The International Space Station is the longest-running continuously inhabited human outpost in space – this year it celebrated its 15th anniversary. As the ISS orbits the Earth it is essentially in a state of free fall, counteracting the Earth’s gravity and providing an ideal platform for science in space.
Science aboard the ISS is decidedly cross-disciplinary, including fields as diverse as microbiology, space science, fundamental physics, human biology, astronomy, meteorology and Earth observation to name a few. But let’s take a look at some of the biggest findings.
1. The fragility of the human body
The effects of the space environment on the human body during long duration spaceflight are of significant interest if we want to one day venture far beyond the Earth. A crewed journey to Mars, for example, may take a year, and the same time again for the return leg.
Microgravity research on the ISS has demonstrated that the human body would lose considerable bone and muscle mass on such a mission. Mitigation technology, involving the use of resistive exercise devices, has shown that it is possible to substantially alleviate bone and muscle loss. Coupled with other studies into appropriate nutrition and drug use, these investigations may lead to improvements in the treatment of osteoporosis, a condition affecting millions of people across the globe.
2. Interplanetary contamination
A long-term goal of many space agencies is to fly humans to Mars. The red planet is of particular interest because it is one of the most accessible locations in which past or present extraterrestrial life may exist. It is imperative, therefore, that we do not inadvertently contaminate Mars with terrestrial organisms. Likewise, we must be careful not to back-contaminate Earth with any possible Martian life forms during a sample return mission.
Certain hardy bacterial spores, such as the Bacillus subtilis in the picture were exposed to space aboard the ISS, but shielded from solar UV-radiation, and demonstrated a high survival rate. The space vacuum and temperature extremes alone were not enough to kill them off. These remarkable bugs could be capable of surviving an interplanetary space flight to Mars and live there, under a thin layer of soil, were they to be accidentally deposited by a spacecraft.
This finding has huge implications; if microorganisms, or their DNA, can survive interplanetary spaceflight, albeit by natural means, it leaves open the possibility that life on Earth may originally have arrived from Mars, or elsewhere .
3. Growing crystals for medicine
A key challenge in developing effective medicines is understanding the shape of protein molecules in the human body. Proteins are responsible for a huge range of biological functions, including DNA replication and digestion – and protein crystallography is an essential tool for understanding protein structure. Crystal growth within a fluid on Earth is somewhat inhibited by gravity-driven convection and the settling out of denser particles at the bottom of the fluid vessel.
Crystals in a microgravity environment may be grown to much larger sizes than on Earth, enabling easier analysis of their micro-structure. Protein crystals grown on the ISS are being used in the development of new drugs for diseases such as muscular dystrophy and cancer.
4. Cosmic rays and dark matter
Space is permeated by a constant flux of energetic charged particles called cosmic rays. When cosmic rays encounter the Earth’s atmosphere they disintegrate, producing a shower of secondary particles which can be detected at ground level. Some cosmic rays may emanate from explosive events such as supernovae or, closer to home, flares on our own sun. But in many cases their source is unknown.
In order to better understand these enigmatic particles, we need to catch them before they reach the atmosphere. Mounted on the ISS is the Alpha Magnetic Spectrometer (AMS), the most sensitive particle detector ever launched into space. This device collects cosmic rays and measures both their energy and incoming direction.
