DiscoverMay 2019的目錄

OK, I realize I’m more than 20 years late to the party, but I’m finally catching up on Star Trek: Voyager. In it, Capt. Kathryn Janeway commands her crew as the far-flung starship claws its way back to Earth. Invariably, when you travel across star systems hundreds of years in the future, you’ll come across bizarre nebulas and Earth-like planets that make you homesick. But one factoid mentioned in passing in the show’s dialogue stuck in my brain: Earthlings had colonized Mars by 2100. Huh, I wonder how the Martian immigrants thrived? They must have cracked the mystery of how to have kids in space — not an easy feat. As you’ll read in one story in our special report on the future of fertility, we have a long way…

WATER AND WIND CAN BE TRICKSTERS. Over time, these erosional forces can sculpt rocks, shells and other natural materials into shapes that appear to be the work of human hands (or of those of our evolutionary ancestors). Sometimes amateurs and archaeologists alike mistake these geofacts — a mashup of geology and artifact — for stone tools, projectile points and even figurative art. Fortunately, science has tools to determine whether the object was fabricated, or just a fluke. And that’s a fact.…

Beyond the protection of Earth’s atmosphere, Martian residents will be pelted with dangerous, high-energy radiation. It blazes from our sun during fiery solar flares, and is also thought to blast from distant supernova explosions. These cosmic rays are made up of atomic nuclei (protons and neutrons) and electrons, which get knocked out of the atoms as they fly through space at nearly the speed of light. After the electrons are gone, the remaining particles become ionized, ready to transfer energy to nearby objects. This powerful radiation can penetrate a spacecraft or an astronaut’s body without pause. When it comes in contact with humans, the rays can wipe out the electrons in their cells. This bombardment is known to damage the structure of DNA and cause cells to mutate or die off altogether,…

Oh leave the Wise our measures to collate One thing at least is certain, LIGHT has WEIGHT, One thing is certain, and the rest debate — Light-rays, when near the Sun, DO NOT GO STRAIGHT.…

Relativity makes numerous bizarre predictions, many of them experimentally verified. They only seem bizarre because we don’t notice them in our daily lives — we live, for the most part, in Newton’s reality. But beyond that lies Einstein’s universe, where gravity bends space and time to its will. Here are some of the theory’s strangest side effects: * Gravity literally slows down time. Waves of light emitted by stars stretch out because of this time bending, and objects closer to a massive object age more slowly. Super-precise clocks, which tick according to the vibrations of atoms, have verified that gravity alters time’s flow. * Satellites have shown that rotating celestial bodies twirl the fabric of the cosmos around themselves, like honey twisted by a spoon, affecting the motion of gyroscopes.…

The term “gluten-free” seems to be everywhere these days: food labels, restaurant menus, cookbooks, even water bottles. While it’s become trendy to avoid gluten — a protein found in popular foodstuffs like bread and pasta — humans have safely and enthusiastically consumed it for thousands of years. Food containing gluten remains a staple of the human diet around the world, providing sustenance to billions. People with celiac disease can literally starve to death in the presence of food. So why this apparent backlash against gluten? While the protein is a vital part of the human diet, for some people, it really is unsafe. The path to this seemingly simple discovery was long and tortuous, dating back to a particularly bleak period of World War II. Holland was suffering in the…

Alzheimer’s Annihilation (“Alzheimer’s Under Attack,” December 2018) Of all the subjects that you have covered, your article on Alzheimer’s is by the far the most important. Since I have a long family history of the disease, I probably would be in its throes if I hadn’t eliminated the risk factors as examined in the article. I can’t do anything about my genetic predisposition to Alzheimer’s. And that’s why, at 81, I only just retired from being a college adjunct and have kept my mind active and challenged. William C. Weckerly Minneola, Fla. The Clock Is Ticking (“The State of Science: Policy,” January/February 2019) You questioned the impact that the “right to try” bill would have, since the FDA already has a program called “expanded access,” which allows patients to request…

EARLY IN THE 20TH CENTURY, a strange tomato plant took root in the northeastern United States. Because of a random genetic mutation, the plant’s branches were shorter than normal. The result was a more compact crop that was easier to harvest. “Breeders started using it,” says Joyce Van Eck, a plant biologist with Boyce Thompson Institute in New York. “Over time, the trait revolutionized commercial tomato production.” Most other qualities we associate with tomatoes also arose by chance. Over millennia of selective breeding, the fruit grew from the size of a pea to that of an apple, and ripening was streamlined to ensure supermarket tomatoes were uniformly red. The farmers who had laid claim to these desirable traits inadvertently lost others, such as flavor, nutritional value and drought resistance —…

At Discover, we focus on the scientific advances that will shape tomorrow’s world. So it’s only natural that we dive into the most fundamental way humans create the future: reproduction. Our society is in the middle of a potential watershed moment for what’s been, until recent history, the most primal of processes. New technologies are making it increasingly possible to intervene in the creation of human life. Whether this entails altering an embryo’s DNA before it’s born or using genetic information to assess potential mates, we have the tools to mold future generations more explicitly than ever before. This power brings new responsibilities and ethical worries. We need look only to history and science fiction to see the potential pitfalls of gene editing, artificial gestation and more. Still, these technologies…

