Are Zebras Black with White Stripes or White with Black Stripes?

Updated On: 11 Nov 2021 By Ishan Daftardar

Table of Contents

• Zebra’s Stripes are Formed Due To Selective Pigmentation
• The Genes That Control Creating White Stripes on Zebras
• What is the Purpose of a Zebra’s Stripes?

There has long been a popular belief that zebras were white animals with black stripes, but scientifically, it turns out to be the opposite. According to the principles of embryology, the real/original color of zebras is BLACK. The white color is actually the stripe around the main black background of their body.

There is no denying that zebras are one of the most exotic and breathtaking horse species, but there are also plenty of questions about these beautiful animals.

1) Are zebras white with black stripes or black with white stripes?

2) What is the purpose of having such a peculiar pattern on their bodies?

Look no further because researchers have finally landed on some answers!

In the Medieval era, people believed that zebras had white bodies with black stripes. The proof of this hypothesis lay in the fact that they had white underbellies. This makes logical sense; white is a lighter color; it would be the base to a darker black.

White Underbelly (Credits: Wojciech PLONKA/Shutterstock)

However, recent studies prove the opposite: zebras are actually black with white stripes!

Zebra’s Stripes are Formed Due To Selective Pigmentation

The stripes are mainly caused by selective pigmentation.

Zebra embryos start completely black. Cells called melanocytes produce the black pigment melanin, which colors the hair and skin of a zebra. After being produced, the melanin will make its way to the skin cells and the hair shaft.

This pigmentation is controlled by the activation or inhibition of certain genes involved in the production and transport of melanin.

In the last stage of embryo development in the zebra, melanocytes in certain areas have their melanin-producing genes turned off, resulting in the white stripes we see in a zebra.

This pattern of pigmentation is called selective pigmentation.

However, the zebra’s skin does not turn white in these regions due to the separate paths that lead to skin color and hair color. Thus, the skin of the zebra remains black, while the fur may be white or black.

Differences in their stripe pattern can recognize different zebra species.

Depending on when these genes are switched on, the stripe patterns form accordingly. Studies have shown that the earlier the melanocyte matures, the thicker the stripes of the zebra. This is an example of heterochrony. Simply put, it is the difference in the timing and duration of certain genes being turned on or off between different organisms.

The Genes That Control Creating White Stripes on Zebras

While we know this much, the molecular pathways and which genes are involved remain a mystery. In 2016, a study published in the journal Nature suggested that the Alx3 gene is involved in forming stripes. Since zebras are difficult to keep in the laboratory, the researchers instead examined the stripe pattern of the African striped mouse.

Alx3 is a transcription factor. A transcription factor is a molecule, usually a protein, that can turn certain genes on or off. It is like a switch master. The cell maintains strict control over how and when the transcription factor can turn its target gene on or off. When the transcription factor finishes its job, the cell calls it off duty until needed again.

Alx3 was found before pigmented stripes. It also suppresses a gene called Mitf, which controls how melanocytes mature, leading to light stripes.

Although these were found in rodents, evolutionarily speaking, it could help scientists determine the purpose of stripes, whether they are on zebras or other creatures!

What is the Purpose of a Zebra’s Stripes?

This question doesn’t have a single, straightforward answer; there are several hypotheses:

1) Camouflage

The stripes of a zebra actually serve as camouflage to deter its main predators: lions and hyenas. As the animals herd together, experts believe that the mass of stripes can confuse predators by acting as an optical illusion and effectively merging their figures. Therefore, a herd of zebras can create the optical illusion of a huge mass, thus deterring any predators from taking on the herd alone.

2) Regulate body temperature

Zebras spend a lot of time grazing on open plains, which means that they have to endure the intense African heat for long periods of time. Zebras with the most prominent torso stripes generally live in the northern equatorial region of their range. In contrast, those with less prominent torso stripes are more common in their range’s southern, cooler regions. This geographical distribution supports the stripes’ proposed utility as a heat-regulating tool.

Both of the above ideas have been popular theories in the past, but they do not have much evidence to support them.

3) Flies and other pests

Tsetse flies are a major problem for animals in tropical Africa. These parasitic flies cause the disease trypanosomiasis in both animals and humans. One hypothesis supported by some evidence is that zebra stripes confuse the flies. A study published in 2014 in Nature found that flies thought to be a common pest for Zebras are less likely to sit on black and white striped surfaces.

In 2019, Japanese researchers painted cows black and white and found that fly bites were reduced by 50%. They have proposed this method as a possible prevention technique for spreading disease by these tsetse flies.

And there you have it… a zebra is a black horse with white stripes because they do not want flies to suck their blood!

References

1. University of California, Santa Barbara Science Line
2. Zebra Stripes Not for Camouflage - UC Davis
3. UC Davis
4. Nature Communications

The world's biggest laser: Function, fusion power and solving a supernova


By Andrew May 

The world's biggest laser is inside America’s National Ignition Facility that can recreate the conditions that exist inside stars.

