The errant asteroid hurtled through space at 40,000 miles per hour. Tumbling in a wild orbit, it glinted with sunlight as it neared the Earth. At 65-feet wide, the potato-shaped object should have been easily detected but no one saw it coming.
On the morning of February 15, 2013 the asteroid exploded with the force of 500 kilotons of TNT about 15 miles above the city of Chelyabinsk in the Russian Ural Mountains. The fireball was reportedly 30 times brighter than the sun. The shockwave blew out windows in hundreds of buildings and injured more than 1,500 people.
It was Earth’s most powerful meteor strike since 1908 according to NASA, and was the strongest ever detected by the Comprehensive Test Ban Treaty Organization whose infrasound sensors monitor nuclear explosions. By happenstance, they also pick up the low-frequency sound waves given off as meteors are torn apart by the atmosphere.
Both beautiful and terrible, meteors streak across the sky like admonitions. The world has taken note.
Scientists across the globe are scrambling to learn more about the behavior and composition of these flying rocks. Peering into the borderlands of space, they ask: What can we learn from asteroids? Can we stop one from hitting Earth? Can we mine them for precious resources?
In 2014, Europe sent the Rosetta probe to study Comet 67P, as it passed through the inner solar system, and successfully deployed a lander onto its rocky surface. In 2005, Japan’s Hayabusa spacecraft crash-landed on the small, near-earth asteroid Itokawa, yet managed to convey dust samples back to Earth by 2010.
At Washington State University, astrobiologists, geologists, and astrophysicists are taking part in the effort, using meteorites to calculate the age of our planet, question how life first arrived on Earth, and propose that asteroids might one day help us find a new home in the galaxy.
He hands me the meteorite and I marvel at its smooth black surface, cupped with “thumb prints” from a tortuous journey through Earth’s atmosphere. WSU professor emeritus of geology Nick Foit is smiling. “It’s made of iron and nickel, from the core of one of the solar system’s first tiny planets,” he says. “It’s about 5 billion years old.”
Heavy, like a small hand weight, I lift it up into the 10th-floor window of the Webster Physical Science building overlooking the campus and snow-covered Palouse hills beyond. I feel like I’m in an iconic scene from the film 2001: A Space Odyssey. Five billion years.
Foit has been collecting meteorites since his early college days and shows me impressive specimens from nearly every continent. Today, many countries protect meteorites as national treasures, he says, making it more difficult to acquire the rare rocks.
His interest began with a gift from his father—a fragment of the asteroid that formed Meteor Crater near Flagstaff, Arizona. The well-preserved impact crater, nearly a mile in diameter, was formed about 50,000 years ago during a collision with a 160-foot wide asteroid.
Evidence of similar strikes is scattered around the globe, says Foit, ranging from the massive and most ancient Vredefort crater in South Africa (2 billion years), to the infamous Chicxulub crater in Yucatan (65 million years) and the comparatively infant Lonar crater in India (0.5 million years.)
“We are lucky the Russian Chelyabinsk meteor hit Earth with a glancing blow,” Foit says. “If it had come straight down it would’ve done a lot more damage. Its low trajectory also allowed it to spend a long time in the atmosphere creating one of the more spectacular shooting stars in recent memory,” he says.
The evocative, supernatural aspect of shooting stars has troubled humanity for eons. Randomly plummeting from the sky like angry gods in shades of blue, green, or yellow depending on their mineral content, meteors have been revered and feared, as well as put to good use.
Spearheads and other tools were fashioned from meteorites by prehistoric Native Americans and indigenous peoples in Africa, says Foit. Impact glass, created when the intense heat of an asteroid melts surrounding sand, was called “the rock of god” by ancient Egyptians and was discovered in King Tutankhamun’s scarab beetle pendant.
Determining which glass or stone fragment is actually a meteorite can be difficult. Millions of years of erosion can obscure the craters and other evidence. Foit says the presence of “shatter cones” is key. When a meteor slams into the ground, it produces tremendous shock waves that break the underlying bedrock into telltale fluted cones. “When you find one of these shatter cones, it’s proof positive you’ve found a meteorite impact site,” he says.
Besides leaving huge craters, asteroids have at times nearly abolished life itself. The devastating Chicxulub asteroid smashed into the coast of Mexico 65 million years ago, helping to eradicate the dinosaurs. Foit says the impact created a cloud of dust that cooled and darkened the entire planet, changing the climate. “It probably disrupted the weather for decades and caused one of the mass extinctions…it killed almost everything.”
