Hiding in the blackness of space is an eerie galaxy that is composed of the best cosmic camouflage a galaxy can get: dark matter.
Roughly 80 percent of the mass of the universe is made up of material that scientists cannot directly observe. Known as dark matter, this bizarre ingredient does not emit light or energy. So why do scientists think it dominates?
Studies of other galaxies in the 1950s first indicated that the universe contained more matter than seen by the naked eye. Support for dark matter has grown, and although no solid direct evidence of dark matter has been detected, there have been strong possibilities in recent years.
The familiar material of the universe, known as baryonic matter, is composed of protons, neutrons and electrons. Dark matter may be made of baryonic or non-baryonic matter. To hold the elements of the universe together, dark matter must make up approximately 80 percent of its matter. [Image Gallery: Dark Matter Across the Universe]
The missing matter could simply be more challenging to detect, made up of regular, baryonic matter. Potential candidates include dim brown dwarfs, white dwarfs and neutrino stars. Supermassive black holes could also be part of the difference. But these hard-to-spot objects would have to play a more dominant role than scientists have observed to make up the missing mass, while other elements suggest that dark matter is more exotic.
Most scientists think that dark matter is composed of non-baryonic matter. The lead candidate, WIMPS(weakly interacting massive particles), have ten to a hundred times the mass of a proton, but their weak interactions with “normal” matter make them difficult to detect. Neutralinos, massive hypothetical particles heavier and slower than neutrinos, are the foremost candidate, though they have yet to be spotted. The smaller neutral axion and the uncharched photinos are also potential placeholders for dark matter.
A third possibility exists — that the laws of gravity that have thus far successfully described the motion of objects within the solar system require revision.
Proving the unseen
If scientists can’t see dark matter, how do they know it exists?
Scientists calculate the mass of large objects in space by studying their motion. Astronomers examining spiral galaxies in the 1950s expected to see material in the center moving faster than on the outer edges. Instead, they found the stars in both locations traveled at the same velocity, indicating the galaxies contained more mass than could be seen. Studies of the gas within elliptical galaxies also indicated a need for more mass than found in visible objects. Clusters of galaxies would fly apart if the only mass they contained were visible to conventional astronomical measurements.
Albert Einstein showed that massive objects in the universe bend and distort light, allowing them to be used as lenses. By studying how light is distorted by galaxy clusters, astronomers have been able to create a map of dark matter in the universe.
All of these methods provide a strong indication that the most of the matter in the universe is something yet unseen.
Dark matter versus dark energy
Although dark matter makes up most of the matter of the universe, it only makes up about a quarter of the composition. The universe is dominated by dark energy.
After the Big Bang, the universe began expanding outward. Scientists once thought that it would eventually run out of the energy, slowing down as gravity pulled the objects inside it together. But studies of distant supernovae revealed that the universe today is expanding faster than it was in the past, not slower, indicating that the expansion is accelerating. This would only be possible if the universe contained enough energy to overcome gravity — dark energy.
Physicists have discovered that gravity and quantum effects disrupt the symmetry of the electromagnetic field, making symmetry impossible in our universe. If true, the work will add insight to the study of the origins of the universe.
GRAVITY AND ELECTROMAGNETISM
New research from physicists at Louisiana State University (LSU) and Universidad de Valencia, Spain, may offer the answer to questions left open by classical theories of electromagnetism. If this new research solves part of this mystery, it may also provide a window into the origins of the universe.
Waves of all kinds, including light, are made of magnetic and electric fields. For around 150 years, scientists have accepted the idea that magnetism and electricity are really just two sides of the same coin. When Michael Faraday spun magnets, generating electricity — and used electrical currents to make magnets spin — the connection seemed obvious. James Clerk Maxwell took the experiments of Faraday and turned them into the classical theory of electromagnetism, which provided a unified framework for studying optics, magnetism, and electricity.
