Telescope, Hubble’s successor, has taken the mantle as the best space telescope, but astronomers will still mourn Hubble’s passing whenever its mission finally ends.

 

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

This is reprinted with permission from the Oklahoman and www.Oklahoman.com.

Our Shrinking Moon

 You have probably heard that hot things expand and cold things contract. Maybe you learned that if a lid jar is stuck too tightly for you to open it, you can run hot water over the lid. The heat expands the metal lid, making it looser and therefore easier to open.

You may even experience this at night in your house. During the heating of the day, the wood in your house expands just a bit. In the cooler air of nighttime, the wood shrinks. You may hear this as creaks around your house. That’s not ghosts but rather the wooden parts rubbing together ever so slightly as the wood shrinks. My ghost-phunting team spends a lot of time explaining to homeowners who are convinced their home is haunted that those footsteps they hear are actually the thermal creaks of their house cooling and shrinking ever so slightly causing the wood two-by-fours to rub together. 

Jar lids and houses aren’t the only things that expand and contract when subjected to heat and cold. Any rigid solid object will react to temperature this way. Even rocks. The seasonal heating and cooling cycle is a contributing cause of the erosion of mountains. As the rock heats up in summer months, tiny cracks form that can become filled with moisture. During the cold winter, the water freezes. Water is one material that actually expands when it freezes as the water molecules rearrange into a crystalline pattern. As the ice expands, it widens the cracks, eventually causing bits of the rock to crumble into smaller bits.

Full Moon

Now think of a larger object, much larger, like our Moon. It formed about four and a half billion years ago when a Mars-sized object called Theia slammed into the newly formed Earth. Theia’s molten iron core sank to the center of our planet, joining our molten iron core. Geologists recently identified two large hunks of molten rock surrounding our planet’s core that they believe are remnants of the Theia.

Much of the rocky outer parts of Theia and some of Earth’s rocky surface parts were flung off in the collision and went into orbit around the now larger Earth. That debris eventually coalesced into the Moon. This new Moon slowly cooled and, as it did, it began shrinking. And that shrinking continues today.NASA satellites orbiting the Moon have photographed most of its surface. Planetary geologists have identified numerous scarps on the lunar surface, wrinkles caused by the Moon’s shrinkage. This is the same phenomenon that happens to an apple’s skin. It shrinks as it ages and dries out, causing it to wrinkle, just like our Moon’s surface.

                            An example of a lunar scarp.

Earth sits in the center of our sun’s habitable zone, the region where liquid water can exist on the surface of our planet. Venus orbits just inside the habitable zone. As a result, Earth is a lush planet full of life, while Venus is a hellish planet with surface temperatures hot enough to melt lead. But, if Venus orbited where Earth does, it likely would be a planet with life. It’s just a bit smaller than Earth and made of the same stuff as Earth. But for the specific orbital paths of the two planets, Venus would be a life-bearing planet.

On May 23^rd, NASA announced the discovery of a Venus-sized planet in the habitable zone of the star Gliese 12, only 40 light years away, virtually in our backyard as astronomical distances go. We have no idea if life developed there, but it is certainly a strong candidate for us to study further.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

 This is reprinted with permission from the Oklahoman and www.Oklahoman.com.

A Unique Sight? Every Night.

 Change is inevitable in our lives. We are born and grow older and taller. We might have children and we’ll watch them grow and change. Our hair eventually turns grey, or in my case, falls out. Our eyesight may fade, our joints may become stiffer.

 We grow older as does everyone we know and care about. Birth and death are a constant part of our world. Day turns into night; spring turns into summer. The clothes we wear at different times of the year, even the fashions we wear now as opposed to just a few years ago. But those changes are superficial.

 Would you like to see an absolutely unique sight? One you’ve never seen and one you’ll never see again? Wait until it gets dark, go outside, and look at the night sky. Do you see it? It has never been seen before, and never will again. It is tonight’s sky.

 The sky has never looked exactly as it does tonight and will never do so again.

 We think of the night sky as being constant. Oh, sure, the constellations move across the night sky from east to west, just like the sun in the daytime. The constellations visible in the night sky now will be almost completely different in six months. But, every April 15^th, we see the same stars. The sun will rise in a slightly different location tomorrow than it did today, but in one year, it will return to where it rose this morning.

 But the night sky changes in a way that all those seeming cycles never actually repeat. As the planets move in their annual dance around the sun, their pattern in the sky constantly changes. You’ll never see the exact arrangement of the planets again that you will see tonight.

 

The planets orbiting our sun.

Our planet’s poles slowly move so that the North Pole points to different stars over time, a motion called precession. This means the North Star we have now, Polaris, won’t always be our North Star. That creates subtle changes in the night sky over a 26,000-year period.