On the other hand, some speculate it was an asteroid that first brought life to Earth.
WSU astrobiologist Dirk Schulze-Makuch is in Germany, where he just took his children to the opening of the new Star Wars movie, The Force Awakens. I dial long distance and after a short pause, I’m speaking with him in Berlin. It’s just before Christmas.
Schulze-Makuch, professor in the School of the Environment, is widely known for his investigations of extraterrestrial life and cosmic biology. He is a leader in the global astrobiology community and recently published a paper on the physical, chemical, and physiological limits of life.
He says scientists don’t expect to find X-Files type aliens in our solar system, “but only tiny microorganisms similar to Earth’s microbes.” The biochemical makeup of these microbes would vary greatly depending upon their environment.
Life on Mars, for example, might be quite similar to water-based life on Earth, says Schulze-Makuch. But it would be very different on Saturn’s largest moon, Titan, where the atmosphere is mostly nitrogen and methane forms the clouds, rain, rivers, and lakes.
I ask his opinion of a 2015 study led by Italian researcher Raffaele Saladino which hypothesizes that the organic building blocks for life arrived on Earth via carbon-rich chondrites, the oldest type of meteorite in the solar system.
“The findings are interesting,” says Schulze-Makuch. “But organic molecules could also have developed on Earth or Mars. From there it’s very complicated to actually make them into a working cell or organism. There are a lot of ideas about how life initially began, but no overarching theory. It remains our biggest puzzle.”
He does think, however, that life could travel to Earth inside a meteorite, just a few centimeters below the surface. He refers to the 1984 discovery of ALH84001 in Antarctica.
Estimated to be 4 billion years old, ALH84001 is the oldest meteorite ever determined to have come from Mars. The rock is thought to have been blasted off Mars by an asteroid strike and later landed on Earth. ALH84001 caused excitement when it was discovered to contain carbonate globules associated with water. Inside the globules are large organic molecules that look like fossilized bacteria.
Schulze-Makuch says the idea that there was life in the meteorite is still being debated but one thing is certain: its interior was only heated to about 40 degrees Celsius. “So, if there were living organisms inside, they could’ve survived. They could’ve just gone dormant. Life can survive space travel,” he says.
The speculation among some of his colleagues is that life originated on Mars and was seeded onto Earth by an asteroid strike.
Schulze-Makuch points out that early on, conditions for life were much more favorable on Mars than Earth. “Mars had oceans—or at least liquid water and an atmosphere,” he says. Earth was recovering from “a collision with a huge object that tore off a piece of the planet and formed the moon.” He says Earth was also probably covered with magma at the time, prohibiting the establishment of any kind of life.
WSU professor of geology Jeffrey Vervoort doubts some of those ideas. Indeed, scientific theories, hypotheses, and speculation vary widely among those studying the new frontiers of space. But Vervoort has faith in this: He’s pinpointed the age of the solar system at 4.567 billion years using the most common type of meteorites, the stony chondrites.
I walk across campus one cold blustery afternoon to talk with him in his Webster office next door to Nick Foit.
Vervoort is a soft-spoken historian of the solar system. He is also a type of cosmochemist, in that he uses chemistry to study objects from space. It turns out that it’s easier to calculate the age of the solar system than it is our own planet Earth.
“Earth is such a dynamic planet with volcanoes and tectonic plates moving across its surface,” he says. “The whole planet has been processed and melted—there are no vestiges of the original materials left to study. There is nothing we can put our hands on to directly determine the age of the Earth.”
“This is the closest we can come,” Vervoort says as he retrieves a pink, quartz-like rock that came from Australia. Shimmering slightly, the stone is full of minute zircons, whose tiny forms have been dated to 4.4 billion years, the oldest known minerals on the planet. But the surrounding rock is much younger.
“We need another way to age the Earth,” he says. “That’s where the meteorites come in.”
Vervoort explains that our solar system was born from a cloud of interstellar dust and hydrogen gas that collapsed and began rotating as the result of a nearby supernova. Gravity eventually swept most of the material into the center to form the sun. The outer material gave rise to the different planets, moons, and asteroids. The rocky terrestrial planets—Mercury, Venus, Earth, and Mars—formed closest to the sun while the more volatile gas and ice giants—Saturn, Jupiter, Uranus, and Neptune—formed farther away.