Science news in pictures
Science news in pictures
1/18 Vegetables grow well in soil from Mars
Scientists have taken a leaf out of the script of The Martian by showing how easy it would be to grow your own veg on the Red Planet. In the hit Ridley Scott film, a stranded astronaut played by Matt Damon uses his botanical skills to cultivate potatoes. Now his success has been emulated by researchers in the Netherlands who harvested tomatoes, peas, rye, rocket, radish and cress raised on simulated Martian soil supplied by Nasa
2/18 Ancient Roman 'leisure complex' unearthed in Jerusalem
An ancient Roman estate complete with its own wine press and bathhouse has been unearthed in Jerusalem. A series of buildings dating back at least 1,600 years were discovered underneath the city's famous Schneller Orphanage which operated on the site from 1860 until the end of the Second World War, when it was turned into an army base. The ruins were discovered by archaeologists from the Israel Antiquities Authority who were excavating the site ahead of building new flats for the city's Orthodox Jewish community
3/18 Scientists discover possible new species of deep-sea octopus nicknamed 'Casper'
Scientists believe they may have found a new species of octopus likened in appearance to Casper, the friendly cartoon ghost. Researchers with the US National Oceanic and Atmospheric Administration made the discovery by chance as they searched the seabed on an unrelated mission collecting geological samples. Teams were operating an unmanned submarine on the Pacific Ocean floor at depths of more than four kilometres (two-and-a-half miles) in the Hawaiian Islands when they spotted the unusual creature
4/18 Black hole captured eating a star then vomiting it back out
Astronomers have captured a black hole eating a star and then sicking a bit of it back up for the first time ever. The scientists tracked a star about as big as our sun as it was pulled from its normal path and into that of a supermassive black hole before being eaten up. They then saw a high-speed flare get thrust out, escaping from the rim of the black hole. Scientists have seen black holes killing and swallowing stars. And the jets have been seen before.But a new study shows the first time that they have captured the hot flare that comes out just afterwards. And the flare and then swallowed star have not been linked together before
5/18 'Male and female brains' aren't real
Brains cannot be categorised into female and male, according to the first study to look at sex differences in the whole brain. Specific parts of the brain do show sex differences, but individual brains rarely have all “male” traits or all “female” traits. Some characteristics are more common in women, while some are more common in men, and some are common in both men and women, according to the study
6/18 Dog-sized horned dinosaur fossil found shows east-west evolutionary divide in North America
A British scientist has uncovered the fossil of a dog-sized horned dinosaur that roamed eastern North America up to 100 million years ago. The fragment of jaw bone provides evidence of an east-west divide in the evolution of dinosaurs on the North American continent. During the Late Cretaceous period, 66 to 100 million years ago, the land mass was split into two continents by a shallow sea. This sea, the Western Interior Seaway, ran from the Gulf of Mexico to the Arctic Ocean. Dinosaurs living in the western continent, called Laramidia, were similar to those found in Asia
7/18 Asteroid to skim past Earth on Halloween 2015
A huge asteroid is set to skim by Earth on Halloween, just three weeks after it was first spotted. The rock is travelling through space at 78,000 miles per hour, and will fly past the Earth at a distance of only 300,000 miles – only slightly further away than our moon, and easily close enough for Nasa to class it a potentially hazardous object. The asteroid is bigger than a skyscraper
8/18 Life on Earth appeared hundreds of millions of years earlier than previously thought
Life may have come to earth 4.1 billion years ago, hundreds of millions of years earlier than we knew. The discovery, made using graphite that was trapped in ancient crystals, could mean that life began "almost instantaneously" after the Earth was formed. The researchers behind it have described the discovery as “a potentially transformational scientific advance”. Previously, life on Earth was understood to have begun when the inner solar system was hit by a massive bombardment from space, which also formed the moon's craters
9/18 Earth could be at risk of meteor impacts
Earth could be in danger as our galaxy throws out comets that could hurtle towards us and wipe us out, scientists have warned. Scientists have previously presumed that we are in a relatively safe period for meteor impacts, which are linked with the journey of our sun and its planets, including Earth, through the Milky Way. But some orbits might be more upset than we know, and there is evidence of recent activity, which could mean that we are passing through another meteor shower. Showers of meteors periodically pass through the area where the Earth is, as gravitational disturbances upset the Oort Cloud, which is a shell of icy objects on the edge of the solar system. They happen on a 26-million year cycle, scientists have said, which coincide with mass extinctions over the last 260-million years
10/18 Genetically-engineered, extra-muscular dogs
Chinese scientists have created genetically-engineered, extra-muscular dogs, after editing the genes of the animals for the first time. The scientists create beagles that have double the amount of muscle mass by deleting a certain gene, reports the MIT Technology Review. The mutant dogs have “more muscles and are expected to have stronger running ability, which is good for hunting, police (military) applications”, Liangxue Lai, one of the researchers on the project. Now the team hope to go on to create other modified dogs, including those that are engineered to have human diseases like muscular dystrophy or Parkinson’s. Since dogs’ anatomy is similar to those of humans’, intentionally creating dogs with certain human genetic traits could allow scientists to further understand how they occur
11/18 Nasa confirms Mars water discovery
Nasa has announced that it has found evidence of flowing water on Mars. Scientists have long speculated that Recurring Slope Lineae — or dark patches — on Mars were made up of briny water but the new findings prove that those patches are caused by liquid water, which it has established by finding hydrated salts.
