Tag Archives: big bang

Blue Galaxy Could Hold Clues To The Origin Of The Universe

Looking for clues about the early universe is often like the proverbialneedle-in-a-haystack, but once in a while astronomers are able to spot objects thatcan open new doors into the distant past.

This is the case of AGC 198691, a small blue galaxy located 30 million light-years away in the constellation of Leo Minor. The object has the smallest fraction of heavy elementsreferred to as metals in astronomyever seen in a galaxy, indicating that its material hasnt changed much since the Big Bang. A paper describing the discovery was published in the Astrophysical Journal.

“Finding the most metal-poor galaxy ever is exciting since it could help contribute to a quantitative test of the Big Bang,” Professor John J. Salzer, of Indiana University andsenior author of the paper, said in a statement.”There are relatively few ways to explore conditions at the birth of the universe, but low-metal galaxies are among the most promising.”

The metals like carbon, oxygen, and so onare produced by stars and spread throughout interstellar space by supernovae. AGC 198691 has just1.3 percent the metallicityof the Sun, a sign that very little star formation has happened since its formation.

Without much “contamination,”the composition of the galaxy, which has been nicknamed Leoncino (Italian for “little lion”), can be used to compare whether the predicted abundance of primordial hydrogen and helium matches with the observations.

Leoncinos uniqueness doesnt stop at its low metallicity. The galaxy is a “dwarf,” about 1,000 light-years across and made of a few million stars. An average system like the Milky Way is about 100 times wider and containsbetween 200 and 400 billion stars. Although Leoncino has some recently formed stars, responsible for its blue color, the galaxy has the lowest luminosity ever observed for this kind of object.

“We’re eager to continue to explore this mysterious galaxy,” added Salzer. “Low-metal-abundance galaxies are extremely rare, so we want to learn everything we can.”

The team is pursuing follow-up observations with several instruments, including the Hubble Space Telescope. A better understating of these galaxies will lay the groundwork for the potential detection of even more metal-poorobjects by the next generation of observatories.

Read more: http://www.iflscience.com/space/blue-galaxy-gives-clues-about-early-universe

10 Greatest Unsolved Mysteries In Physics

It can seem like an uphill challenge to try to understand the universe around us. We have found many answers to the mysteries in our world: how planets orbit the Sun, why an apple falls from a branch to the ground, and why the sky appearsblue. The quest to uncover all ofthe secrets of the universe is guaranteed to be filled with difficult challenges, unimaginable problems and a mountain of ingenuity neededto overcome them.

Many physicists have already wrestled with the riddles of existence, but there are many more conundrums to solve. Get ready for the ten greatest unsolved mysteries of physics… the enigmas that have evaded the most eminent mindsthe world has ever known.

Dark energy

We can’t see it andwe can’t feel it, but we can test for it, and nobody knows what it is. In spite of this, scientists think that dark energy makes up around 70% of the universe. It was imagined to explain why galaxies don’t just drift apart but instead accelerate away from each other. You can think of it as a repulsive gravity that pushes matter apart. How it works, however, is still a mystery.

Dark matter

The other “dark” substance in our universe. Dark matter, like dark energy, cannot be seen or felt. This elusive substance has some differences to dark energy though; the only way that we have observed it is indirectly. We know that there must be more matter in the universe than we can see becausewe can measure its gravitational effects, but no one knows exactly what makes up this mysterious stuff.

It’s a wave… it’s a particle!

Rays of light have a split personality. They create interference patterns that are typical of waves. They reflect offsurfaces, suggesting that they could be a wave or a particle, or both at the same time. They can also be used to liberate electrons from their shells: something that indicates that they are particles. But how does light determine whether it acts as a particle or a wave?

Time, the onwardmarch

We only get older, not younger. Trees only get taller; they don’t return to acorns. Our Sun only ever uses up its fuel, never returning to a coolball of hydrogen gas. Time only goes in one direction…but why is it impossible for us to reverse the clocks?

We are living in a hologram

This one boggles the mind. The universe, everything we see and feel and experience, may actually have two spatial dimensions. Think of a 2D hologram, like the one on the back of a credit card: it can have all of the information of a 3D image but in only two dimensions. Some scientists have postulated that our universe is like the hologram on your credit cards: space seems like it has three dimensions, but it may turn out that all we are seeing is a projection from a 2D universe outside of our perception.

Matter and antimatter

There is a definite discrepancy between the ratios of these two substances. There was supposed to be an equal amount of ordinary matter and antimatter particles with the same mass but opposite chargein the early universe, but now the universe is overwhelmed with regular matter. Many theories have been thrown around, for examplethat particle genesis favored one way of creating matter, but nothing conclusive has popped up. The mystery of how matter “won” over antimatter may be revealed in the newly-upgradedLarge Hadron Colliderat CERN.

The lifetime of the universe

This mystery,the endof the universe,might not keep you up at night, but it will certainly be of concern to beings alive far into the future.This epiceventispredicted to occur inabout 10 billion years. Two opposing theories are the Big Crunch and the Big Rip. Neither of these outcomes sound terribly fun. The big crunch is the opposite of the Big Bang all of the pieces of matter in the universe will stop accelerating away from each other and start accelerating towardeach other. A boiling collision of all ofthe matter in the universe ensues (and mankind is unlikely to survive that). The Big Rip is where all of the pieces of matter in the universe continue to accelerate away from each other, faster and faster until eventually space-time moves so fast that it rips atoms apart(mankind is also unlikely to survive that one).