A ring of leftover remnants orbiting between Mars and Jupiter became known as the Main Asteroid Belt. A second ring beyond Neptune, the Kuiper Belt, contains the dwarf planet Pluto as well as asteroids of highly elliptical orbits that cut across the solar system. And, in the outermost reaches of the solar system lies the spherical Oort Cloud, home to potentially trillions of icy objects including the comets that periodically pass near Earth.
Vervoort says that most of the iron and stony meteorites that fall to Earth come from the Main Belt and are representative of the terrestrial planets. These meteorites vary widely in composition but for his research, Vervoort focuses on a class of stony chondrites.
“They are really quite interesting,” he says. “The most primitive ones appear almost fluffy and you can nearly break them apart with your hands even though they’ve been flying around the solar system for 4.5 billion years.”
To determine the age of the chondrites, Vervoort and graduate student Audrey Bouvier analyzed the radioactive decay of uranium into lead for different components of the meteorites.
“Uranium is naturally occurring in all meteorites and in virtually all rocks,” he says. “We know that it decays down to certain isotopes of lead with very precise half lives. So we measure the ratio of uranium to lead and can determine the specific age of a rock; in this case, the oldest components of chondrites are 4.567 billion years.
“So, we know the Earth is younger than 4.567 billion years and older than 4.4 billion years,” Vervoort says. Using indirect evidence plus data from other researchers, he estimates our blue planet was largely formed between 4.53 and 4.52 billion years ago.
“Trying to understand how the Earth and solar system formed is one of the most fascinating things in all of human knowledge,” says Vervoort. “Our solar system is but one among billions of galaxies each with millions of solar systems. We don’t often think about how absolutely enormous the known universe is.”
WSU astrophysicist Guy Worthey has spent a lifetime dreaming about it.
An associate professor in the department of physics and astronomy, Worthey reaches beyond the solar system to study galaxies and the origin of chemical elements like carbon. He can also tell you a lot about red giant and cool dwarf stars.
This gray January day, I’m waiting as he attends to a whistling tea pot in the other room. Gregarious with a wry sense of humor, Worthey admits to a fascination with menacing tales of asteroids, and especially likes the story of Ann Hodges from Sylacauga, Alabama. On November 30, 1954, Hodges was napping on her couch when an 8-pound meteorite crashed through her roof, bounced off a radio, and slammed into her hip, causing severe bruising. It was the first documented meteorite to hit a U.S. citizen and drew extensive publicity.
An icy jigsaw puzzle
Jupiter’s frosty moon Europa is quite a celebrity. Photos taken by the NASA Galileo spacecraft in the early 2000s showed curious cracks and ridges on the moon’s icy shell along with hints of a watery ocean below. In 2014, planetary geologists Simon Kattenhorn from University of Idaho and Louise Prockter of Johns Hopkins University discovered apparent signs of plate tectonics operating on Europa.
“It’s exciting,” WSU associate professor of geology Katie Cooper says. “It’s one of the biggest recent solar system discoveries and there was even a question about it on Jeopardy last summer.”
Cooper is a geodynamicist widely recognized for her research on the motion of the Earth’s crust and mantle via plate tectonics, volcanoes, mountain building, and other processes.
Now Cooper has teamed up with Prockter under a grant from the NASA Solar System Working Program to document plate tectonic behavior on Europa. Cooper is developing computer models of Europa’s icy brittle plates and other surface features to determine if geologic processes such as subduction are present. If successful, it will be the first complete characterization of plate tectonics on ice, she says.
It would also make Europa the only other body in the solar system, besides Earth, to exhibit plate tectonics. And with a vast ocean of water just below the ice shell, the moon is one of the solar system’s most promising places to search for life.
Though that rock was relatively small, Worthey says it’s inevitable one of the much larger near-Earth asteroids will eventually hit our planet unless we do something to stop it. NASA’s Asteroid Redirect Mission (ARM) is a step in that direction. ARM is a part of the broader Asteroid Initiative which seeks to identify potentially dangerous asteroids and prevent them from striking Earth. The goal of ARM is to capture an asteroid and bring it back to the moon.