12/18 Bees in the Rocky Mountains are evolving shorter tongues
With warmer summers, flowers in the Rockies have become shallower and more suited to shorter-tongued bees
13/18 The majority of the UK public believe in aliens
The titular alien character from 2011's 'Paul' - a poll has found the majority of the public in Britain, Germany and the US believe that intelligent life is out there in the universe
14/18 Researchers discover 'lost world' of arctic dinosaurs
Scientists say that the new dinosaur, known as Ugrunaaluk kuukpikensis, “challenges everything we thought about a dinosaur’s physiology”. Florida State University professor of biological science Greg Erickson said: “It creates this natural question. How did they survive up here?”
15/18 Scientists find exactly what human corpses smell like
New research has become the first to isolate the particular scent of human death, describing the various chemicals that are emitted by corpses in an attempt to help find them in the future. The researchers hope that the findings are the first step towards working on a synthetic smell that could train cadaver dogs to be able to more accurately find human bodies, or to eventually developing electronic devices that can look for the scent themselves.
16/18 The Syrian civil war has caused the first ever withdrawal from the 'doomsday bank'
Researchers in the Middle East have asked for seeds including those of wheat, barley and grasses, all of which are chosen because especially resistant to dry conditions. It is the first withdrawal from the bank, which was built in 2008. Those researchers would normally request the seeds from a bank in Aleppo. But that centre has been damaged by the war — while some of its functions continue, and its cold storage still works, it has been unable to provide the seeds that are needed by the rest of the Middle East, as it once did.
17/18 A team of filmmakers in the US have made the first ever scale model of the Solar System in a Nevada desert
Illustrations of the Earth and moon show the two to be quite close together, Mr Overstreet said. This is inaccurate, the reason being that these images are not to scale.
18/18 Academics claim a full bladder makes for a better liar
People lie more convincingly if they have a full bladder, according to research by academics at California State University. Iris Blandón-Gitlin's team asked 22 students to lie to a panel of interviewers. Half were given 700ml to drink before the interview and the other half, just 50ml. The students with the full bladders showed fewer signs that they were lying and their untrue answers were longer and more detailed, meaning interviewers were less able to detect that they were telling porkies. PM David Cameron has previously attested to giving speeches on a full bladder.
In 2013, early results showed that cosmic ray electrons and their anti-matter counterparts, positrons, emanated from all directions in space, rather than from specific locations.
Approximately one quarter of the mass-energy of the universe is believed to be comprised of dark matter, a substance of unknown composition, which may be a source of cosmic rays. The theorised presence of dark matter envisages a halo of the material surrounding the Milky Way (and other galaxies), and is thus supported by the isotropic nature of the cosmic ray electrons and positrons detected by AMS, essentially coming at us from all directions in space.
It has never been detected directly and it’s true nature is one of the greatest unanswered questions in modern astrophysics.
5. Efficient combustion
Deliberately starting a fire on an orbital space station does not sound, initially, like a good idea. It turns out, however, that the physics of flames in microgravity is quite interesting. The flame extinguishment study is an understandably carefully designed facility whereby tiny droplets of fuel, which form into spheres under microgravity, are ignited.
Flames on Earth assume their familiar shape because gravity-driven convection results in an updraught of air, drawing the burning mixture of fuel and gas upwards. In microgravity there is no updraught and so a flame assumes a diffuse spherical shape around the combustion source. Further, the yellow colour of a flame is produced by the incandescence of tiny soot particles. Soot forms from incomplete burning of the fuel and is a pollutant.
In microgravity, the combustion of a fuel is more complete and hence more efficient. A candle flame that would appear yellow on Earth, actually burns with a blue colour in microgravity and produces much less smoke. This kind of research enables the study of soot formation processes which has negative impacts on the environment and human health, and how droplets of fuel in a combustion engine transition from a liquid to a gas as they burn. This may one day lead to more efficient designs for combustion engines on Earth.
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