Should We Call Pluto a Planet?

Astronomers once called Pluto the ninth planet. In 2006, the International Astronomical Union, IAU, downgraded Pluto to the status of dwarf planet. After the New Horizons craft flew by Pluto in 2015, it showed us a very dynamic world. Many astronomers and a large percentage of the public now believe we should reconsider Pluto’s demotion.

Pluto as seen by the New Horizons spacecraft. 

Since before written history, humans have known of seven regularly observed heavenly bodies that didn’t behave like the vast majority of stars. They called them planets, Greek for “wanderer.” In those ancient times, they considered anything that changed its position relative to the “fixed stars” to be a planet. Since both the sun and the Moon moved relative to the fixed stars, they were also considered planets until Copernicus proved that planets circled the sun and the Moon circled Earth.

Astronomers then recognized six planets, Mercury, Venus, Earth, Mars, Jupiter, and Saturn. Comets also orbited the sun, but because they had weird orbits and grew a tail, they were considered different types of celestial objects. That changed in 1781 when William Herschel discovered Uranus and Italian astronomer Giuseppe Piazzi discovered Ceres in 1801 between Mars and Jupiter while searching for comets. Both orbited the sun.

Ceres, the largest member of the Asteroid Belt.

Initially, astronomers called Ceres the smallest planet until many more such objects were discovered in the same area of our solar system. They reclassified Ceres and all those other even smaller objects as “asteroids,” calling that region the Asteroid Belt.

In 1846, two astronomers independently discovered Neptune, adding an 8^th planet to the solar system. Clyde Tombaugh added Pluto in 1930, making nine planets, and there it stayed for years.

In the 1990s, astronomers began finding many more objects beyond Neptune. They were small like Pluto and in the area of our solar system that was relatively crowded, unlike the inner parts. Some astronomers feared that it might be time to get a more scientifically based definition of “planet.”  

At the 2006 IAU meeting, astronomers agreed to redefine what constitutes a planet. There were two camps: geophysicists and dynamists. They all agreed that it had to orbit a star. Geophysicists said that any object big enough that its gravity pulled it into a spherical or nearly spherical shape should be a planet. Dynamists argued that a planet must also be large enough to “clear its orbital area of debris.” Ceres couldn’t be a planet since, even though it is round, there were many asteroids in the same region. Likewise, round Pluto shared its region with many thousands of objects.

The dynamists won. Pluto, Ceres, and other round solar system bodies became dwarf planets. Along with those two, astronomers now recognize three others, Haumea, Makemake, and Eris, all beyond Neptune, as dwarf planets. There may be many more that we just don’t have enough data on yet.

Count me in the camp of the geophysicists. If it’s big enough to pull itself into a nearly circular shape, technically called hydrostatic equilibrium, then I believe it should be a planet. I’m convinced that the dynamists just didn’t want to remember that many planet names.

  

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

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

Did Earth Once Possess a Ring Like Saturn?

 When I show people astronomical sights through my telescope, the one view that elicits the most comments is Saturn with its rings. Many times I’ve heard people say “Wow! That’s amazing.” Or, “Oh, that’s not real. You have a picture in there.” Saturn, more than any other common backyard telescope target, looks like the pictures you’ve seen in books.

Saturn.

Saturn isn’t the only planet with a ring system. Jupiter, Uranus, and Neptune also have rings but are only visible with very powerful telescopes or spacecraft passing nearby.

Imagine the sense of awe if we lived on a planet with rings, something we sometimes see in science fiction movies. Had you been around on Earth 466 million years ago, you might have been able to enjoy that very experience. A recent study suggests that Earth may very well have sported a ring like Saturn.

Artist's conception of Earth with rings.

Planetary rings are ephemeral. They don’t last forever, although they do exist for millions of years. The evidence for Earth’s possible ring is circumstantial but quite intriguing. Starting about 466 million years ago, Earth experienced a period of enhanced meteor cratering, a period known as the Ordovician impact spike. During that cratering period, virtually all of the impacts on Earth, centered on a narrow band along the equator. Typically, impacts should occur randomly over the Earth’s surface.

This narrow cratering band implies that the objects striking Earth all came from that area of the sky over the equator. The easiest explanation for such a narrow band of cratering events along the equator is a ring of debris encircling our planet. If a ring forms around a planet, it will always settle over the equator.