 

Precession and the path of the North Pole in the night sky.

 Our sun orbits the center of the Milky Way galaxy, so the exact pattern of stars in the night sky slowly changes. All other stars move under the various gravitational influences that direct their motions as they, too, orbit around the Milky Way.

 New stars are born and old stars die, sometimes with a dramatic effect.

 

The Great Nebula in Orion, where new stars are forming.

 

The Crab Nebula, the remains of a star that died in a supernova explosion.

 

Galaxies move through the universe, sometimes colliding. The larger galaxy then absorbs the smaller galaxy, gaining from the cannibalized galaxy the stars and gas clouds, the places where new stars come into being. Most of those new stars will have new planets orbiting them. Some of those planets will likely create new living beings.

Two galaxies colliding. They will eventually merge into one.

Change is the one constant in our lives. Even our night sky is eternally, if slowly, evolving.

This is the true magic of astronomy. You never get reruns. Each night remains unique. So, enjoy this night sky, because it will be different than any other night throughout time.

 

   

How I Became an Astronomer

 When did you know what you wanted to be when you grew up? Some of you have, perhaps, still not decided, even though you may have been working and earning a living for years or even decades. I knew from a very young age I wanted to be an astronomer.

Even as a child, of 6 years old, I’d go outside with my father at night to look through his telescope. I looked through his copies of “Sky and Telescope” magazines. Even though I rarely understood the articles, I loved looking at the pictures. I started telling everyone in first grade I wanted to be an astronomer. I still have a framed letter that my Mother saved for me in which I asked Santa Claus for a telescope for Christmas.

Something I saw in those old astronomy magazines really solidified that dream for me. Let me see if I can make you understand some of that excitement I felt back then.

Go outside tonight after dark and look up at the night sky. This time of year, the Milky Way, our home galaxy, lies along the horizon. So when you look up at the sky at 10:00, you’re looking out into the universe. Of course, all the stars you see are still part of our galaxy. But, from a dark location, you can see several faint fuzzy spots through an amateur telescope, or even a good pair of binoculars.

Look at the star chart and find the constellations of Virgo, Bootes, Leo, and Coma Berenices. Coma is a small, faint constellation between Bootes and Leo. On those old star charts in the magazine, this region was labeled as the “Realm of the Galaxies.” To my young mind, the Realm of the Galaxies was a magical, mystical location, a place where I connected to the universe!

Because you are essentially looking away from the Milky Way, other galaxies can be easily seen, many millions through the Hubble and Webb space telescopes. But even in my dad’s small, backyard telescope, we could see about half a dozen, more if we went to a really dark location.

I knew they would not look like the amazing photos I saw in the magazine that were taken through large telescopes with high-quality cameras, but I could see them myself! I was visiting the Realm of the Galaxies! I imagined flying through space in my personal rocket ship passing astronomical wonder after wonder. That’s when I knew I wanted to become an astronomer, to learn about everything in the universe, a universe made more real in the Realm of the Galaxies.

A few of the galaxies located in the "Realm of the Galaxies." 

From top to bottom: Messier 65 in Leo, Messier 100 in Coma Berenices, and Messier 61 in Virgo. All credit NASA.

Grown-up me still gets a thrill looking at and studying all those inhabitants of the astronomical zoo. My area of study in college was cosmology, the formation and evolution of the universe as a whole. To this day, I still feel a strong emotional connection to the feeling of looking through a small, backyard telescope at that part of the sky.

Search for Extraterrestrial Life Heating up

Two recent studies have excited scientists interested in looking for extraterrestrial life. Both hint at possible life on other celestial bodies.

The one closest to home comes from the ongoing Juno spacecraft mission studying Jupiter and its moons. Astronomers have long known that one of Jupiter’s moons, Europa, is covered with a thick layer of water ice, and below that icy shell lies an ocean up to 100 miles deep that holds more water than all of Earth’s oceans. The combined gravity of giant Jupiter and Ganymede, the largest moon in our solar system, pull and squeeze Europa, providing the energy to keep that ocean liquid.

That same gravitational tug-of-war may create volcanic vents on the floor of Europa’s ocean. The vents constantly pump minerals into the water, the same circumstance that many scientists believe led to life on Earth.

The latest data from Juno indicates that Europa generates 1000 tons of oxygen every 24 hours. That’s enough oxygen to support one million humans. On Earth, free oxygen is produced by living plants. The bulk of our oxygen comes from tiny algae plants in the ocean using photosynthesis to create food and release oxygen as a byproduct.