The mystery of electromagnetism lies in the absence of magnetic charges. Maxwell’s theory, referred to as the electric-magnetic duality, rests on a concept of symmetry and assumes that magnets having charges. However, no isolated magnetic charges have ever been observed in nature, and while something that behaves in a similar way has been simulated in laboratories, this is scarcely the same as actual empirical evidence. If magnetic charges don’t exist, then Maxwell’s theory of symmetry is impossible.
Now, LSU’s Ivan Agullo and his team of researchers think they know why these isolated magnetic charges, also called magnetic monopoles, have never been found: gravity and quantum effects disrupt the symmetry of the electromagnetic field.
STUDYING THE UNIVERSE’S BIRTH
This new research challenges many basic scientific premises that may affect other research, including the study of the origins of the universe. Satellites collect data from the Cosmic Microwave Background (CMB), the radiation emitted from the Big Bang and which holds valuable clues about the history of the universe.
“By measuring the CMB, we get precise information on how the Big Bang happened,” Agullo said in the press release.
Until now, scientists analyzing CMB data have assumed that the gravitational field in the universe does not affect the polarization of photons in the CMB. However, this is only true if electromagnetic symmetry exists. If it doesn’t, cosmic evolution may be changing the polarization of the CMB constantly.
Should this research be accurate, scientists will need to analyze CMB data in new ways. The team’s focus for future work will be the identification of just how much the polarization may be changing, and how scientists can adjust their analyses to cope with this new asymmetrical reality.
For decades, scientists have tracked hints of a thread-like structure that ties together galaxies across the universe. Theories, computer models, and indirect observations have indicated that there is a cosmic web of dark matter that connects galaxies and constitutes the large-scale structure of the cosmos. But while the filaments that make up this web are massive, dark matter is incredibly difficult to observe.
Now, researchers have produced what they say is the first composite image of a dark matter filament that connects galaxies together.
“This image moves us beyond predictions to something we can see and measure,” said Mike Hudson, a professor of astronomy at the University of Waterloo in Canada, co-author of a new study published in the Monthly Notices of the Royal Astronomical Society.
Dark matter, an elusive substance that is estimated to make up around 27 percent of the universe, doesn’t give off, reflect, or absorb light. This has made it virtually impossible to detect, except for its effects when it exerts a gravitational tug or when it warps the light of distant galaxies in what is called gravitational lensing.
For their work, Hudson and co-author Seth Epps, who was a master’s student at the University of Waterloo at the time of the research, employed a technique called weak gravitational lensing — a statistical measurement of the slight bends that occur in the path of light passing near mass. The effect produces illustrations of galaxies that appear slightly warped owing to the presence of celestial mass, such as dark matter.
In their paper, they explained that in order to study the weak lensing signal of the dark matter filaments, they required two sets of data: a catalog of galaxy cluster pairs that were lensed, and a catalog of background source galaxies with accurate distance measurements.
They combined lensing data from a multi-year sky survey at the Canada-France-Hawaii Telescope with information from the Sloan Digital Sky Survey that mapped luminous red galaxies (LRGs), which are massive, distant, and very old galaxies.
“LRGs are very bright galaxies,” Hudson told Seeker via email. “They tend to be more massive than the average galaxy and live in more massive dark matter ‘halos.’ It’s reasonable to expect that the filament or bridge between them might also be more massive than the average.”
Hudson and Epps combined or “stacked” more than 23,000 galaxy pairs, all located about 4.5 billion light-years away. This allowed them to create a composite image or map that shows the presence of dark matter between galaxies. Hudson told Seeker that the filament in their “image” is the average of all 23,000 pairs.
“The primary reason that we used these galaxies is that they had precise distances (as measured by another team),” Hudson explained. “These distance measurements allowed us to distinguish between pairs of galaxies that were actual pairs in 3D (meaning both are at the same distance from us) as opposed to two galaxies that appeared close on the sky but were actually at very different distances.”
3D pairs would be physically close to each other and hence, will have a bridge whereas the second group are not physically close to each other, and so would not have a bridge between them. Hudson and Epps said their results show the dark matter filament bridge is strongest between systems less than 40 million light years apart.
“By using this technique, we’re not only able to see that these dark matter filaments in the universe exist, we’re able to see the extent to which these filaments connect galaxies together,” Epps said in a statement.
