Gravity waves detected at last!

Scientists finally discover gravitational waves that were predicted a century ago.

A very special burst of waves from deep space has forever changed the way we look at the universe. These aren’t water waves or waves of light. They are gravity waves, tiny ripples produced by massive objects moving very quickly.

Two black holes produced the newly reported waves when they collided at some point roughly 1.3 billion years ago. Black holes are massive objects that trap light because their gravity is so strong.

Scientists announced the long-awaited discovery of these waves on February 11. That was a century after the famous physicist Albert Einstein first predicted gravity waves would exist. They are also describing their data in a paper published February 11 in Physical Review Letters. 

"It's the first time the universe has spoken to us through gravitational waves," LIGO laboratory executive director David Reitze said at a press conference February 11. "As we open a new window on astronomy, we may see things we never saw before."

Their discovery now gives scientists a new tool for studying the universe. Astronomers need these tools because not everything in the universe can be seen through a telescope. Stars, galaxies and other bright objects emit light that travels to Earth. But black holes are truly black. They don’t emit light, so telescopes can’t see them.

“Gravitational waves allow us to look at the universe not just with light but with gravity,” says Shane Larson. He’s an astrophysicist at Northwestern University in Evanston, Ill.

The discovery immediately becomes a likely candidate for a Nobel Prize. And that's not just because it ties a neat bow around decades of evidence supporting a major prediction by Einstein. In 1916, he came up with the idea for gravitational waves, also called gravity waves. He had just introduced his famous theory of general relativity. That theory says that objects with mass will curve space, similar to how a person standing on a trampoline will bend the fabric. The bending of space changes the motion of nearby objects. For example, the sun’s mass forces Earth to orbit the star in an ellipse, not just move in a straight line.

Collecting trash in space

A satellite that gets rid of space junk could help prevent devastating collisions in Earth orbit.

Satellites play big roles in modern life. Some look downward to monitor environmental conditions on Earth. Others look outward in search of major solar flares that can disrupt the transmission of electrical power to homes and businesses. Some spy on our enemies. Others relay communications around the globe. But all of these million-dollar marvels of technology can be knocked out by a collision with space junk — debris from satellites and other Earthly technology orbiting high above the planet. Now, a teen from Jordan has designed a satellite to chase down space junk, collect it and then dispose of it.

NASA is the U.S. space agency. It and other organizations are tracking about 500,000 pieces of space junk that are currently orbiting Earth. Many come from satellites or rockets that have blown up and shattered. The objects being tracked are the size of a marble or larger. About 20,000 are at least the size of a softball (some are as large as a refrigerator). Most are too small to detect from Earth’s surface. In all, some 100 million pieces of debris likely orbit Earth today, says 15-year-old Dana Arabiyat. She attends Alridwan Schools in Amman, Jordan.

Even bits of space junk as small as flecks of paint pose a threat, says Dana. That’s because this debris orbits our planet at speeds up to some 28,200 kilometers per hour (17,500 miles per hour). That’s about 7.8 kilometers per second! Such blistering speed explains why tiny paint flecks have chipped the windshields of space shuttles so badly that they needed to be replaced.

Researchers have come up with many ideas for getting rid of space junk. Some have suggested vaporizing small bits with lasers. Others have proposed launching satellites to collect the debris. Dana’s design falls into this category.

Here’s how hers would work: A radar system aboard the satellite would scan for and find a piece of space junk. Then, thrusters would change the satellite’s orbit so that it could chase down the errant object. As the satellite closed in on its prey, cameras would keep it on target.

Intergalactic lessons: five creative ways to teach about space

Create your own big bang in the classroom with our lesson ideas, including making edible meterorites and studying real lunar rocks.

When Apollo 11 astronauts Neil Armstrong and Buzz Aldrin landed on the dusty surface of the moon, Armstrong summed up the epochal event with the famous words “that’s one small step for man, one giant leap for mankind”.

The first moon landing will be remembered for centuries to come and this summer (Monday 20 July 2015) marks 46 years since it happened.

The anniversary is a great launching pad for teaching about outer space. We’ve gathered a few creative intergalactic lesson plans below – including edible meteorites and studying real lunar rocks. Our list isn’t exhaustive, however, so feel free to offer your own ideas in the comments thread below, or tweet us your favourites @GuardianTeach.

Borrow the moon

Get engagement levels soaring by bringing in real moon rock. The Science & Technology Facilities Council loans out moon rock, brought back to Earth by Nasa’s Apollo astronauts in the late 1960s and early 1970s, free of charge.