A laser-induced fusion reaction taking place inside National Ignition Facility's target chamber. (Image credit: Lawrence Livermore National Laboratory (LLNL) )

If someone told you that the world's biggest laser was in California that has something to do with space and national defence, you might imagine it was a super-weapon designed to blast enemy satellites out of the sky. But the reality is quite different. The new laser is a unique research tool for scientists, capable of creating the extreme conditions that exist inside stars and nuclear explosions.

WHERE IS THE WORLD'S LARGEST LASER?

The giant laser is located at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California, and it goes by the rather cryptic name of the National Ignition Facility (NIF). That’s because, in the context of nuclear science, “ignition” has a very specific meaning according to the Lawrence Livermore National Laboratory. It refers to the point at which a fusion reaction becomes self-sustaining – a condition that is found inside the sun and other stars, but is extremely difficult to achieve in an earthbound laboratory. Triggering nuclear fusion requires enormously high temperatures and pressures, and that’s where NIF’s giant laser comes in.

Related: What is antimatter, how is it made and is it dangerous?

Operational since March 2009, NIF fills a 10-story building as big as three football fields. It has 192 separate laser beams, which direct all their energy onto a small target less than a centimeter in size. This happens in a single, carefully coordinated pulse lasting just a few billionths of a second. The resulting flash of light creates the extreme conditions needed for fusion to occur, including temperatures of 180 million degrees Fahrenheit (100 million Celsius) and pressures 100 billion times that of the Earth’s atmosphere.

LASER BEAM

To understand how NIF achieves such an astounding feat, it’s worth taking a closer look at just what a laser beam is. The word laser stands for “light amplification by stimulated emission of radiation,” and that holds the key to how they work. Perhaps the most familiar example of amplification is in a sound system, where additional energy is pumped into an audio signal to make it louder, while preserving its exact characteristics so we hear the result without any distortion. In effect that’s what a laser does — but with light instead of sound.

In the case of NIF, the 192 laser beams are progressively amplified as they pass back and forth through slabs of neodymium-doped phosphate glass. The energy for this amplification comes from a series of powerful flash lamps surrounding the glass slabs. Before the beams go through, the intense white light from these lamps is used to raise the neodymium atoms to higher-than-normal energy levels.

Then, as a laser pulse passes through the glass, it triggers the "stimulated emission" referred to in the laser acronym. The excess energy in the neodymium atoms is released in the form of more light waves, traveling in exactly the same direction and with exactly the same wavelength as the original pulse. Thus the laser beams are progressively amplified at each pass, eventually emerging more than a quadrillion times as powerful as when they entered.

FUSION POWER

Nuclear fusion is a reaction in which the nuclei of light atoms, such as hydrogen, combine to make heavier ones such as helium. It’s essential to life on Earth because it powers the Sun, according to NASA, which is our primary source of light and heat. For decades scientists have endeavored to replicate this process with a controlled, self-sustaining fusion reaction on Earth.

In many ways this would be the perfect energy source, free of the radioactive waste associated with traditional nuclear power stations, or the carbon emissions of fossil fuels according to the UK Atomic Energy Authority. Unfortunately this has proved an elusive goal, and the only fusion reactions that have found a practical use to date are the violently destructive ones that power thermonuclear weapons.

It was in this context that NIF was originally set up. The primary purpose of LLNL is to ensure the safety, security and reliability of America’s nuclear deterrent. At one time this involved the active development and testing of new weapons, but thankfully this is no longer the case. LLNL now seeks to maintain the integrity of existing weapons without full-scale testing, and NIF plays a crucial role in this. It’s uniquely capable of creating the enormous temperatures and pressures that scientists need in order to study the conditions inside a detonating nuclear weapon.

Related: What was the Manhattan Project?

While weapon-related research still accounts for the bulk of NIF’s activities, around 8 per cent of its time each year is set aside for more peaceful experiments. These include studies of nuclear fusion in the sun and other stars, as well as exploring technologies that could facilitate the use of fusion as a future power source on Earth. But not all NIF’s experiments are related to fusion. Because the laser creates such extreme conditions in terms of temperature and pressure, it can be used to study other situations where these conditions occur, such as the expanding shock waves around supernova explosions, or the incredibly dense cores of giant planets.

NIF can do research that previously required nuclear explosions, such as the Bravo nuclear test in 1954. (Image credit: United States Department of Energy)

HOW DO LASERS WORK?


According to NIF, its ultimate purpose is to focus all the energy from an array of powerful laser beams onto a pea-sized target. The lasers don’t fire continuously, but in a brief pulse just 20 billionths of a second long. That’s enough to raise the target to the enormous temperatures and pressures the researchers need.

From the initial creation of the laser pulse to blasting the target only takes a few microseconds, but a lot happens in that time. To start with, a single weak pulse is created in the master oscillator room. This is then split into a total of 192 separate beams inside the two giant laser bays, where the beams are progressively amplified as they pass back and forth through the system. The energy for this comes from super-powerful flashlamps which illuminate a series of glass slabs through which the beams pass, constantly gaining energy as they do so.