The Big Bang theory predicts that variations in the density of matter in the very first moments of the universe led the bulk of the matter in the cosmos to condense into a web of tangled filaments. To explain this, astronomer Fritz Zwicky first introduced the concept of dark matter in 1933, when his measurements of galaxies moving within a galaxy cluster showed they must have at least ten times more invisible matter than what is visible.
But it wasn’t until the 1970s that dark matter was taken seriously. Vera Rubin and Kent Ford Jr. mapped the motions of stars within galaxies close to our own Milky Way, and they also concluded that each galaxy had to include enormous amounts of unseen matter, far more than all the visible matter. Later, computer simulations confirmed this and suggested the existence of dark matter, structured like a web, with long filaments that connect to each other at the locations of massive galaxy clusters.
In their paper, Hudson and Epps list dozens of previous studies that have attempted to measure and observe the dark matter web, and they say they hope their stacking techniques to measure the filaments between groups and clusters of galaxies can serve as a foundation for future filament studies. They hope upcoming surveys and telescopes will continue to further our understanding of dark matter.
Particle physicists might seem like a dry bunch, but they have their fun. Why else would there be such a thing as a “strange quark”? When it comes to the fundamental nuclear forces, though, they don’t mess around: the strongest force in nature is known simply as the “strong force,” and it’s the force that literally holds existence together.
Zoom In On The Elementary Particles
Forces Of Nature
Watch And Learn: Videos About Particle Physics To Make You Sound Smart
The Four Fundamental Forces Of Physics Explained
Here they are, in all their glory!
This is the first time atmosphere has ever been detected around a planet with a mass and radius so similar to Earth’s, and that makes it a hugely promising (and exciting) target for researchers searching for signs of extraterrestrial life.
“While this is not the detection of life on another planet, it’s an important step in the right direction: the detection of an atmosphere around the super-Earth GJ 1132b marks the first time that an atmosphere has been detected around an Earth-like planet other than Earth itself,” said lead researcher John Southworthfrom Keele University in the UK.
There’s still a lot to learn about GJ 1132b’s atmosphere, but early observations suggest it could be a “‘water world’ with an atmosphere of hot steam” – AKA, a pretty awesome place to go looking for life.
So far, we know that GJ 1132b has a mass about 1.6 times that of Earth’s, and has roughly 1.4 times its radius – which in terms of exoplanets makes it remarkably similar to our home planet.
But as with all exoplanet discoveries, the researchers are quick to remind the public that the observations to date still really don’t give us much insight into how similar GJ 1132b could be to Earth – or how habitable.
Some bad news upfront is it has an estimated surface temperature of 370 degrees Celsius (698 degrees Fahrenheit), which makes it unlikely that it could host life like us.
And let’s not forget that we’ve recently been burned by the detection of the TRAPPIST-1 ‘sister solar system’ and neighbouring Earth-like planet Proxima b, both of which are unlikely to be the friendly places for life we first thought they were.
Right now, the top strategy for astronomers in the search for life on another planet is to detect the chemical composition of that planet’s atmosphere, looking for certain chemical imbalances that could hint at the presence of living organisms. For example, on Earth, the large amount of oxygen in our atmosphere is that ‘smoking gun’.
We’re a long way off having that much insight into GJ 1132b, but the fact that we’ve detected its atmosphere at all is a good first step.
The planet orbits the not-too-distant red dwarf star Gliese 1132, which Southworth and his team studied using the ESO/MPG telescope in Chile.
They measured the slight dip in brightness across seven wavelengths of light as GJ1132b passed in front of its host star every 1.6 Earth days, in order to get a better idea of the size and composition of the planet.
They were surprised to find that the planet appeared larger when observed in one type of infrared wavelength of light, which suggests that the planet has an atmosphere that’s opaque to these wavelengths.
The team went on to model different possible versions of this atmosphere, and found that an atmosphere rich in water and methane could explain what they were seeing.
