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12 Cool Experiments Done on the International Space Station

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As an orbiting laboratory, the International Space Station (ISS) offers researchers around the world the unique opportunity to perform experiments in microgravity and under the rigors of the space environment. Scientists have used the station for everything from testing technology for future space exploration to studying human health. Sometimes their work involves some pretty unusual experiments. Here are 12 cool ones. 

1. Headless flatworms

On Earth, flatworms can regenerate their own cells, replacing them as they age or are damaged. Scientists cut the heads or tails off of flatworms and sent them to the station in September 2014 to study whether the cell signaling mechanisms behind this regeneration work the same way in space as they do on Earth.  The results should provide insight into how gravity affects tissue regeneration and the rebuilding of damaged organs and nerves, which is important for understanding how wounds heal—both in space and on the ground.

2. Space mice

For humans to explore deep space or live on other planets, we must learn how to deal with the effects of long-term exposure to potent space radiation, which can cause cancer and gene mutations, affecting subsequent generations. Lab mice are important tools for studying radiation effects, but currently, mice can’t go to the station. So instead, this investigation will send frozen mouse embryos for a ride in space and implant them into surrogate mothers on their return to Earth. Scientists will use these space mice to study longevity, cancer development, and gene mutations.

3. Talking Zucchini

In 2012, Astronaut Don Pettit wrote blog posts on behalf of a zucchini plant that was grown from a seed on the space station, one of many investigations on growing greenery in space. The ultimate goal is using plants to provide oxygen and fresh produce for crews on long-term space missions. Gravity plays an important role in normal plant growth and development, though, and not only is gravity nearly nonexistent in space, but plants also are affected by radiation, changes in light, and other factors of the space environment. The anthropomorphic Zucchini and its blog were a way to engage students with space-based research and encourage the next generation of space station scientists.

4. Putting out the fire

Fire behaves differently in space, thanks to complicated interactions of fuel vaporization, radiative heat loss, and chemical kinetics. Effectively extinguishing flames in space depends on understanding those interactions. This investigation, performed earlier this month, tested various fire suppressants in microgravity. Researchers found that flames in space burn with a lower temperature, at a slower rate, and with less oxygen than in normal gravity, meaning higher concentrations of materials must be used to put them out. The most surprising discovery was the way heptane droplets seemed to continue to burn under certain conditions even after the initial fire was extinguished. This phenomenon is called "cool-flame extinction." Those who understand conventional theories of droplet combustion say those theories don’t explain this behavior, making the cool flames a unique observation with significant theoretical and practical implications.

5. ISS, Robot

This two-armed humanoid robot torso mounted in the station can manipulate hardware and work in high risk environments to give crewmembers a break. Robonaut is operated via remote control and can be directed by ground operators through cabin video and telemetry. The half-a-mechanical astronaut also can be controlled by a crewmember wearing a vest, specialized gloves, and a 3D visor. Through this technology, Robonaut mimics the wearer’s movements in Wii-like fashion. In the future, the torso will be given legs and used to perform tasks both inside and outside the ISS.

6. Night lights—Lots of them

The publicly-accessible, online Gateway to Astronaut Photography of Earth contains photographs from space beginning with the early 1960s up to recent days. A million-plus of these images were taken from the space station, approximately 30 percent of them at night. These photographs are the highest-resolution night imagery available from orbit, thanks to a motorized tripod that compensates for the station’s speed—approximately 17,500 mph—and the motion of the Earth below. Scientists are asking for help cataloging the images through a crowd-source project called Cities at Night. It includes three components: Dark Skies of ISS, which asks people to sort images into cities, stars, and other categories (something computers aren’t good at); Night Cities, which relies on people to match the images to positions on maps; and Lost at Night, which seeks to identify cities within 310-mile-diameter images. Ultimately, the data generated could help save energy, contribute to better human health and safety, and improve our understanding of atmospheric chemistry.

7. Channeling Captain Kirk

Famous explorers kept journals that give us insight into what it took to survive extreme missions, such as reaching the South Pole. Spending months confined in cramped quarters orbiting the earth is one of today’s extreme missions, and for this study, researchers asked 10 crew members aboard the station to keep journals. Crew members wrote on a laptop at least three times a week, and investigators identified 24 major categories of entries with behavioral implications. Ten of those categories accounted for 88 percent of the text: work, outside communications, adjustment, group interaction, recreation/leisure, equipment, events, organization/management, sleep, and food. Men and women from various specialties such as science and engineering and both military and civilians participated. Studying small groups living and working in isolation and confinement is like studying social issues with a microscope, scientists say.

8. The Force is strong here

This project evaluated funky footwear designed to measure exercise load. NASA developed the Advanced Resistive Exercise Device, which supplies resistance through the power of vacuum cylinders, to give crew members the ability to do weight-bearing exercise in space. Weight-bearing exercise is critical to helping reduce the loss of bone density and skeletal muscle strength that astronauts experience during spaceflight. Four crew members exercised while wearing the high-tech, spring-bottomed sandals, which, like a kind of enhanced bathroom scale, measured the loads and the torque, or twisting force, they applied. The data will help determine the best exercise regimens for safe and effective bone and muscle strength maintenance during spaceflight.