During the amplification process the beams all travel in parallel, but once they are sufficiently powerful they are rearranged into two conical shapes inside the target chamber. These converge onto the target from above and below, all arriving at the same instant to deliver their energy in a single massive flash.

The huge spherical target chamber seen prior to installation in June 1999. (Image credit: Lawrence Livermore National Laboratory (LLNL))

“I was so overwhelmed by the sheer size of the NIF laser that I nearly fainted on my first visit,” said Jena Meineck, a plasma physicist who is researching the origin of magnetic fields in the universe at the National Ignition Facility.”Standing next to it is like standing next to Niagara Falls – you feel paralyzed by the tremendous power of this machine that towers above you. Running an experiment at NIF is not like running an experiment at any other laser facility. The conditions obtained are so extreme that, to some extent, you have no idea what to expect. All you know is that something special is about to happen.”

SPACE LASERS

While the conditions created inside NIF’s target chamber are far beyond anything normally seen on Earth, they’re much more typical of certain astrophysical environments. This makes NIF an invaluable tool for space research. The interior of a star, for example, undergoes fusion in much the same way – but on a far larger scale – as the nuclear explosions NIF was designed to emulate. In 2017, as part of LLNL’s “Discovery Science” program, it was used to create conditions resembling a stellar interior, allowing researchers to collect data that would be impossible to obtain by any other means.

NIF has also been used to study the physics of supernova shock waves and the ubiquity of cosmic magnetic fields. Thanks to a series of NIF experiments, the latter can now be explained in terms of a phenomenon called the “turbulent dynamo” effect, according to Dr. Meinecke. “Fast-moving shock waves may be the birthplace of the ubiquitous magnetic fields that pervade our universe,” Dr Meinecke told us, “The strength of these fields increases until a unique phenomenon occurs called turbulent dynamo. This is a regime of nonlinear magnetic field amplification commonly observed in the universe, but only recently created here on Earth by our team.”

In the everyday world, a dynamo is a device for converting mechanical energy into electromagnetic form, and the NIF experiments suggest that an analogous process in the early universe was responsible for boosting initially weak magnetic fields into the powerful ones that now permeate galaxies.

SOLVING A SUPERNOVA

Supernovae are enormously powerful explosions, occurring when large stars run out of nuclear fuel. They create extreme conditions that aren’t seen anywhere else in the universe, which makes them intriguing to astronomers. Even so, they’re not fully understood because nearby supernovas are so rare. For example, scientists were mystified as to how supernova shock waves are able to accelerate cosmic rays almost to the speed of light. Thanks to NIF, however, the puzzle has been solved. According to LLNL, in 2020 researchers used the giant laser to recreate supernova-like conditions on a miniature scale, and found that turbulence in the shock waves is responsible for the anomalous acceleration. That’s something that could never have been discovered purely from astronomical observations.

Another use the giant laser can be put to is compressing material to extremely high densities – much higher than anything found here on Earth, but comparable to the conditions at the centre of giant planets such as Jupiter and Saturn. It’s been used, for example, to study the way in which hydrogen turns into a metal under such conditions. And in 2014, NIF was used to squeeze a diamond crystal to a pressure equivalent to that at the centre of Saturn – 14 times the pressure in the Earth’s own core. A particular challenge in this experiment was to avoid creating enormously high temperatures. While these are desirable in fusion experiments, they’re unrealistic in the context of a planetary core. With careful design, however, the experiment succeeded in compressing the diamond to a density similar to that of lead – and provided a wealth of data for planetary scientists in the process.

It’s conceivable, too, that NIF may have practical space applications of a completely different kind. This is because fusion power, in addition to its potential applications here on Earth, might also be a viable option for spacecraft propulsion. Over the years a number of possible designs have been put forward, but most of these produce fusion reactions in a completely different way from NIF. In 2005, however, LLNL scientist Charles Orth worked with NASA to develop a space propulsion concept based on the selfsame principles as NIF. Called VISTA, for “Vehicle for Interplanetary Transport Applications”, the design employs a conical arrangement of laser beams to initiate fusion in a series of small fuel pellets, with the resulting thrust then being deflected in the desired direction with the aid of powerful magnets according to page 7 of a report by the US Department of Energy.

ADDITIONAL RESOURCES
Introduction to Laser Technology, 4th Edition
Future Of Fusion Energy, The (Popular Science)
Supernova Explosions (Astronomy and Astrophysics Library)

Andrew May holds a PhD in astrophysics from Manchester University, U.K. For 30 years, he worked in the academic, government and private sectors, before becoming a science writer where he has written for Fortrean Times, How It Works, All About Space, Popular Science, among others. He has also written a selection of books including Cosmic Impact and Astrobiology: The Search for Life Elsewhere in the Universe, published by Icon Books.