Prior to this, the only exoplanets that researchers have detected atmospheres around were planets that were more than eight times more massive than Earth, and gas giants similar to Jupiter.
“With this research, we have taken the first tentative step into studying the atmospheres of smaller, Earth-like, planets,” said Southworth. “The planet is significantly hotter and a bit larger than Earth, so one possibility is that it is a ‘water world’ with an atmosphere of hot steam.”
The type of star GJ 1132b is orbiting also makes the planet of particular interest – its host star is a low-mass red dwarf, which are incredibly common throughout the Universe and are frequently found to host small, Earth-like planets.
But they’ve also been shown to be particularly active, often blasting huge solar flares out at their surrounding planets – something previous research has suggested would evaporate any traces of a planet’s atmosphere.
But the new discovery suggests that an atmosphere is possible of enduring this bombardment for billions of years without being destroyed – which opens up the possibility that thousands more planets orbiting low-mass stars could potentially harbour atmospheres.
“Given the huge number of very low-mass stars and planets, this could mean that the conditions suitable for life are common in the Universe,” a press release explains.
We still have a lot to learn about GJ 1132b, and hopefully we’ll have some more answers soon – the new discovery makes it one of the highest-priority targets to be studied by instruments such as the Hubble Space Telescope, the Very Large Telescope, and the James Webb Space Telescope, which is scheduled to launch in 2018.
NASA’s been in a slump lately. The International Space Station (ISS) is going to be retired somewhere in 2024-2028. It doesn’t even have a rocket right now to send anything up there, anyway. Not after retiring the space shuttle. The agency has been concentrating for six years on developing its new Space Launch System (SLS), to run missions to other parts of our solar system. You can argue that the SLS will be worth the wait. These will be the most powerful, heavy rockets NASA’s ever built.
Of course, there is a planned mission to land humans on Mars by 2033. But that’s far off, and the details have been fuzzy. That’s why space heads stood up and took notice recently, when NASA’s chief of human spaceflight, Bill Gerstenmaier, gave a presentation. Gerstenmaier revealed to the agency’s advisory council tentative plans for a lunar space station.
As part of its NextSTEP program, NASA has employed six companies to help it design the next generation of stations and vehicles. Boeing just announced its contribution—the Deep Space Gateway lunar station. Now NASA’s vision is starting to become clearer.
At the agency’s presentation, Gerstenmaier outlined plans to build and launch the station, which will allow Deep Space Transport (DST) craft to dock, aiding them in longer range missions, including to Mars. NASA’s press release called the station a place that “offers a true deep space environment,” for humans to get acclimated.
Deep Space Gateway will allow for more lunar missions as well, including robotic ones. The advantage is, if something goes wrong, crew members can try and make it back home again, a luxury not afforded to those headed for Mars.
Boeing Deep Space Gateway. Boeing.
Though there aren’t any hard dates yet, NASA plans to stagger missions, sending off one each year. It wants to work out how to coordinate the SLS, Orion, and the International Space Station (ISS), to support missions farther afield. Later on, they plan to set up a permanent installation in cislunar orbit (or near the moon).
The lunar station will be much smaller than the ISS, consisting of a power bus, a small habitat for the crew, a docking station, airlock, one research module, and one logistics one. For propulsion, they plan to use high power electric engines, a technology NASA itself has developed. This way, the station can position itself in one of a number of different orbits around the moon.
NASA is currently creating SLS and Orion spacecraft for the first two missions. Exploration Mission 1 (EM–1) should take place sometime next year. This will be a crewless journey. On other fronts, propulsion and habitation for the lunar station are in development. On board the ISS, life support systems and “related technologies,” are being tested.
From 2023 to 2026, NASA plans to send up pieces of and assemble the gateway. These missions will include four astronauts and should last between eight and 21 days. By the end of the 2020s, a one year mission will commence, to test systems required to travel to Mars, and elsewhere.
They’ll run experiments in the vicinity of the moon, in order to “build confidence that long-duration, distant human missions can be safely conducted with independence from Earth.” That’s according to a statement on NASA’s website. Not only is the agency starting to build up infrastructure, they foresee challenges both technical and human. This space station will help develop strategies to overcome them.