9. Squids in space.

Hawaiian bobtail squids and their symbiotic luminescent bacterium take a ride to the space station. Rather than the start of a joke, this was part of an experiment, performed in September, to look at the effect of microgravity on microbe-dependent animal development and its implications for human health. The squid were inoculated with their symbiotic bacteria once in orbit on the space station and allowed to develop for approximately 24 hours. Researchers closely examined them and found that the bacteria were able to colonize squid tissue in microgravity conditions. The experiment also illustrated the feasibility of using these animals as subjects for microgravity research, so expect to see more squid in space in the future.

10. My microbes grow better than your microbes

For this project, people collected swabs of micro-organisms from museums, historical monuments, football stadiums, and weird places like Sue the T. Rex at Chicago’s Field Museum, the set of the Today Show, and the Liberty Bell. Scientists at University of California - Davis transferred those samples to Petri dishes, incubated them to see which grew into colonies, and identified 48 to send to the space station. Scientists need to know how various microbes behave in space before we seal up people and their microbes in a spacecraft for a long trip together to Mars. The 48 samples and identical cultures on Earth will be analyzed to see how their growth differs between microgravity and the ground. Each microbe has an online trading card that tells where it was collected, how well it grows, and some interesting facts about it.

11. Sloshing around the station

In space, liquids move differently than they do on earth, but the physics of this motion are not well understood. Researchers at the Florida Institute of Technology, Massachusetts Institute of Technology and NASA’s Kennedy Space Center performed a series of experiments on slosh dynamics in the station using robotic, free-floating satellites that can independently navigate and re-orient themselves. Researchers hope to design an externally mounted fuel tank that is driven from inside the station by two of these devices to simulate a launch vehicle upper-stage propellant tank and the maneuvers of real vehicles. The experiments will improve computer models of how liquid fuel behaves to make rockets safer.

12. Ant Farm

This investigation compared the behavior of groups of ants in normal gravity and in microgravity and measured how interactions among ants depend on the number of ants in a given area. Eight ant habitats with approximately 100 residents each launched to the space station, where scientists used cameras and software to analyze their movement patterns and interaction rates. Ant colony behavior is a combination of responses by individual ants to local cues, and previous studies suggest ants use the rate at which an individual meets other ants to determine how many of them are in the area. This estimation of group density is needed in many different situations, such as searching for food. When there are many ants in a small space, each ant moves round and round in roughly the same place, but when density is low, each ant walks a straighter path to cover more ground. Data on the ant colony’s adaptations can be used to build various algorithms, or sets of steps followed in order to solve a mathematical problem. For example, ant-based algorithms could help scientists develop cheaper, more efficient strategies for robot-based searching and exploration.

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15 Subatomic Word Origins
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In July 2017, researchers at the European Organization for Nuclear Research (CERN) found evidence for a new fundamental particle of the universe: Ξcc++, a special kind of Xi baryon that may help scientists better understand how quarks are held together. Is that Greek to you? Well, it should be. The names for many of the particles that make up the universe—as well as a few that are still purely theoretical—come from ancient Greek. Here’s a look at 15 subatomic etymologies.

1. ION

An ion is any atom or molecule with an overall electric charge. English polymath William Whewell suggested the name in an 1834 letter to Michael Faraday, who made major discoveries in electromagnetism. Whewell based ion on the ancient Greek verb for “go” (ienai), as ions move towards opposite charges. Faraday and Whewell had previously considered zetode and stechion.


George Stoney, an Anglo-Irish physicist, introduced the term electron in 1891 as a word for the fundamental unit of charge carried by an ion. It was later applied to the negative, nucleus-orbiting particle discovered by J. J. Thomson in 1897. Electron nabs the -on from ion, kicking off the convention of using -on as an ending for all particles, and fuses it with electric. Electric, in turn, comes from the Greek for “amber,” in which the property was first observed. Earlier in the 19th century, electron was the name for an alloy of gold and silver.


The electron’s counterpart, the positively charged proton in the nuclei of all atoms, was named by its discoverer, Ernest Rutherford. He suggested either prouton or proton in honor of William Prout, a 19th-century chemist. Prout speculated that hydrogen was a part of all other elements and called its atom protyle, a Greek coinage joining protos ("first") and hule ("timber" or "material") [PDF]. Though the word had been previously used in biology and astronomy, the scientific community went with proton.


Joining the proton in the nucleus is the neutron, which is neither positive nor negative: It’s neutral, from the Latin neuter, “neither.” Rutherford used neutron in 1921 when he hypothesized the particle, which James Chadwick didn’t confirm until 1932. American chemist William Harkins independently used neutron in 1921 for a hydrogen atom and a proton-electron pair. Harkins’s latter application calls up the oldest instance of neutron, William Sutherland’s 1899 name for a hypothetical combination of a hydrogen nucleus and an electron.