RED SCIENCE

Nuclear fusion: why the race to harness the power of the sun just sped up

Page added on November 25, 2021

A nervous excitement hangs in the air. Half a dozen scientists sit behind computer screens, flicking between panels as they make last-minute checks. “Go and make the gun dangerous,” one of them tells a technician, who slips into an adjacent chamber. A low beep sounds. “Ready,” says the person running the test. The control room falls silent. Then, boom.

Next door, 3kg of gunpowder has compressed 1,500 litres of hydrogen to 10,000 times atmospheric pressure, launching a projectile down the 9-metre barrel of a two-stage light gas gun at a speed of 6.5km per second, about 10 times faster than a bullet from a rifle.

On the monitors the scientists are checking the next stage, when the projectile slams into the target — a small transparent block carefully designed to amplify the force of the collision. The projectile needs to hit its mark perfectly flush. The slightest rotation risks derailing the carefully calibrated physics.

“Thank God,” exclaims one of the technicians, after reviewing a video playback of the impact of the scientific artillery. It was the perfect shot.

Those in the room at First Light Fusion, in a business park outside the English city of Oxford, had just witnessed another hopeful step in a 60-year mission to answer one of science’s most complex problems: how to harness the fusion reaction that powers the sun to generate clean, limitless electricity on Earth.



The potential of fusion energy, first pioneered by the Soviet Union, has tantalised scientists for decades but has always seemed just out of reach.

“Fusion is probably the greatest technical challenge humanity has ever taken on,” says Arthur Turrell, whose book The Star Builders charts the decades-long effort by engineers, physicists and mathematicians to achieve what some still believe is impossible. “How close it is depends not on time, but on the will, the investment and the commitment of resources to actually get there.”

A growing number of private companies, including First Light, are now hoping to commercialise those years of public research by proving fusion power can work and connecting it to the grid as soon as the 2030s.

Unlike nuclear fission when atoms are split, fusion does not produce significant radioactive waste and could never result in a nuclear accident, such as Chernobyl. The most efficient chemical inputs for fusion — deuterium and tritium — are also widely available.

Just one glass of the fuel created by the process has the energy potential of 1m gallons of oil and could generate, depending on the fusion approach, as much as 9m kilowatt hours of electricity, enough to power a home for more than 800 years, scientists estimate.

Those characteristics, its proponents say, mean fusion, by providing cheap, unlimited zero emissions electricity, could genuinely save the world.

“I couldn’t be more optimistic,” says Silicon Valley venture capitalist Sam Altman, who recently invested $375m in the US fusion start-up Helion. “In addition to being our best path out of the climate crisis, less expensive energy is transformational for society.”



A Soviet-era idea, taken private

Soviet physicists developed the first fusion machine in the 1950s using an approach known as magnetic confinement fusion. The tokamak — short in Russian for toroidal chamber with magnetic coils — enabled a plasma of deuterium and tritium, both hydrogen isotopes, to be held in place by powerful magnets and heated to temperatures hotter than the sun so that the atomic nuclei fuse, creating helium and releasing energy in the process.

The problem is that while scientists have become adept at fusing the two isotopes, the Soviet tokamak, and all other fusion systems developed since, require a vast amount of power. And in more than half a century of trying, no group has been able to generate more energy from a fusion reaction than the system consumes.

“When will we get electricity from fusion? Who the hell knows?” says Steven Krivit, a science writer who for 20 years has been a critical observer of fusion energy’s false starts. “Until we see somebody delivering electricity cost effectively we’re still doing science, we’re not doing technology.”

But after a series of public and private sector breakthroughs in the past six months, some industry participants are far more hopeful. In China in May a machine known as East — the Experimental Advanced Superconducting Tokamak — managed to sustain a fusion reaction at 120m degrees Celsius for a record 101 seconds. Temperatures over 100m C generally required for magnetic confinement fusion had been attained before but never sustained for such a long time.

Then in September a Boston-based start-up demonstrated the use of a high-temperature superconductor to generate a much stronger magnetic field than a traditional tokamak. The group, Commonwealth Fusion Systems, which grew out of the Massachusetts Institute of Technology, believes the discovery will enable it to make a more efficient fusion machine that will be smaller, cheaper and more viable as a commercial source of power.



Bob Mumgaard, CFS chief executive, compares the breakthrough with the evolution of computing. “Computers, back when they had vacuum tubes, took up whole rooms. Then when they had transistors you could make the computers smaller and, all of a sudden, people that weren’t doing computers could do computers,” he says.

“Fusion has so many really desirable attributes, if you think about what is required for the entire world to live in the way people deserve to live and to also have a liveable planet,” he says. The next step towards power production is the construction of a demonstration plant called Sparc, about half the size of a tennis court, which CFS hopes will achieve net energy by 2025 and then a commercial power station in the 2030s.