How well can humans live in deep space? That isn’t really something that’s ever been tested. Astronauts and later colonists will need to endure long journeys aboard a Deep Space Transport (DST) craft, also being developed by Boeing. Somewhere around 2029, NASA plans to send astronauts aboard one of these, for a total of 300-400 days, somewhere near our moon.
Boeing Deep Space Transit (DST) Vehicle. Boeing.
The long-term goal is reusable craft that can ferry people to places such as Mars, return to the gateway, refuel, get serviced, and go back out again. SpaceX recently proved it possible to reuse rockets, in yet another successful landing, this time including a redeployment. Reusability will soon become the mainstay of space exploration, which brings the cost down exponentially.
This isn’t only a US mission. Besides private companies, other countries can lend a hand. Partners may offer hardware or “supplemental resources.” We’ve just dipped our toes in outer space’s vast waters, as a species, and had a few jaunts into the shallow end. Spreading out and really exploring the solar system is a feat beyond anything humanity has ever done.
These efforts could ultimately open up space to commercial ventures. And the time is nigh. The world will soon be running out of the precious minerals needed for consumer electronics. Space if full of them. In fact, it’s been predicted that asteroid mining will bear the world’s first trillionaire.
Our newly discovered ‘sister solar system’ – a seven-planet conga line orbiting an ultra-cool dwarf star called TRAPPIST-1 – has been hailed as a potentially habitable pocket of the Universe, flush with liquid water and temperate climates, and only 39 light-years away.
But the closer we look, the less ‘alien-friendly’ this star system appears, with scientists now finding that TRAPPIST-1 is so volatile, either its three ‘Earth-like’ planets have one hell of a magnetosphere, or we’re looking at yet another set of uninhabitable worlds.
A team led by astronomer Krisztián Vida from Konkoly Observatory in Hungary has been analysing luminosity patterns in the raw photometric data of TRAPPIST-1, obtained during the K2 mission of NASA’s Kepler space telescope.
Over an 80-day period, they clocked 42 high-energy flares blasting from TRAPPIST-1, including five that were ‘multi-peaked’ eruptions, meaning they gave off several bursts of energy in one go.
The strongest eruption the team identified was about as powerful as the largest flare we’ve ever witnessed from our own Sun – the infamous Carrington Event of 1859, which if it happened today, would devastate global communication systems.
But if life on Earth can withstand flares like the Carrington Event, why can’t hypothetical aliens on TRAPPIST-1’s three Earth-like planets?
The first thing to consider is that the average time between these flares was just 28 hours, so we’re talking serious and near-constant bombardment here.
According to a separate study released last year, it would take 30,000 years for a planet’s atmosphere to stablise after one of these powerful flares – so they’re not getting much done in just 28 hours.
On top of all of that, the planets in the TRAPPIST-1 star system are much closer to their star than we are to our Sun.
That means this relentless bombardment would likely destroy any stability in their atmospheres, making it very difficult for even the most primitive life to get a foothold.
“The frequent strong flares of TRAPPIST-1 are probably disadvantageous for hosting life on the orbiting exoplanets, as the atmospheres of the exoplanets are constantly altered and cannot return to a steady state,” the team concludes.
Just to drive this depressing point home even further, Evan Gough over at Universe Today points out that Earth’s robust magnetic field protects us from the worst parts of the Sun’s flares, but it’s unlikely the TRAPPIST-1 planets have the same shield up.
“How could the TRAPPIST planets produce a magnetosphere powerful enough to protect their atmosphere?”
So things aren’t looking so great for our sister solar system.
And while we’ve pretty much gotten used to the emotional roller coaster that is the search for life elsewhere in the Universe, this is a tough one, because remember that Google Doodle of our new planet friends?
They just look like such a cool hang.
One thing to keep in mind is that the study is still undergoing peer-review, so the results might be subject to change.
But if taken alongside previous studies that have already brought the system’s habitability into question, we might have to reconsider those awesome NASA travel posters, and come up with something more… Hellscapey.