Advice on the website says that teachers should reserve samples four months in advance, and each loan comes with a wide range of support materials including books and DVDs. For example, as part of the Earth science unit at key stages 2 and 3 you can use the rocks to hold a talk exploring what lunar idioms and expressions mean. Teach about the differences and similarities between the Earth and the moon, as well as whether humans could survive there. There are plenty of ideas here on how to use the samples with secondary students.

Edible meteorites

Explore chondrules and fusion crust by making edible meteorites from peanut brittle and chocolate brownies. This resource, designed by Nasa, is aimed at 10- and 14-year-olds (fifth to eighth grades) in the US to help teaching the exploring meteorite mysteries unit. It can easily be adapted for other curriculums, however, including the Earth science unit in the UK.

Water discovered in a small, warm exoplanet’s atmosphere for first time

The planet is a ball of gas with surface temperatures of 600C, but future studies of alien atmospheres may reveal signs of life.

 

 

Astronomers have detected water vapour in the atmosphere of a planet that orbits a star far beyond our solar system.

Observations of the Neptune-sized planet, which lies 120 light years from Earth in the constellation of Cygnus, revealed that its atmosphere was mostly hydrogen with around 25% made up from water vapour.

Until now, researchers have been frustrated in their efforts to study the atmospheres of planets much smaller than Jupiter because their skies were thick with clouds. The problem was so persistent that astronomers had begun to think that all warm, small planets formed with substantial cloud cover.

But writing in the journal Nature, scientists in the US describe how they found a Neptune-sized planet with cloud-free skies, enabling them to make detailed measurements of a small planet’s atmosphere for the first time.

The planet, named HAT-P-11b, is about four times the diameter of Earth. It orbits so close to its star that surface temperatures reach more than 600C and a year passes in five Earth days. Like our own Neptune, the planet lacks a rocky surface – it’s a ball of gas – and is thought to be lifeless.

Scientists from the University of Maryland used Hubble’s wide field camera to analyse light from HAT-P-11b’s host star through the planet’s atmosphere. They found that light with a wavelength of 1.4 micrometres was absorbed, matching the absorption spectrum of water molecules.

“Although this planet is not classically habitable, it reveals to us that when we find Earth 2.0, we will be able to use this technique, transmission spectroscopy, to understand its atmosphere and determine the quality of life available on its shores,” said Jonathan Fraine, a graduate student and first author on the study.

What are asteroids?

Unless they’re ‘trojans,’ most of these space rocks fly in a belt between the orbits of Mars and Jupiter.

 
The solar system contains millions of asteroids. They may be round or oblong. Some have even stranger shapes, as though molded in play dough and left in space to harden. All are made from the same stuff as the planets. However, unlike rocks on Earth, those that make up asteroids have not been shaped by erosion, heat or intense pressure.

All asteroids are fairly small. Their diameters tend to range from less than a kilometer (a little more than half a mile across) to nearly 1,000 kilometers (621 miles across). Together, all of the asteroids in our solar system have a combined mass that is less than that of Earth’s moon.

Some asteroids resemble small planets. More than 150 of them have their own moon. Some even have two. Still others orbit with a companion asteroid; these pairs race circles around each other as they orbit the sun.

The orbits of most fall in a swath of space between Mars and Jupiter. It’s known, naturally enough, as the asteroid belt. But that's still a lonely neighborhood: An individual asteroid is usually at least a kilometer (0.6 mile) away from its nearest neighbor.

Asteroids called trojans don't inhabit the belt. These rocks may follow a larger planet's orbit around the sun. Scientists have identified nearly 6,000 trojans that follow along in Jupiter's orbit. Earth has only one known trojan.

Astronomers Find Slow-Cooked Diamond the Size of Earth

About 900 light-years away, an ancient white dwarf star has cooled into a crystallized chunk of carbon — a diamond. But this isn’t just any old diamond hiding in space: It’s the size of Earth, and it’s 11 billion years old.

The diamond-star, described in a study published in The Astrophysical Journal, is among the coldest white dwarfs astronomers have found. In fact, it’s so cool and dim that it can’t even be seen — its feeble light isn’t nearly powerful enough to pierce the darkness of the cosmos, even from relatively nearby.

Instead, teams inferred the presence of the crystallized dwarf based on the way its gravity perturbs the normally steady radio pulses coming from a spinning companion star.