“We’re using known science, with new engineering and new materials,” says Francesca Ferrazza, a physicist at the Italian oil major Eni, which has collaborated with MIT since 2008 and is the largest outside investor in CFS. “The ambition would be to be a player in the [fusion energy] field with a substantial presence in various parts of the value chain,” she says.

“Fusion is coming, faster than you expect,” says Andrew Holland, chief executive of the newly formed Fusion Industry Association, which counts the number of private businesses in the sector worldwide at 35 and growing.




A patient wait

Private participation in the sector is relatively new. In the second half of the 20th century fusion research was advanced by international public consortiums and the biggest projects in the world remain government-funded.

The US Department of Energy helped establish MIT’s Plasma Fusion Center — now the Plasma Science and Fusion Center — in 1976 in response to the oil crisis and rising prices. The Joint European Torus, which remains the world’s most advanced tokamak, was opened in Culham, a village south of Oxford, in 1984. Then in 1985 US president Ronald Reagan and Mikhail Gorbachev, his Soviet counterpart, agreed to co-operate on ITER — the International Thermonuclear Experimental Reactor — the world’s largest nuclear fusion project, to ease cold war tensions.


Some experts believe ITER is still most likely to produce net energy first, but the project, a collaboration between 35 countries that remains under construction in France almost 40 years later at an estimated cost of more than $20bn, has become a byword for glacial progress.

“None of the private fusion companies would be here today without the science that was developed in the ITER programme,” says Christofer Mowry, chief executive of Canada’s General Fusion. “But the cost and timeline for ITER should not be used as a point of reference for what it takes to develop and commercialise fusion energy.”



Mowry, who joined the Jeff Bezos-backed company in 2017, is certain it will be the private sector that makes fusion power a reality. He compares it to the role Elon Musk’s SpaceX has played in advancing the prospects of commercial access to space.

“SpaceX did not invent the science of rocketry. It took 50 years of research, sprinkled a little bit of these modern technologies and made a better, faster, cheaper Apollo,” he says, referring to the US space agency programme.

General Fusion’s approach, which it calls magnetised target fusion, is unusual in that it has been designed with a commercially viable power plant in mind, Mowry says. It uses an array of steam-powered pistons to rapidly compress the plasma to fusion conditions and a wall of liquid metal to absorb the heat from the reaction, which is then used to produce steam to drive a turbine generator. Construction on its first demonstration plant is scheduled to start next year, also at Culham, and be completed in 2025.



In total, private fusion companies have raised $2.3bn in investment, according to the industry association. More than a fifth of that funding was raised just this month by Altman’s Helion, which uses yet another approach that it calls pulsed non-ignition fusion. It involves raising the temperature of the fuel to 100m C in a 40-foot-wide, six-foot-high dumbbell-shaped “plasma accelerator” to capture the energy as the reaction expands and pushes back on the system’s magnetic field. Mowry argues that the variety of approaches is one of the emerging sector’s strengths. “Private industry accepts more risk to go faster and cheaper,” he says. “That means that not all shots will go in but the world doesn’t need them all to go in.”

A tainted sector

At First Light in Oxford, the scientists’ hopes are pinned not on the gas gun — which is used to test the science but will not be part of the future power system — but on the target used to house the deuterium-tritium fuel and amplify the impact of the projectile.

First Light’s hypothesis, based on the theory of inertial confinement fusion, is that by firing a projectile at the target at speeds in excess of 20km a second — enough to travel from London to New York in 4 minutes — they can create enough energy to force the deuterium and tritium to fuse, vaporising the target, while generating the energy equivalent of burning 10 barrels of oil.


Founded by 36-year-old chief executive Nicholas Hawker and his former physics professor Yiannis Ventikos, First Light is cagey about the target’s composition and design, which the company keeps closely guarded. The replica at their headquarters — a clear cube, a little over a centimetre wide, enclosing two spherical capsules — looks like a prop from a superhero movie.



“It is the ultimate espresso capsule,” says Hawker, explaining that First Light hopes to manufacture and sell the targets to future power plants — built to its design — which would need to vaporise one every 30 seconds to generate continual power. He was drawn, he says, to “working beyond the edge of human knowledge”.

It is exactly this complexity, however, that makes claims difficult to verify and has tainted the sector.


In 1951, at the height of the cold war, Juan Perón, Argentina’s president, convinced the world his scientists had harnessed fusion power, generating global newspaper headlines. Fusion fuel would soon be available, like milk, he said, in half-litre bottles. Almost four decades later in 1989, two chemists at the University of Utah said they had been able to fuse nuclei at room temperature in a simple electrochemical cell on a lab bench, a claim that unravelled in weeks.

Such incidents continue to weigh on the industry. Krivit, the science writer, argues that until a group shows it can generate electricity from a fusion reaction, prospective investors should treat private companies’ claims with scepticism.