These two possibilities aren’t the only possible outcomes for the universe sadly it seems unlikely that our generation will ever know its fate.

Why can’t we imagine four dimensions?

We little humans struggle to envision a world with four spatial dimensions. Some theories (such as string theory) need as many as eleven dimensions to be hypothetically possible. If string theory turned out to be correct, we’d have to figure out how there are sixmissing dimensions tangled up in our reality. I can feel a headache coming on…

Why does light have a universal speed limit?

c, the speed of light constant, is valued at 3×108meters persecond. But whythis figureand not, for example,4×1020m/s?Is it a random digit pulled out of a bag of numbers when a new universe explodes into existance? It’s currently impossible to know why the speed of light is the speed that it is… all we know is that our universe couldn’t exist without this limit.

Unifying the big and the small

Everything big, like stars and black holes, is made up of small things: particles. Einstein’s laws of relativity govern the very big, while quantum mechanics is king in the realm of the very small. But physicists can’t seem to jam the two theories together. The trouble is that gravity just doesn’t appear to work on the nanoscopic scale. And bizarrequantum effects, like quantum tunneling (whereby an atom can “tunnel” through an otherwise impenetrable boundary), can’t be applied to planets or stars. Your eyes would likely pop if the Moon suddenly “tunneled” through the Earth. It seems barmy that there would be one theory for everything big and another for everything small. Some scientists are trying to tackle this problem, and even making headway, but the missing link is still incredibly elusive.

Read more: http://www.iflscience.com/physics/greatest-mysteries-physics

Planck Reveals Most Detailed Map Yet Of The Milky Way’s Magnetic Field

In a collaborative effort, astrophysicists have used data collected from the Planck Space Telescope to generate the most detailed map of our galaxy’s magnetic field yet, which could further our knowledge of the very early universe. The team that produced the map includes scientists from the University of British Columbia and the Canadian Institute for Astrophysics (CITA) at the University of Toronto. The results are described in four forthcoming papers within the journal Astronomy and Astrophysics.

Since its discovery in 1964, scientists have been measuring the Cosmic Microwave Background (CMB) in order to find out more about the birth and evolution of the universe. The CMB is the afterglow of the Big Bang and dates from around 380,000 years after this event. The European Space Agency’s Planck Space Telescope, which was launched in 2009, has given us the most comprehensive picture of the CMB yet, but that’s not all it can be used for.

Planck is able to pick up light from tiny dust particles within our galaxy and can determine the directionality of the vibrations of these light waves, which is called polarization. This information can then be used to deduce the orientation of the magnetic field lines.

According to Douglas Scott, an astrophysicist at the University of British Columbia, the magnetic field of the Milky Way is important for investigating the many phenomena within it. “Planck has given us the most detailed picture of it yet,” he says.

“Dust is often overlooked but it contains the stuff from which terrestrial planets and life form,” said Professor Peter Martin, CITA, who studies dust in the Milky Way. “So by probing the dust, Planck helps us understand the complex history of the galaxy as well as the life within it.”

Planck data to be released later this year will help scientists confidently distinguish signal from the Milky Way from the polarized CMB signal, which will be very handy for those investigating the birth and evolution of the universe. It should also further our knowledge of the universe from as early as one second after the Big Bang to the time when the first stars were being born.

“These results help us lift the veil of emissions from these tiny but pervasive Galactic dust grains which obscure a Planck goal of peering into the earliest moments of the Big Bang to find evidence for gravitational waves created in that epoch,” says CITA Professor J. Richard Bond

Read more: http://www.iflscience.com/space/planck-reveals-most-detailed-map-yet-milky-ways-magnetic-field

Gravity Saved the Universe After the Big Bang

During the accelerated expansion of the early universe, the production of the Higgs boson—the elementary particle responsible for giving mass to all particles—should have led to instability, followed by collapse. At least that’s what some recent studies suggest. 

But the universe didn’t collapse immediately after the Big Bang, and now researchers think they know why. The answer isn’t some new physics that we have yet to understand: It’s quite simply, gravity. The spacetime curvature (gravity, in effect) provided the stability needed for the universe to survive early expansion, according to a new study published in Physical Review Letters this week.

An international team led by Matti Henrikki Herranen from the University of Copenhagen studied the interaction between the Higgs particle and gravity, and how it varies with energy. Even a small interaction, they found, would be enough to stabilize the universe against decay. 

“The Standard Model of particle physics, which scientists use to explain elementary particles and their interactions, has so far not provided an answer to why the universe did not collapse following the Big Bang,” study co-author Arttu Rajantie of Imperial College London says in a news release. “Our research investigates the last unknown parameter in the Standard Model—the interaction between the Higgs particle and gravity.”

He adds: “This parameter cannot be measured in particle accelerator experiments, but it has a big effect on the Higgs instability during inflation. Even a relatively small value is enough to explain the survival of the universe without any new physics!” Here’s a timeline of the universe: 

Next, the team wants to look at this interaction in more detail using cosmological observations from current and future European Space Agency measurements of cosmic microwave background radiation (above) and gravitational waves. The cosmic microwave background is a snapshot of the oldest light in the universe, back when it was just 380,000 years old. The observations could help explain the effect that their interaction would have had on the development of the early universe. “If we are able to do that,” Rajantie says, “we will have supplied the last unknown number in the Standard Model of particle physics.” 

Images: D. Ducros, ESA and the Planck Collaboration (top), NASA/WMAP Science Team via Phys.org (middle)

Photo Gallery

Read more: http://www.iflscience.com/physics/gravity-saved-universe-after-big-bang