In 1898, Marie and Pierre Curie discovered radium. Claimed to have restorative properties, radium was added to toothpaste, medicine, water, and food. A glowing, luminous green, it was also used in beauty products and jewelry. It wasn’t until the mid-20th century we realized that radium’s harmful effects as a radioactive element outweighed its visual benefits.
Unfortunately, radium isn’t the only pigment that historically seemed harmless or useful but turned out to be deadly. That lamentable distinction includes a trio of colors and pigments that we’ve long used to decorate ourselves and the things we make: white, green, and orange.
The biggest obstacles a human would encounter living on the moon is cosmic radiation. Unlike the Earth, the moon has no atmosphere and no magnetic field. A person on its surface could receive over 400 times the maximum safe dosage of heavy ion radiation, enough to be fatal within ten hours, even in a spacesuit.
Many of us will experience some kind of trauma during our lifetime. Sometimes, we escape with no long-term effects. But for millions of people, those experiences linger, causing symptoms like flashbacks, nightmares, and negative thoughts that interfere with everyday life.
This phenomenon, called post-traumatic stress disorder, or PTSD, isn’t a personal failing; rather, it’s a treatable malfunction of certain biological mechanisms that allow us to cope with dangerous experiences.
PTSD has been called “the hidden wound” because it comes without outward physical signs. But even if it’s an invisible disorder, it doesn’t have to be a silent one.
On the night of January 1, 1801, Giuseppe Piazzi, a priest in Palermo, Italy, was mapping the stars in the sky. Over three nights, he’d look at and draw the same set of stars, carefully measuring their relative positions.
That night, he measured the stars. The next night, he measured them again. To his surprise, one had moved. The third night, the peculiar star had moved again. This meant it couldn’t be a star at all.
It was something new, the first asteroid ever discovered, which Piazzi eventually named Ceres. Asteroids are bits of rock and metal that orbit the Sun. At over 900 kilometers across, Ceres is a very large asteroid. But through a telescope, like Piazzi’s, Ceres looked like a pinpoint of light similar to a star. In fact, the word asteroid means star-like. You can tell the difference between stars and asteroids by the way they move across the sky. Of course, Piazzi knew none of that at the time, just that he had discovered something new. To learn about Ceres, Piazzi needed to track its motion across the sky and then calculate its orbit around the Sun.
So each clear night, Piazzi trained his telescope to the heavens. Night after night, he made careful measurements, but from his observations he learned that Ceres was only visible in the sky during the day. It would take another year and a lot of astronomers to nail down Ceres’ path, but we haven’t lost track of it since.
Today, we can do something that Piazzi could only dream of: send spacecraft to study asteroids up close. One spacecraft called Dawn journeyed billions of kilometers over four years to the main asteroid belt. There, it visited Ceres and another asteroid, Vesta. Dawn’s stunning images transformed Piazzi’s dot of light into a spectacular landscape of craters, landslides, and mountains.
In 1997 in a game between France and Brazil, a young Brazilian player named Roberto Carlos set up for a 35 meter free kick. With no direct line to the goal, Carlos decided to attempt the seemingly impossible. His kick sent the ball flying wide of the players, but just before going out of bounds it hooked to the left and soared into the goal.
According to Newton’s first law of motion, an object will move in the same direction and velocity until a force is applied on it. When Carlos kicked the ball he gave it direction and velocity, but what force made the ball swerve and score one of the most magnificent goals in the history of the sport?
The trick was in the spin. Carlos placed his kick at the lower right corner of the ball, sending it high and to the right, but also rotating around its axis.
The ball started its flight in an apparently direct route, with air flowing on both sides and slowing it down. On one side, the air moved in the opposite direction to the ball’s spin, causing increased pressure, while on the other side—the air moved in the same direction as the spin, creating an area of lower pressure.
That difference made the ball curve towards the lower pressure zone. This phenomenon is called the Magnus effect.
This type of kick, often referred to as a banana kick, is attempted regularly, and it is one of the elements that makes “The beautiful game” beautiful.
But curving the ball with the precision needed to both bend around the wall, and back into the goal is difficult. Too high and it soars over the goal. Too low and it hits the ground before curving. Too wide and it never reaches the goal.
Not wide enough and the defenders intercept it. Too slow and it hooks too early or not at all. Too fast and it hooks too late.
The same physics make it possible to score another apparently impossible goal—an unassisted corner kick.
The Magnus effect was first documented by Sir Isaac Newton after he noticed it while playing a game of Tennis back in 1670. It also applies to golf balls, Frisbees and baseballs. In every case the same thing happens: the ball’s spin creates a pressure differential in the surrounding airflow that curves it in the direction of the spin.
And here’s a question: could you theoretically kick a ball hard enough to make it boomerang all the way around back to you? Sadly, no. Even if the ball didn’t disintegrate on impact or hit any obstacles, as the air slowed it, the angle of its deflection would increase, causing it to spiral into smaller and smaller circles until finally stopping. And just to get that spiral you’d have to make the ball spin over 15 times faster than Carlos’s immortal kick. So good luck with that.