A First Light engineer works on an electro magnetic launcher near Oxford. One glass of the fuel created by the fusion process has the energy potential of 1m gallons of oil
A First Light engineer works on an electro magnetic launcher near Oxford © Tom Pilston/FT

Yet progress is undoubtedly being made, including at the US government’s National Ignition Facility, where in August scientists used 192 lasers to generate a fusion reaction that appears to have come the closest yet to achieving net energy.

“It was the biggest breakthrough in fusion for literally decades,” says Turrell, adding that getting fusion energy on to the grid in 2030 is a “great ambition”.

“But if they get there in 2040 instead that is still going to be a huge win for the world,” he adds. “And even if they get there after 2050 and the world has [already] reached net zero that will still be a massive win for humanity because we need a portfolio of energy sources.”

At that stage, Turrell says, fusion could be used to power energy-intensive carbon capture systems enabling the world to begin to reverse, rather than slow, some of the environmental damage brought by climate change.

Hawker echoes that view. Existing renewable energy sources, particularly wind and solar power, can be scaled up to replace fossil fuels but will struggle to also meet forecast increases in power demand owing to the electrification of the global energy system and rising energy consumption in developing countries, he says.

In 2050, the world will need 12 times more clean electricity than is produced today, he says, citing the work of climate author Solomon Goldstein-Rose. “Anything at all that we have which adds on top of the existing picture is a great thing,” Hawker says, “and we should be doing it at maximum speed.”

FT

Health risks of space tourism: Is it responsible to send humans to Mars?




Sat, November 27, 2021

About 60 years ago, humans acquired the technological ability to travel to space. By now, science fiction franchises like "Star Trek" inspired entrepreneurs such as Jeff Bezos to translate their wealth into enterprises of space tourism. Bezos recently expressed the desire to send 1 trillion humans into space in the distant future, because Earth will not be able to accommodate all of them. Unfortunately, humans were not selected by Darwinian evolution to survive for long periods of time in space.

The hazards from energetic particles have been known since the early days of space exploration. On Earth, humans are protected from these charged particles, which originate from the Sun and our Milky Way galaxy. Earth is shielded by its magnetic field and atmosphere. Mars has no magnetic field or atmosphere to shield humans from the damage caused by cosmic radiation.


Human astronauts outside the Earth's magnetic "womb" get zapped by solar energetic particles, mostly during sporadic solar flares that last from minutes to hours. Such flares are prominent when the sun is "active", namely during solar maxima in its 11-year cycle of surface activity. The most energetic solar particles can be deadly. Humans have a better chance of survival on Mars when the Sun is least active, namely during solar minima.

But even if humans avoid the radiation from the Sun, there is an additional risk from Galactic cosmic rays. During a space journey that lasts more than three years, these Galactic particles would be life-threatening as well. The potential cumulative effects from space radiation must be studied thoroughly before sending humans for missions that last more than a few years. Protection could potentially be offered in deep caves under the Lunar or Martian surface.

Our solar system receives only a fraction of the Galactic cosmic rays, thanks to magnetic shielding by the so-called heliosphere, located at a hundred times the Earth-Sun separation, where the Solar wind meets the interstellar medium. The heliosphere was traversed by NASA's Voyager 1 space craft in 2012 and by Voyager 2 in 2018. The instruments onboard these missions revealed that the heliosphere blocks about three-fourths of the galactic cosmic rays.

As of now, scientists are unable to forecast reliably the levels of Galactic cosmic radiation throughout the solar system. The very region that shields the galactic radiation is the one that is least understood.

Space missions, such as Voyager, New Horizons, Interstellar Boundary Explorer and Cassini-Huygens, revealed the frontal extent of the heliosphere and the incoming stream of hydrogen atoms from the galaxy, but the fundamental features of the heliosphere remain unknown. In particular, the global shape and distribution of cosmic radiation are uncertain.

Before sending humans to long space journeys, more resources should be allocated to studying the radiation filtered by the heliosphere. Better understanding of our own environment will also help us forecast whether life exists on Earth-like planets around other stars.

Some habitable planets are protected from energetic particles by their atmosphere and magnetic field, as well as by the analog of our heliosphere, labeled "astrosphere" for other stars. We currently know very little about astrospheres in general. Studies of the heliosphere would help us understand the critical mechanisms that controls the properties and shielding of energetic particles that pose a threat to extraterrestrial life.

The human body is fragile. Humans cannot safely venture to long journeys beyond our immediate vicinity near Earth. Before sending human-astronauts to long expeditions we must ensure that we are not sending them to their death. Ahead of dreaming about a large human population on Mars, as advocated by Elon Musk, we must understand the radiation environment throughout the solar system.

A safe bet, for the time being, is to send our technological kids, in the form of robots like the Perseverance rover or futuristic AI-astronauts. Artificially-made hardware is manufactured to be far more resilient to damage by energetic particles than the human body. And we should be proud of launching our technological products to space as we are of sending our biological kids to explore the world.