Protons and neutrons are composed of yet tinier particles called quarks. For their distinctive name, American physicist Murray Gell-Mann was inspired in 1963 by a line from James Joyce’s Finnegan’s Wake: “Three quarks for Muster Mark.” Originally, Gell-Mann thought there were three types of quarks. We now know, though, there are six, which go by names that are just as colorful: up, down, charm, strange, top, and bottom.


Made up of a quark and an antiquark, which has identical mass but opposite charge, the meson is a short-lived particle whose mass is between that of a proton and an electron. Due to this intermediate size, the meson is named for the ancient Greek mesos, “middle.” Indian physicist Homi Bhabha suggested meson in 1939 instead of its original name, mesotron: “It is felt that the ‘tr’ in this word is redundant, since it does not belong to the Greek root ‘meso’ for middle; the ‘tr’ in neutron and electron belong, of course, to the roots ‘neutr’ and ‘electra’.”


Mesons are a kind of boson, named by English physicist Paul Dirac in 1947 for another Indian physicist, Satyendra Nath Bose, who first theorized them. Bosons demonstrate a particular type of spin, or intrinsic angular momentum, and carry fundamental forces. The photon (1926, from the ancient Greek for “light”) carries the electromagnetic force, for instance, while the gluon carries the so-called strong force. The strong force holds quarks together, acting like a glue, hence gluon.


In 2012, CERN’s Large Hadron Collider (LHC) discovered a very important kind of boson: the Higgs boson, which generates mass. The hadrons the LHC smashes together at super-high speeds refer to a class of particles, including mesons, that are held together by the strong force. Russian physicist Lev Okun alluded to this strength by naming the particles after the ancient Greek hadros, “large” or “bulky,” in 1962.


Hadrons are opposite, in both makeup and etymology, to leptons. These have extremely tiny masses and don’t interact via the strong force, hence their root in the ancient Greek leptos, “small” or “slender.” The name was first suggested by the Danish chemist Christian Møller and Dutch-American physicist Abraham Pais in the late 1940s. Electrons are classified as leptons.


Another subtype of hadron is the baryon, which also bears the stamp of Abraham Pais. Baryons, which include the more familiar protons and neutrons, are far more massive, relatively speaking, than the likes of leptons. On account of their mass, Pais put forth the name baryon in 1953, based on the ancient Greek barys, “heavy” [PDF].


Quirky Murray Gell-Mann isn't the only brain with a sense of humor. In his 2004 Nobel Prize lecture, American physicist Frank Wilczek said he named a “very light, very weakly interacting” hypothetical particle the axion back in 1978 “after a laundry detergent [brand], since they clean up a problem with an axial current” [PDF].


In ancient Greek, takhys meant “swift,” a fitting name for the tachyon, which American physicist Gerald Feinberg concocted in 1967 for a hypothetical particle that can travel faster than the speed of light. Not so fast, though, say most physicists, as the tachyon would break the fundamental laws of physics as we know them.


In 2003, the American physicist Justin Khoury and South African-American theoretical physicist Amanda Weltman hypothesized that the elusive dark energy may come in the form of a particle, which they cleverly called the chameleon. Just as chameleons can change color to suit their surroundings, so the physical characteristics of the chameleon particle change “depending on its environment,” explains Symmetry, the online magazine dedicated to particle physics. Chameleon itself derives from the ancient Greek khamaileon, literally “on-the-ground lion.”

For more particle names, see Symmetry’s “A Brief Etymology of Particle Physics,” which helped provide some of the information in this list.

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Look Up! The Orionid Meteor Shower Peaks This Weekend
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Ethan Miller/Getty Images

October is always a great month for skywatching. If you missed the Draconids, the first meteor shower of the month, don't despair: the Orionids peak this weekend. It should be an especially stunning show this year, as the Moon will offer virtually no interference. If you've ever wanted to get into skywatching, this is your chance.

The Orionids is the second of two meteor showers caused by the debris field left by the comet Halley. (The other is the Eta Aquarids, which appear in May.) The showers are named for the constellation Orion, from which they seem to originate.

All the stars are lining up (so to speak) for this show. First, it's on the weekend, which means you can stay up late without feeling the burn at work the next day. Tonight, October 20, you'll be able to spot many meteors, and the shower peaks just after midnight tomorrow, October 21, leading into Sunday morning. Make a late-night picnic of the occasion, because it takes about an hour for your eyes to adjust to the darkness. Bring a blanket and a bottle of wine, lay out and take in the open skies, and let nature do the rest.

Second, the Moon, which was new only yesterday, is but a sliver in the evening sky, lacking the wattage to wash out the sky or conceal the faintest of meteors. If your skies are clear and light pollution low, this year you should be able to catch about 20 meteors an hour, which isn't a bad way to spend a date night.

If clouds interfere with your Orionids experience, don't fret. There will be two more meteor showers in November and the greatest of them all in December: the Geminids.


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