Yep, the system gets even cooler. The dwarf is orbiting a pulsar — a rapidly rotating neutron star — known by the charismatic moniker PSR J2222-0137. The system is similar to another that was described in 2011, with a crystallized white dwarf orbiting a pulsar — but this new diamond is bigger (there’s also a planet hypothesized to be somewhat diamond-like).

If you were to look in the sky in the direction of the constellation Aquarius, you’d be looking in roughly the right direction to see the system, which is actually a pair of dead stars: The spinning neutron star is the extremely dense remnant of a formerly huge star that ended its life in a supernova. A white dwarf is all that remains of a formerly Sun-like star, contracted into a clump the size of Earth. Left on their own, dwarfs will slowly cool and fade to black over billions of years (but sometimes, with the help of a stellar companion, they can detonate and create dazzling supernovas the outshine entire galaxies).

“White Holes” Could Exist—But That Doesn't Mean They Do

A black hole is a one-way door to oblivion. According to general relativity, once anything crosses its boundary—the event horizon—it cannot return to the outside. For that particle, the black hole is the entire future.

We’ll never actually get a chance to see the particle live out that destiny: Any light the particle emits (which would be the only way for us to observe its death plunge) will be stretched to longer and longer wavelengths with correspondingly less energy, until it fades beyond detectability. In fact, the story is even more strange. If we observe the particle falling in, we could never live long enough to see it reach the event horizon. The extreme gravity of the black hole makes time appear, to an outside observer, to go more slowly there; in fact, the particle would seem to us to take infinite time to reach the event horizon. That’s true even though from the particle’s reference frame, it crosses the event horizon unremarkably, with no unusual effects on time and space.

If a black hole is a one-way door to oblivion, you might wonder if there is any way to go the other way through the door—and it’s a good question. General relativity, which has been our standard theory of gravity for nearly 100 years, makes no distinction between past and future, time running forward and time running backward. (See physicist Sean Carroll discuss the time-symmetry of physics in his interview with Nautilus.) Newtonian physics also is time-symmetric in the same way. So the idea of “white holes”—black holes reversed in time—does make theoretical sense.

Nasa Kepler telescope discovers planet believed to be most Earth-like yet found

Kepler-186f is 10% bigger and occupies its star's 'habitable zone' where temperatures would allow liquid surface water.

A newly discovered planet may be the most Earth-like yet found in another solar system, scientists believe.

Kepler-186f is almost the same size as the Earth and occupies its star's "habitable zone" where temperatures are mild enough to allow liquid surface water.

If the planet has lakes or oceans, it would increase the chances of life evolving there.

But anything living on the world may have to withstand extra large doses of radiation from its active sun, Kepler-186.

The find is described in the journal Science as "a landmark on the road to discovering habitable planets".

Smaller and cooler than our sun, Kepler-186 is classified as an M-dwarf star, is 795 light years away and is orbited by five known planets.

Kepler-186f, the latest to be discovered, is the outermost plant in the system.

The planet was found by astronomers scouring the Milky Way galaxy for potentially habitable worlds

What a flexed BICEP tells us about the big bang

The cosmological community is bubbling with the news that the BICEP2 experiment may have detected gravitational waves through measuring the radiation left over from the big bang.

If the findings are correct, we will have the most convincing evidence to date that very early on, the universe experienced a phase of extremely rapid expansion known as “inflation”, during which a very small region was stretched to an enormous size, becoming bigger than our observable universe.

We’ll also have a direct window into understanding particle physics at incredibly high energies and, in particular, the period of “grand unification”. This is far beyond what is possible to probe in particle experiments like the Large Hadron Collider at CERN.

The big bang model says our universe is expanding and, as it does, it is slowly cooling down. Turning back the clock, this means that when the universe was much younger, it was also much hotter. The cosmic microwave background, which BICEP2 was probing, is radiation left over from this hotter epoch and provides the best evidence we have that the big bang actually happened.

Germans: 'We've found second solar system'

Photo: DPA. The Germans believe the new solar system is similar to our own.

A team of German scientists claim to have discovered a “second solar system” made up of seven planets orbiting a star similar to our own. 

The astrophysicists at the German Aerospace Centre (DLR) said on Monday they had discovered “the most extensive planetary system to date.”

They have found seven planets circling a star called KOI-351 – more than in other known planetary systems.

A statement on the DLR’s website said the planets were arranged in a similar fashion to our solar system with smaller rocky planets near the star and giant gas planets further away.