Merav Opher is a professor in the Astronomy Department at Boston University. She is currently the William Bentinck-Smith fellow at the Harvard Radcliffe Institute. She is the leading SHIELD, a NASA DRIVE Science as principal investigator. SHIELD is a multi-institutional effort with more than 45 leading scientists across a dozen institutions. She was the chair-elect of the APS Topical Group in Plasma Astrophysics; member of the Decadal Survey in Space Physics of Solar and Heliospheric Panel and the last three NASA Heliophysics Mission Senior Review Panels.

Avi Loeb is a professor of science at Harvard University, head of the Galileo Project, founding director of Harvard University's - Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University from 2011-2020. He chairs the advisory board for the Breakthrough Starshot project and is a former member of the President's Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of "Extraterrestrial: The First Sign of Intelligent Life Beyond Earth" and a co-author of the textbook "Life in the Cosmos."

Why farts in space are dangerous: For a man, it’s a minor odor, but for mankind, it’s a massive smell.

BY ALANIS HAYAL ON NOVEMBER 27, 2021


NASA astronauts have shown that something that most of us do without thinking at least a dozen times a day could endanger astronauts in orbit.

Every day, the average person farts up to 15 times.

It’s not a major concern if you work outside, but it’s more difficult if you work in an office or shop, and it may be fatal if you’re an astronaut.

It is, to begin with, rather antisocial.

Mike Massimino was a member of the Columbia crew in 2002 on a mission to repair the Hubble Space Telescope, and he returned to space in 2009 aboard Columbia’s sister ship Atlantis.

Unpleasant bodily scents do not disappear in the same manner they do on Earth, he noted.

Mike explained to Gizmodo, “Farts have a tendency to linger.””

The airflow isn’t as as strong as it is on Earth.

You need to add airflow to get rid of pollutants and carbon dioxide.”

He argues that astronauts’ digestive systems don’t perform as effectively in zero gravity and that they become “a little choked up.”

When an astronaut smells a fart coming on, they normally want to get to the lavatory, where there is at least a little more ventilation to help break up the stench.

“It’s probably comparable to how it works on Earth,” he continued, “either you do it in private or you make people upset at you.”

Mike cautions that simply having a good time on the International Space Station could lead to “crew conflict.”

“If you fart, the gas stays right there,” says Derrick Pitts of The Franklin Institute in Philadelphia, a space expert.

It doesn’t appear to be getting any better.

“If you fart in zero G, you have a serious problem,” he adds.

Clayton C Anderson, a NASA astronaut who spent 152 days onboard the International Space Station in 2007, acknowledged to receiving complaints about the scents he left laying around the station.

“Just ask a couple members of my staff! So much so that one of my spacewalking (EVA) teammates – who shall remain nameless – would frequently give me unambiguous verbal indicators that my gas was fragrant in a bad sense “On Quora, he admitted it.

Farts in space, on the other hand, imperil more than just a spacecraft full of disgruntled people.

Many of the gases produced naturally by our digestive systems are combustible, therefore a spacecraft fire is extremely deadly.

Five planned space stations for tourists and astronauts

Human population in space could rise in future, as private companies and space agencies look to set up more space stations

In October, Jeff Bezos’ Blue Origin announced plans to build a private space station in Earth orbit, called Orbital Reef. Photo: Blue Origin

Sarwat Nasir

Nov 26, 2021

There has been a continuous presence of humans in space since 2000, when the International Space Station became operational.

Now, as the floating laboratory gets closer to its inevitable retirement, there are questions around what would replace it.

Private companies are looking to commercialise low Earth orbit, with space stations that would welcome tourists, researchers and astronauts.

Meanwhile, government space agencies have increased their focus on the Moon, with Nasa, China and Russia looking to build a lunar base.

The National highlights some of the space stations that were announced by private companies and governments.

Orbital Reef

In October, Jeff Bezos’ Blue Origin announced plans to build a private space station in Earth orbit, called Orbital Reef.

The space tourism company hopes to build a “mixed-use business park” and is promising access to media, tourists, astronauts and researchers.

It is going to be a commercially developed, owned and operated low-Earth orbit station, built in partnership with Boeing, Redwire Space, Sierra Space, Genesis Engineering Solutions and Arizona State University.

“For over sixty years, Nasa and other space agencies have developed orbital space flight and space habitation, setting us up for commercial business to take off in this decade,” Brent Sherwood from Blue Origin said at the time of the announcement.

“We will expand access, lower the cost, and provide all the services and amenities needed to normalise space flight. A vibrant business ecosystem will grow in low Earth orbit, generating new discoveries, new products, new entertainments, and global awareness.”

The plan is to begin operations within this decade, after launching a power system, core module, life habitat and a science module. This would enable the station to host up to 10 people, initially.

Genesis Engineering Solution, an aerospace and technology provider, would supply single-person spacecraft on the station, allowing those on board to go on spacewalks.

Starlab

Less than a week before the Orbital Reef announcement, Nanoracks had unveiled plans of a commercial space station that would aid efforts in scientific research and tourism.