When the initial call for ideas went out, California-based aerospace company Airborne Systems responded with a proposal to “snag a free-floating asteroid, haul it back toward Earth, and put it into orbit around the moon,” says Gilbert Dodgen ’74, ’77 MA Music *.
Dodgen, a software engineer with Airborne Systems, designs computer models of various spacecraft systems, including the asteroid-capturing device. For that project, he modeled cylindrical fabric beams that are extremely durable when inflated. He says the finished beams were bound into a hand-like contraption that could “grab” a suitable asteroid.
“The idea was that a spacecraft would go out and deploy the air beams with a bag attached. It would slowly come up to the asteroid, pass the bag around it, then deflate the beams to hold it in place. The spacecraft would then tow the asteroid back to the lunar orbit where it would remain permanently for astronauts to study,” he says.
But NASA had a second option—a rival company proposed sending a probe to pluck a small asteroid off the surface of a large asteroid, and in 2015, NASA chose that plan.
Ultimately, these projects play into the larger goal of developing technologies for a human mission to Mars. Today Dodgen is part of a team devising inflatable deceleration systems to help spacecraft land safely on the red planet. The thin atmosphere on Mars requires rockets to brake more quickly than when entering Earth’s atmosphere or risk a crash. His current designs include a supersonic jellyfish-like parachute.
Worthey would jump at the chance to travel to another planet and suggests, in the long run, that we terraform both Mars and the moon. Terraforming is the process of turning barren, hostile environments into habitable ones.
For starters, Worthey says there are many comets, Kuiper Belt objects, and little moons like Europa and Ganymede in the outer solar system that are full of water. They also have low gravitational fields making them accessible for water mining. Since today’s chemical rockets use the ingredients for water—liquid oxygen and hydrogen —he proposes we use some of these bodies for fuel as well as terraforming.
He envisions sending robot-operated rockets to capture an icy moonlet and jet it back to our own moon. As the ice disintegrated, it would create lunar water and a thick atmosphere. “Eventually, we could move in,” he says.
“This is technically feasible now,” Worthey says. “We don’t need fusion or antimatter; we just need the willpower. It’s possible to send robots to places like a comet, icy asteroid, or maybe some of Saturn’s ring system particles where they could mine water. Then as the rocket thrusts its way back through the solar system it could consume some of that water as fuel.”
No longer confined to the realm of science fiction, terraforming has become a vibrant area of research especially as it applies to Mars. But before scientists can terraform the red planet, they must determine what drove Mars into its current desolate state. To that end, NASA’s Mars Exploration rovers are on the ground, busily searching for clues of past geological processes and water activity.
There are also plans to terraform the moon. The concept, says NASA, is to place mobile robotic mirrors, called TransFormers, at the rim of a freezing lunar crater. The mirrors would be angled to reflect sunlight down into the crater, providing light, warmth, and solar energy for robots and eventually human explorers.
Full of optimism, Worthey says, “I would love to see us on a green moon and green Mars exploring nearby stars. In the Milky Way galaxy there are at least three billion habitable planets—basically Earth twins in the same place in their solar systems as Earth is. When fusion is physically possible, it will pan out. If we have the willpower it will happen quickly.”
Afterword: Soon after this article was published, we received the sad news that Gilbert Dodgen ’74, ’77 MA passed away on Sunday, April 24, 2016, at his home in Trabuco Canyon, California. Our thoughts are with his family.
Infographic
Explore the asteroid belt and near Earth objects
Web extras
Colonizing the stars
WSU students designed a 3-D printed habitat for Mars.
Perchance to dream
Astronomer Guy Worthey, star parties, and the promise of space
On the web
Asteroid Grand Challenge: A NASA program encouraging amateur astronomers and others to help watch the skies for any potentially undetected Near Earth Objects
Space probe finds 72 new objects near Earth (CNN, April 7, 2016)
Awesome photo of Comet 67P: Lessons from the Rosetta mission (Christian Science Monitor, April 2, 2016)
Iron Meteorites Play Hide-and-Seek Under Antarctic Ice (Smithsonian.com, February 16, 2016)
Beautiful Photos of Impact Craters—Where Space Rocks Met Earth (mental_floss)
2015 Was the Best Year Ever in Space (by David Brin, Nautilus, January 7, 2016)
What Meteorites Mean for Science, Culture, and Kitsch (National Geographic, December 27, 2015)