During the same time frame, sedimentary rocks show a large increase in L chondrite material. L chondrite-type asteroids are common in the asteroid belt. Denizens in the asteroid belt occasionally collide, scattering debris around the solar system. 

Artist's conception of two asteroids colliding. 

The researchers, led by Andrew G. Tomkins, a geologist at Monash University in Australia, suggest that one large fragment came close to Earth, passing so closely that Earth’s gravity shattered it and the debris formed a ring.

Based on the cratering record, the study participants claimed the ring lasted approximately 40 million years, a typical lifetime for a planetary ring. During that same period of time, Earth experienced one of its most intense glaciation events and mass extinctions known as the Hirnantian global icehouse period. The researchers suggest that shading from the ring decreased solar radiation reaching the planet’s surface, triggering the short but intense glaciation period. “The existence of such a ring, forming around 466 million years ago and persisting for a few tens of millions of years could explain several puzzles in our planet’s past,” Tomkins wrote.

None of this evidence is absolute proof that we once had a ring like Saturn’s, but it is strongly suggestive. More work needs to be done to help corroborate their conclusion.

 

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

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

How the Moon May Save Our Plants and Animals

        As you start reading this article, you’ll likely wonder what this has to do with astronomy. But stay

 with me. Astronomy may play a pivotal role in helping solve this problem.

Species extinctions, both plant and animal, happen all the time. Scientists estimate that some 10% of species go extinct every 10 million years. One estimate claims that 99.999% of all species that have ever lived on Earth have gone extinct. But there are times in the vast history of life on Earth where species vanished at much higher rates, events known as mass extinctions. Scientists recognize five major mass extinctions. And some feel we are now at the beginning of a sixth one, this one caused primarily by human activity, like habitat destruction, overhunting, pollution, and global warming. Over the past few hundred years, extinctions climbed over 1000 times the background rate. 

To protect the world’s plant species, particularly those used for food, the Svalbard Global Seed Vault was established in 2008 to preserve global agricultural biodiversity. An international consortium chose a site on the Norwegian island of Spitsbergen. Ice, snow, and frozen tundra covered the island. This extreme cold would preserve the seeds stored there in case of an agricultural disaster.  It houses over one million varieties of seeds.

Svalbard Global Seed Fault

  In 2017, global warming caused heavy rain on the island instead of the normal snowfall. The vault flooded, although the water did not reach the seeds. This led to researchers brainstorming a way to protect the seeds against such disasters. And, other researchers wanted to also preserve animals in danger of extinction by securely storing DNA in cryogenic deep freeze. But, where could such a repository be constructed that wouldn’t be at the mercy of power loss, wars, or global warming?

Many scientists are now considering the Moon as the ideal location. At the Moon’s South Pole, astronomers have discovered numerous craters that exist in perpetual shadow. Sunlight never reaches the bottom of these craters. Since the Moon has no atmosphere to spread warmth from the sun, these permanently shadowed regions remain at around -196 degrees, the minimum needed to protect animal cells long-term.

Lunar craters near the South Pole that have permanently shadowed areas. Temperatures here never get above -195 degrees Fahrenheit.

 

This may seem like a wild idea, but as research scientist Mary Hagedorn, of the Smithsonian National Zoo and Conservation Biology Institute in Washington D.C. says, “It’s very good to have as many plans as possible, especially when it comes to saving our biodiversity and life on Earth.” 

Scientists have numerous satellites orbiting the Moon, and the data they send back just may help us save animals from extinction and important agricultural plants from natural or manmade disasters.

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

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

 

 

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.

NASA Innovative Advanced Concepts Awards

 Every year, NASA offers preliminary funding to several unusual projects. The NASA Innovative Advanced Concepts (NIAC) program “nurtures visionary ideas that could transform future NASA missions with the creation of breakthroughs – radically better or entirely new aerospace concepts.” Some of the past NIAC award-winning ideas that became a reality include the Ingenuity helicopter now flying on Mars and Cubesats, small one-foot cube satellites that can use smartphones as the onboard computers. You’ve always heard how powerful of a computer your iPhone is! Other funded NIAC proposals include such diverse projects as the 3-D printing of biomaterials such as arrays of cells and a proposal to use the sun as a gravitational lens to study exoplanet surfaces. One idea proposes using bacteria and fungi brought from Earth plus known gases and soil materials on Mars to create bioengineered building materials. This dramatically reduces the weight needed to be sent to Mars to create safe habitats for future Martian astronauts.

