from the world's big
NASA astronaut drops mirror during spacewalk outside ISS
Watch as the small mirror joins millions of other pieces of space junk currently orbiting the planet.
- The incident occurred while astronauts were servicing the International Space Station during a scheduled spacewalk.
- The spacewalk was successful and NASA said the mirror poses no immediate danger to the station.
- Space debris remains a big problem for space agencies worldwide.
An astronaut dropped a small mirror during a spacewalk on Friday outside of the International Space Station (ISS), adding to the millions of pieces of space debris currently orbiting the planet.
ISS Space Station Commander Chris Cassidy and NASA astronaut Bob Behnken were upgrading the station's power system, replacing old batteries during one of four scheduled spacewalks, when a 5-inch by 3-inch mirror came loose from Cassidy's spacesuit. Astronauts wear small wrist mirrors on the sleeves of their spacesuits to help them see, in part because their helmets limit field of view.
It was dark when the mirror came loose. Cassidy later said he didn't find any damage when he later inspected his suit in the light, according to The Associated Press. The rest of the six-hour spacewalk was successful and NASA said the 0.1-pound mirror poses no danger to the space station.
One mirror may not cause much trouble, but the millions of pieces of space debris orbiting Earth pose a perennial threat to all space missions. NASA has catalogued more than 20,000 pieces of man-made space junk bigger than a softball, ranging from abandoned launch vehicle stages to fragments leftover from collisions between spacecraft.
"They travel at speeds up to 17,500 mph, fast enough for a relatively small piece of orbital debris to damage a satellite or a spacecraft," NASA wrote in a blog post. "There are 500,000 pieces of debris the size of a marble or larger. There are many millions of pieces of debris that are so small they can't be tracked."
The small, untraceable pieces of space junk — both natural and man-made — are especially dangerous.
"Even tiny paint flecks can damage a spacecraft when traveling at these velocities," NASA wrote. "In fact a number of space shuttle windows have been replaced because of damage caused by material that was analyzed and shown to be paint flecks."
To get an idea of how much damage a tiny piece of debris can do at super-high speeds, check out the photo below of what a 0.03-pound piece of plastic did to a block of aluminum. Conducted using a light-gas gun, the pea-sized fragment left a crater in the block that's about 5 inches deep.
Space junk isn't a new problem. NASA, for example, has been researching strategies to reduce the amount of space junk orbiting Earth since founding its Orbital Debris Program in 1979. The bulk of space junk exists in low Earth orbit, which the space community views as the "world's largest garbage dump," according to NASA.
What's worse, the dangers of space debris increase as each new object is added to orbit. This is described by the Kessler Syndrome, which is the case where "two colliding objects in space generate more debris that then collides with other objects, creating even more shrapnel and litter until the entirety of LEO is an impassable array of super swift stuff. At that point, any entering satellite would face unprecedented risks of headfirst bombardment."
Perhaps surprisingly, there are no international laws that explicitly require countries to remove or avoid adding space debris, but the Outer Space Treaty — of which 110 countries are party — notes that space agencies should avoid the "harmful contamination" of outer space. Still, space agencies and researchers have recently been exploring new ways to actively remove space junk from orbit.
One potential solution involves using small satellites — cubesats — to hunt down and deorbit space junk using nets and tethers. Called OSCaR (Obsolete Spacecraft Capture and Removal), the satellites would be transported into orbit aboard larger spacecraft, and then would find and remove space junk mostly autonomously.
"We tell OSCaR what to do and then we have to trust it," project leader Kurt Anderson, a professor of mechanical, aerospace and nuclear engineering at Rensselaer Polytechnic Institute in New York, said in a statement. "That's why this problem actually gets very hard, because we are doing things that a big, expensive satellite would do, but in a CubeSat platform."
Sallie Krawcheck and Bob Kulhan will be talking money, jobs, and how the pandemic will disproportionally affect women's finances.
What would it be like to experience the 4th dimension?
Physicists have understood at least theoretically, that there may be higher dimensions, besides our normal three. The first clue came in 1905 when Einstein developed his theory of special relativity. Of course, by dimensions we’re talking about length, width, and height. Generally speaking, when we talk about a fourth dimension, it’s considered space-time. But here, physicists mean a spatial dimension beyond the normal three, not a parallel universe, as such dimensions are mistaken for in popular sci-fi shows.
Health officials in China reported that a man was infected with bubonic plague, the infectious disease that caused the Black Death.
- The case was reported in the city of Bayannur, which has issued a level-three plague prevention warning.
- Modern antibiotics can effectively treat bubonic plague, which spreads mainly by fleas.
- Chinese health officials are also monitoring a newly discovered type of swine flu that has the potential to develop into a pandemic virus.
Bacteria under microscope
needpix.com<p>Today, bubonic plague can be treated effectively with antibiotics.</p><p style="margin-left: 20px;">"Unlike in the 14th century, we now have an understanding of how this disease is transmitted," Dr. Shanthi Kappagoda, an infectious disease physician at Stanford Health Care, told <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">Healthline</a>. "We know how to prevent it — avoid handling sick or dead animals in areas where there is transmission. We are also able to treat patients who are infected with effective antibiotics, and can give antibiotics to people who may have been exposed to the bacteria [and] prevent them [from] getting sick."</p>
This plague patient is displaying a swollen, ruptured inguinal lymph node, or buboe.
Centers for Disease Control and Prevention<p>Still, hundreds of people develop bubonic plague every year. In the U.S., a handful of cases occur annually, particularly in New Mexico, Arizona and Colorado, <a href="https://www.cdc.gov/plague/faq/index.html" target="_blank">where habitats allow the bacteria to spread more easily among wild rodent populations</a>. But these cases are very rare, mainly because you need to be in close contact with rodents in order to get infected. And though plague can spread from human to human, this <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">only occurs with pneumonic plague</a>, and transmission is also rare.</p>
A new swine flu in China<p>Last week, researchers in China also reported another public health concern: a new virus that has "all the essential hallmarks" of a pandemic virus.<br></p><p>In a paper published in the <a href="https://www.pnas.org/content/early/2020/06/23/1921186117" target="_blank">Proceedings of the National Academy of Sciences</a>, researchers say the virus was discovered in pigs in China, and it descended from the H1N1 virus, commonly called "swine flu." That virus was able to transmit from human to human, and it killed an estimated 151,700 to 575,400 people worldwide from 2009 to 2010, according to the Centers for Disease Control and Prevention.</p>There's no evidence showing that the new virus can spread from person to person. But the researchers did find that 10 percent of swine workers had been infected by the virus, called G4 reassortant EA H1N1. This level of infectivity raises concerns, because it "greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses," the researchers wrote.
The word "learning" opens up space for more people, places, and ideas.
- The terms 'education' and 'learning' are often used interchangeably, but there is a cultural connotation to the former that can be limiting. Education naturally links to schooling, which is only one form of learning.
- Gregg Behr, founder and co-chair of Remake Learning, believes that this small word shift opens up the possibilities in terms of how and where learning can happen. It also becomes a more inclusive practice, welcoming in a larger, more diverse group of thinkers.
- Post-COVID, the way we think about what learning looks like will inevitably change, so it's crucial to adjust and begin building the necessary support systems today.