Founded in 2009, Nanoracks is a commercial space company that has sent more than 1,300 research payloads and small satellites to the ISS.

It would include a large inflatable habitat, designed and built by Lockheed Martin, a metallic docking node, a power and propulsion element, a robotic arm for servicing cargo and payloads, a laboratory to host research, science and manufacturing capabilities.Now, it has gone into partnership with Voyager Space, a company into space exploration, and aerospace firm Lockheed Martin to build its first free-flying space station, called Starlab.

Up to four astronauts would be able to occupy the station. The company hopes to begin operations by 2027.

Axiom Station

Space infrastructure company Axiom is planning to launch a commercial module to the ISS that would become its own independent station once the ISS retires.

The station will offer access to researchers, astronauts and tourists. By 2028, the Axiom modules would be ready to detach from the ISS, allowing microgravity research, manufacturing and life support testing.

The first two modules that will be launched would each have four crew quarters.

Axiom also plans to launch the first paying crew to the ISS next year.

Lunar Gateway

Nasa has ambitious plans to build a station in the Moon’s orbit.

Called the Lunar Gateway, the station would host astronauts before they land on the lunar surface, using a human landing system.

It is part of the space agency’s deep space exploration plans, which includes building a sustainable human presence on the Moon under the Artemis programme, and sending astronauts to Mars from there in future.

Plans for the Gateway includes a Habitation and Logistic Outpost, an initial crew cabin that would offer astronauts basic life support and space to prepare for their trip to the lunar surface.

Nasa chose SpaceX to deliver cargo and other supplies to the station.

China-Russia lunar station

Earlier this year, China and Russia unveiled plans to build the International Lunar Research Station.

The proposal involves sending several Chinese and Russian missions to the Moon over a 15-year period.

Rendering of International Lunar Research Station revealed by Chinese and Russian space officials during the third day of the Global Space Exploration Conference in St Petersburg, Russia in June.

Five facilities and nine modules are planned for the station, intended to support long and short missions to the Moon's surface and orbit.

The plan includes a facility that would support round-trip transfer between Earth and the Moon, lunar orbiting, soft landing, take-off on lunar surface and re-entry to Earth.

A long-term support facility on the surface will include a command centre, energy and supply modules, and thermal management.

Designs also include a “hopping robot” and smart mini-rovers that would move around the surface of the Moon.

The plan is to launch six missions by 2025 during phase one of the station’s construction.

It was reported that China is also working on a lander for human Moon missions.

China has astronauts in low Earth orbit who live on Tianhe, the core cabin module of its Tiangong space station.

Updated: November 26th 2021, 9:00 PM

Climate 'overwhelming' driver of Australian bushfires: study

Australia's conservative government has consistently played down the role of climate 

change in the 2019-2020 fires, which cloaked major cities like Sydney in acrid smoke.

Climate change is the "overwhelming factor" driving the country's ever-more intense bushfires, Australian government scientists believe—directly contradicting claims by the country's political leaders.

In a peer-reviewed study, scientists at state agency CSIRO reviewed 90 years' worth of data and concluded climate change was the major influencing factor behind megafires like those that ravaged Australia in 2019-2020.

The experts studied a range of fire risk factors—from the amount of dead vegetation on the ground to moisture, weather and ignition conditions—to see what could be driving catastrophic blazes.

"While all eight drivers of fire activity played varying roles in influencing forest fires, climate was the overwhelming factor driving fire activity," said CSIRO chief climate research scientist Pep Canadell.

The findings were published in the latest issue of scientific journal Nature Communications on November 26.

Australia's conservative government has consistently played down the role of climate change in the 2019-2020 fires, which burned across the southeast coast and cloaked major cities like Sydney in acrid smoke.

Prime Minister Scott Morrison variously insisted that bushfires were normal in Australia or that the issue was forest management—including the removal of debris.

But researchers found that "regression analyzes with modeled fuel loads show no statistically significant relationships with burned area."

Atmospheric patterns like El Nino or La Nina can influence year-to-year changes in the intensity of bushfires, but researchers found nine out of the 11 years when more than 500,000 square kilometers have burned have taken place since 2000 and as global warming has quickened.

They linked those events to "increasingly more dangerous fire weather" like fire-generated thunderstorms and dry lightning "all associated to varying degrees with anthropogenic climate change."

Burned area has increased by 800 percent on average in the last 20 years versus the decades before, the study found.

In recent years Australia has experienced a litany of climate-worsened droughts, bushfires and floods.

But the country's government has avoided setting a short term emissions reduction target and has vowed to remain one of the world's largest coal and gas exporters.

Study: Climate-driven forest fires are on the rise

More information: Josep G. Canadell et al, Multi-decadal increase of forest burned area in Australia is linked to climate change, Nature Communications (2021). DOI: 10.1038/s41467-021-27225-4

Journal information: Nature Communications 

© 2021 AFP