Tay-Sachs is a recessive genetic disease. That means, for the disease to manifest, both copies of a gene must have the Tay-Sachs mutation. Some people can be carriers for the disease: They have one mutated copy, but their second copy is healthy and dictates how that gene is expressed. But if two carriers have a child, there’s a chance the child could inherit both mutated copies from their parents and could end up with the disease. In some communities of Ashkenazi Jews, who are at a higher risk for the disease, there’s already a variation of genetic matchmaking to prevent cases of Tay-Sachs.…

Earth and Mars might be neighbors, but conditions on the two worlds differ drastically. Humans are accustomed to Earth’s abundant sunshine, hefty gravity and the protection of our atmosphere and magnetic field. The Red Planet, on the other hand, has frigid temperatures, a mere fraction of Earth’s gravity and is not protected from hazardous radiation. When stacked up, life on Mars might make you rethink your dream of becoming an astronaut. GRAVITY 2.66 times that of Mars 0.375 times that of Earth AVERAGE DISTANCE FROM SUN 92,955,820 miles 142,633,260 miles AVERAGE SURFACE TEMPERATURE 57 degrees F -81 degrees F WATER COMPOSITION Abundant, flowing water on both the surface and below. Water vapor is prevalent in the atmosphere, and water ice exists in frozen regions. Water ice exists on the surface…

Exoplanets, nowadays, are commonplace. Impossibly hot gas giants, rocky super-Earths and prolific seven-planet systems have captivated scientists and the public alike. So it may be hard to remember only 30 years ago, when every new claim of a world outside the solar system was revolutionary and met with disbelief. In that uncertain era, one massive object danced along the boundary between planets and stars. The astronomers who discovered the object played it safe and classified their newfound world, dubbed HD 114762b, as an obscure type of pseudo-star. A few years later, astronomers discovered two worlds orbiting another star, a pulsar named PSR 1257+12, and that was that — the era of uncertainty was over and the first exoplanets had been found, destined for the history books. But what if that…

The Biggest Step Yet Genetically modified organisms, or GMOs, can be a touchy subject. People who champion the use of genetic engineering in produce argue that it can yield crops that are potentially more resistant to pests and droughts, and can boast better nutritional value. Others counter that genetic tinkering could introduce unintended, harmful consequences to the environment and humans. Now that the USDA will begin requiring food manufacturers to roll out GMO labeling in 2020, we asked our readers on Facebook for their thoughts on the polarizing subject. Windy Lee I’m against GMOs and fully support labeling. We have a right to know what we’re eating. Do you support GMO labeling requirements for food? YES 33% NO 67% Angela Christine Jones I support labeling only if we are going…

Mars is a cold, dry place where liquid water appears only fleetingly. But caches of water ice exist: In the northern lowlands, Korolev Crater holds an enormous reservoir over a mile thick in places. This photograph from the European Space Agency combines five different images to reveal the 51-mile-wide crater and its ever-present ice. Unlike other, more temporary ice deposits on the planet, Korolev is expansive enough that the thin Martian air settles over it and creates a chilly layer that acts as a cooling shield, keeping the crater continuously icy. This photo comes from the Mars Express orbiter, which has been snapping pictures since it first started circling the Red Planet in 2003.…

As she lay on her back on the exam table, I felt her abdomen and located a mass just above her right hip, toward her back. Life was changing fast for Ameera. She had moved with her family thousands of miles from the Middle East to Canada, and had just started school as a sixth-grader. The 11-year-old was excited but also anxious, and she started to complain of stomach pain. Eventually her parents took her to their family doctor. During the exam, the doctor discovered that Ameera’s blood pressure was higher than it should have been for her age. So, she ordered an ultrasound of her kidneys, since they help regulate blood pressure. The test revealed she had a mass near her right kidney, and she was referred to the…

The main takeaways behind Einstein’s general theory of relativity: 1 Time and space are neither flat nor fixed; they are curved and distorted by mass and energy. 2 Gravity is not a force, but rather a distortion of time and space. 3 The effects of gravity are indistinguishable from the effects of acceleration, over a small space. EINSTEIN’S INSPIRATION FOR GENERAL RELATIVITY STRUCK WHILE HE WAS A PATENT CLERK IN SWITZERLAND IN 1907. why a clock on a satellite ticks a few dozen microseconds faster than a clock on Earth; without accounting for that discrepancy, GPS technologies wouldn’t work.…

“Who are you?” I ask. “Cortana,” replies the cheerful female voice coming out of my phone. “I’m your personal assistant.” “Tell me about yourself,” I say to the Microsoft AI. “Well, in my spare time I enjoy studying the marvels of life. And Zumba.” “Where do you come from?” “I was made by minds across the planet.” That’s a dodge, but I let it pass. “How old are you?” “Well, my birthday is April 2, 2014, so I’m really a spring chicken. Except I’m not a chicken.” Almost unwillingly, I smile. So this is technology today: An object comes to life. It speaks, sharing its origin story, artistic preferences and corny jokes. It asserts its selfhood by using the first-person pronoun “I.” When Cortana lets us know that she is…