If you lived on the moon, you’d have to exercise for hours a day to maintain bone and muscle mass. That’s because the moon’s gravity is just one-sixth that of the Earth, and the everyday strain of working against gravity is part of what keeps our bodies healthy.
As of 1989, mankind had successfully sent craft to every known planet in the solar system except one—Pluto.
You may have heard that astronomers don’t consider Pluto or its brethren to be planets. However, most planetary scientists still do, which is why we’re using that terminology here. There’s a limited amount we can learn about Pluto from Earth because it’s so far from us.
Pluto, however, is a scientific goldmine. It’s located in a region called the Kuiper Belt, home to many small planets, hundreds of thousands of ancient icy objects, and trillions of comets. This mysterious region holds clues to the formation of our solar system, and it was long, tantalizingly beyond our reach.
Until New Horizons. Its objectives: explore Pluto, collect as much scientific data as possible, transmit it back to Earth, then explore farther out in the Kuiper Belt. To achieve this, the New Horizons team outfitted their craft with seven state-of-the-art scientific instruments.
To see how New Horizons got to Pluto in time, let’s jump to its launch. Its three rocket stages accelerated New Horizons to such great speeds that it crossed the 400,000 kilometers to the moon in just nine hours. About a year later, the craft reached Jupiter and got what’s called a gravity assist. That’s where it flies close enough to the gas giant to receive a gravitational slingshot effect. New Horizons was then flying at around 50,000 kilometers per hour, as it would for the next eight years to cross the remaining gulf to Pluto.
Going at such an astonishing speed meant that slowing down to get into orbit or land would’ve been impossible. That’s why New Horizons was on a flyby mission, where it would get just one chance to scream by Pluto and make its observations. The flyby would have to be fully automated, since at that distance, any signals to guide it from Earth would take 4.5 hours to reach it. So the team loaded the ship’s computer with a series of thousands of commands, called the core load, that would begin to execute when the craft was 6.5 days from Pluto. But when New Horizons was just ten days out, disaster almost struck. Ground control lost contact with the spacecraft. After two nerve-wracking hours, New Horizons came back online, but mission control discovered that its main computer had rebooted, losing the entire core load and other critical data. Without that, it would soon whizz by Pluto with virtually nothing to show for the mission. Alice Bowman, the mission’s Operations Manager, led a team for 72 sleepless hours to get the instructions loaded back into New Horizons in time. Without room for a single error, she and her team pulled it off, and New Horizons began taking and broadcasting breathtaking images. Those observations have revealed a delightfully varied world, with ground fogs, high altitude hazes, possible clouds, canyons, towering mountains, faults, craters, polar caps, glaciers, apparent dune fields, suspected ice volcanoes, evidence for past flowing liquids, and more.
The exploration of Pluto was a great success, but New Horizons isn’t done yet. On January 1, 2019, it’ll break its own record for furthest explored object when it visits a Kuiper Belt Object called 2014 MU69, which is orbiting the sun another billion kilometers farther away than Pluto. The world is holding its breath to see what it’ll find there.
Dust lives right under our noses, but from our perspective, the tiny specks of brilliant color blend together into a nondescript grey. What are these colorful microscopic particles?
What distinguishes the dust in your house from, say, sand on a beach is that it is a mixture of many different ingredients. It can contain grains of sand, dead skin cells, tiny hairs and threads, animal dander, pollen, manmade pollutants, minerals from outer space, and, of course, dust mites.
We shed dead skin cells constantly, and wherever we live, they mix into the household dust. The same goes for our pets: their dander and hairs enter the mix, as do tiny pieces of thread and cotton fibers from our clothes. These components make every household’s dust a unique blend of bits from its particular inhabitants. Household dust also contains substances that blow in from the wider world. Depending on the local geology, finely ground quartz, coal, or volcanic ash might enter the air as atmospheric dust, along with pollen and fungal spores. Industrial activities also contribute cement powder, particles from car tires, and other chemicals to the airborne mix.
In addition to markers of humans, animals, and landscapes, dust also contains particles from further afield. When a star explodes in a distant galaxy, super hot gases vaporize everything nearby. Then, the dust settles; minerals condense out of the gas. Floating out there between planets and galaxies, this extraterrestrial dust contains tiny pieces of extinguished stars and the building blocks of future celestial bodies. Every year, tens of thousands of tons of cosmic dust lands on Earth and mingles with terrestrial minerals. This blend of chemicals, minerals, and intergalactic particles settles out of the air onto surfaces in our homes, mixing with the detritus of each house’s occupants. Stars explode, mountains erode, and buildings, plants, and animals are all slowly but surely pulverized into fine grey powder.
We’re all destined to become dust, but it’s also possible that we came from it. Interstellar dust has been found to carry organic compounds through space. It’s possible that billions of years ago, some of these cosmic particles were the seed of life on our little blue planet.