NASA awarded 13 new NIAC awards in 2023 for projects beginning this year. The two most exciting for me are a Venus Sample Return mission and sending a cluster of microsatellites to study the nearest exoplanet.

Over four decades ago, the Soviet Union landed multiple Venera probes on Venus. But conditions on Venus quickly overwhelmed them. Surface temperatures reach nearly 900 degrees, hot enough to melt lead. Atmospheric pressure is ninety times that on Earth. Although each of the 10 landers provided valuable information about the planet, the longest-lasting probe, Venera 12, only lasted 110 minutes.

One NIAC award went to a team that wants to use the high-temperature technology developed for probes that study the sun up close plus an innovative rocket engine design that can use fuel created from the gasses in the Venusian atmosphere to return samples from the surface of the planet. Venus may once have been much like Earth, but the runaway greenhouse conditions turned it into a hellish environment. This mission might allow us to better understand the conditions on Venus before that change.

The surface of Venus from Venera 13. Credit Russian Science Academy

The closest star to us, Proxima Centauri, is 4.2 light years, 25 trillion miles, distant. Using our current fastest rocket technology, it would take us more than 50,000 years to reach it. A roughly Earth-sized planet, Proxima Centauri B, orbits the star. One NIAC award went to a group to study the feasibility of sending thousands of tiny spacecraft to study that planet. They plan to power them using a 100-gigawatt laser beamed at the swarm from Earth. The tiny crafts would work together creating the equivalent of a giant dish antenna to send signals back to Earth. They estimate the trip would take only 20 years and data returned at the speed of light requires only 4.2 years.

The nano-spacecraft would take 20 years to reach Alpha Centauri. Credit Breakthrough Starshot

Only a handful of NIAC awards lead to actual NASA missions. I hope these two come to full fruition.

 

Watch a Dragon Eat the Sun!

NOTE: Although this column is written for Oklahomans, the links in the article give information about where else in the United States you can see this total solar eclipse.

Imagine life as a human 10,000 years ago. If you are male, much of your time is spent hunting game by yourself or with other men in your group. Some animals were easy to catch, like rabbits or even deer. But hunting bigger animals, like mastodons, could prove dangerous, even deadly. If you’re female, much of your time is spent gathering nuts, berries, or other edible plants and taking care of infants. One of your most dangerous jobs is childbirth. 

At times, your survival might be severely threatened. Bad weather, wildfires, and animal stampedes, all can make life miserable.

Now, imagine a bountiful summer. Food is plentiful, your cave or hut protects you from wild animals and bad storms. But as you finish your afternoon meal, you notice something odd. The light seems different, muted, like a hazy sky. But, the sky is perfectly clear. Moment by moment, the sun’s light slowly fades. Animals start acting oddly, too. Birds began to roost in the middle of the day. Herd animals form circle groups as they do when they protect their young at night. 

You squint at the sun and gasp. Half of it is missing! The light dims more as the sun disappears. Just as it vanishes, yellow petals seem to sprout from a central dark mass. Your tribe fears a demon or dragon is eating the sun. You start screaming, banging rocks and sticks together, anything to make as much noise as possible, hoping to scare away the beast.

Dragon eating the sun, creating an eclipse.

Your efforts pay off as the beast slowly regurgitates the sun.

That’s how our distant ancestors likely reacted to a total solar eclipse. But we know better today. No dragon eats the sun. Rather, the Moon occasionally slides in front of it, blocking its light for a few minutes.

You have a chance in Oklahoma to witness this scary dragon devour our sun, and you should start planning now.

Total solar eclipse revealing the sun's corona.

A total solar eclipse occurs in Oklahoma on April 8, 2024, beginning at 1:44 pm CDT with the final exit of the Moon’s shadow from the state at 1:51 pm CDT. As it passes through Oklahoma, the Moon’s shadow will accelerate from 1680 miles to 1745 miles per hour. The path of totality cuts through the far southeast corner of Oklahoma after passing through the Dallas-Fort Worth Metroplex and heading northeast. Prime viewing sites may get crowded, so start planning your eclipse expedition. Visit tinyurl.com/3du4z57e for more specifics about the eclipse including a detailed map of the path in Oklahoma. More information, including weather prospects, can be found at eclipsophile.com/2024tse/.

And, if you miss this eclipse, you have a while to wait for the next one. We won’t get another total solar eclipse visible from the central United States until August 12^th, 2045.

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.