The researchers believe that charged particles driven by Jupiter’s strong magnetic field impact the icy shell on Europa and break apart the water molecules to create free oxygen. While the oxygen isn’t produced by life processes, researchers believe that this oxygen can make its way through the icy shell to the ocean below. This oxygen may then accelerate the evolution of any life in the ocean to create more complex creatures, just as happened in Earth’s oceans.

Scott Bolton, Juno’s principal investigator from the Southwest Research Institute in San Antonio, Texas, said, “Our ability to fly close to the Galilean satellites during our extended mission allowed us to start tackling a breadth of science, including some unique opportunities to contribute to the investigation of Europa’s habitability.”

Jupiter's moon Europa, credit NASA

The other study comes from the Webb space telescope. In 2015, NASA’s K2 mission discovered a planet dubbed K2-18b orbiting a cool, red dwarf star. K2-18b sits in the star’s habitable zone where liquid water can exist on the surface. The research study led by Nikku Madhusudhan, a professor at the University of Cambridge, identified methane and carbon dioxide in the planet's atmosphere, a strong indication that the planet could be covered in an ocean.

K2-18b is a sub-Neptune planet, one between the size of Earth and Neptune, but, since no such planet exists in our solar system, we don’t understand their properties very well. "Although this kind of planet does not exist in our solar system, sub-Neptunes are the most common type of planet known so far in the galaxy," said Subhajit Sarkar of Cardiff University, co-author of the study. "We have obtained the most detailed spectrum of a habitable-zone sub-Neptune to date, and this allowed us to work out the molecules that exist in its atmosphere," Sarkar added.

Artist concept of K2-18b, credit ESA, NASA

That spectrum indicated the presence of dimethyl sulfide which only living organisms can produce, at least here on Earth. Is this ocean world teeming with life? It's far too early to know if life exists there says Madhusudhan, and the researchers were quick to point out that more data is urgently needed. ''If confirmed,” he said, “it would be a huge deal and I feel a responsibility to get this right if we are making such a big claim."

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

 

This is reprinted with permission from the Oklahoman and www.Oklahoman.com. 

Can't Afford Musk's Rocket Flight? Try Space Perspective!

 A few dozen very wealthy people have flown to space on ships operated by private spaceflight companies. Two companies, Virgin Galactic and Blue Origin take paying customers above the Karmen Line, 62 miles high, which defines the start of space. Passengers experience brief moments of weightlessness and enjoy an equally brief view of space and our spherical planet below them before plunging back down to Earth. Neither of these two companies takes passengers on orbital flights around Earth. The entire flight takes a matter of minutes, and these passengers pay as much as $25M for the experience. The private passengers must undergo a few days of training for the experience.

While all those spaceflight passengers claim the experience to be well worth the price, that’s not something ordinary people like you and I can afford. But a much cheaper option is about to become available. A company called Space Perspective expects to launch the maiden passenger voyage of its Spaceship Neptune later this year. It’s not a typical rocket. A balloon will carry a lavish, spherical passenger cabin 20 miles high. It won’t technically reach space, but the company claims the view is very similar to the suborbital flights. Passengers will experience the blackness of space and see the curvature of our planet below, but will not experience weightlessness.

Artist's illustration of Spaceship Neptune high in the atmosphere. Credit: Space Perspective

The first Spaceship Neptune capsule, named Excelsior, will have plenty of room to move around in. A company post on social media says “Spaceship Neptune will have the largest windows ever flown to space and a spherical design that allows for the roomiest interior of any human spaceflight capsule ever made" The 16-foot diameter cabin has rows of padded seats facing the multiple giant windows, 5 feet high by nearly 2 feet wide. The capsule even includes a bar station and a bathroom.

The capsule ascends at a leisurely 12 miles per hour, taking two hours to reach the final altitude. This gentle liftoff means passengers don’t feel the multiple g-forces from a traditional rocket launch. Passengers then spend two floating near the edge of space followed by a two-hour descent and a gentle splash down in the ocean. A waiting ship gently lifts the capsule onto its deck, and passengers are out within 15 minutes of landing.

Spaceship Neptune's interior with a view of Earth through the windows. Credit: Space Perspective

Spaceship Neptune creators have strong qualifications. The company’s CEOs, Taber MacCallum and Jane Poynter, also co-founded Paragon Space Development Corp. Life support and thermal control systems from Paragon have been included in the designs of every human-rated spacecraft the United States has ever flown.

While Spaceship Neptune won’t reach true outer space, it surpasses a key boundary called the Armstrong line. This is the height at which air pressure is so low that water will boil at normal body temperature.

The $125,000 ticket price is still rather steep for the ordinary person, but far more affordable than the millions of dollars for a suborbital flight. And the two-hour duration at altitude allows for a memorable time, even if you can’t brag about going to space.