For almost a decade now, scientists have been trying to decode the origin of some of the most mysterious and explosive signals in the Universe – fast radio bursts (FRBs).
Lasting only milliseconds, these bursts of energy are about a billion times more luminous than anything we’ve ever seen in our own galaxy, and seem to be travelling across vast distances. But despite having detected more than 20 of them, scientists still aren’t sure where they’re coming from, or what causes them. Now researchers are one step closer by ruling out any source on Earth.
There are still several hypotheses out there that need to be ruled out before we can say for sure where FRBs do come from – perhaps the most bizarre one put forward by Harvard scientists last month is that the FRBs could actually be alien signals.
But the fact that we now know the answer lies in space is a big deal. It might sound obvious, but let’s not forget that back in 1998, researchers thought they had discovered a new type of radio signal coming from space, only to figure out 17 years later that it was coming from a microwave oven in their research facility.
The reason the origin of these radio signals is so hard to nail down is that we often find them using single-dish radio telescopes, which can ‘hear’ a lot without providing much perspective on where it’s coming from.
“Conventional single dish radio telescopes have difficulty establishing that transmissions originate beyond the Earth’s atmosphere,” said one of the researchers on the latest study, Chris Flynn from Swinburne University of Technology in Australia.
To overcome this problem and rule out terrestrial interference as the source of FRBs once and for all, the researchers used the Molonglo telescope in the Australian Capital Territory (ACT), which has a collecting area of around 18,000 square metres (194,000 square feet).
This huge collection area means the telescope is ideal for picking up FRBs, but back in 2013, the team also realised that because of its architecture, it’s not possible for it to detect any signals coming from within our atmosphere.
Eventually, they uncovered three new FRB signals in the telescope’s data, which matched perfect with the signals we’ve picked up before – indicating that they couldn’t possibly be coming from Earth.
Their conclusions back up findings from earlier this year, when researchers were able to pinpoint the source of a FRB to a tiny dwarf galaxy more than 3 billion light-years from Earth.
But for now, the sources of the three newly detected FRBs remain relatively mysterious, except for the fact that they’re not of this world – the data suggest they’re coming from the direction of the constellations Puppis and Hydra (signified by the three red stars below):
The Molonglo telescope is now being updated with the hope that it might be able to provide some more insight in future – hopefully even going as far as pinpointing specific galactic origins.
“Figuring out where the bursts come from is the key to understanding what makes them. Only one burst has been linked to a specific galaxy,” said lead researcher Manisha Caleb.
“We expect Molonglo will do this for many more bursts.”
Space is full of eye candy: exploding stars, nebulas of every shape and size, bizarre alien worlds. Though few will ever have the chance to see these breathtaking sights in person, it just got even easier to feed your space needs online thanks to a new, searchable database from NASA.
The site is easy to search and browse, and lets you look at the agency’s newest uploads and the most popular images. Trending now are the most recent “blue marble” photo, mind-boggling nebulaeglimpsed by the Spitzer Space Telescope last year, a waving astronaut mid spacewalk, and this inexplicably majestic photo of a baby owl.
There’s a catch: In a press release, NASA warns would-be browsers that its site is “not comprehensive,” but rather showcases the best the agency has to offer from its gigantic archive. That’s okay, though—with over 140,000 pictures to gawk at and download, there’s plenty to keep you occupied. And since NASA constantly updates its publicly available images with both new and archival holdings, you’re unlikely to get bored any time soon.
It’s not the first time the space agency has delighted the public with vast releases of information. Just this month, NASA unleashed its entire 2017-18 software catalog at NASA Software, which lets the public use NASA-developed code for free. Offerings include the Earth Global Reference Atmospheric Model, which lets users model things like temperature and wind, and an augmented reality iPad program called NASA Flywheel on the off chance that you’re working on ways to better store energy produced by the rotating cylinders called flywheels.
NASA isn’t just serious about space—the agency is also committed to keeping the public up to date on what it’s doing, making results of NASA-funded projects available to the public.
So go ahead: Soak up some space.