Astronomers have found evidence of a giant void that could be the largest known structure in the universe. The “supervoid” solves a controversial cosmic puzzle: it explains the origin of a large and anomalously cold region of the sky. However, future observations are needed to confirm the discovery and determine whether the void is unique.
The so-called cold spot can be seen in maps of the Cosmic Microwave Background (CMB), which is the radiation left over from the birth of the universe. It was first discovered by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) in 2004 and confirmed by ESA’s Planck Satellite. For more than a decade, astronomers have failed to explain its existence. But there has been no shortage of suggestions, with unproven and controversial theories being put forward including imprints of parallel universes, called the multiverse theory, and exotic physics in the early universe.
Now an international team of astronomers led by Istvan Szapudi of the Institute for Astronomy at The University of Hawaii at Manoa have found evidence for one of the theories: a supervoid, in which the density of galaxies is much lower than usual in the known universe.
It is 50 years since humans first encountered space – not Sputnik’s first orbit, nor Yuri Gagarin’s first spaceflight, but the first time a crew member stepped out from their spacecraft’s relative protection and immersed themselves in the cold, hostile emptiness of the vacuum.
On March 18, 1965, 30-year-old Russian cosmonaut Alexey Leonov completed a 12-minute spacewalk. This feat, and that of Gagarin and Sputnik before, was just one of the many achievements of the Soviet space program in the early years of the space race.
Leonov and others who followed him wore specially designed space suits, were tethered and later had helpful gadgets to move them around. Without the tether astronauts would have floated into empty space, with nothing to slow or change direction in frictionless space, with no rescue possible and only an inevitable death as their oxygen supply ran out. If this sounds daunting, imagine being the first ever to have faced this.
Only recently have we started to develop robotic equipment versatile and sensitive enough to carry out the complex tasks requiring fine motor skills taken for granted in any lab on Earth. Before then, astronauts had to walk in space and use these tools to repair satellites – such as the Hubble space telescope, which has given us the incredible science and images for the past 25 years. Spacewalks helped ensure we could walk on the moon, take samples and set up experiments.
Building the knowledge required to walk in space, and the robotic equipment to later help astronauts, also led toward the establishing of the US Skylab and Russian Mir orbital space labs, and their successor in the International Space Station (ISS).
The Cassini mission that has investigated Saturn since 2004 has revealed much about the giant planet and its many moons. Perhaps most tantalizing is the discovery that the moon Enceladus is the source of strong geysers ejecting plumes of water and ice.
A new study of Cassini data published in Nature by Hsiang-Wen Hsu and colleagues reveals these plumes are laced with grains of sand. This indicates that hydrothermal activity may be at work in Enceladus’ sub-surface ocean, and propels this tiny moon into the extremely exclusive club of locations that could harbor life.
The club’s only current member is Earth, of course – although it’s very possible that Europa, one of Jupiter’s moons, is, like Enceladus, also a candidate. What they have in common is that they host liquid oceans of salty water that exists in contact with a rocky, silicate seabed from which the oceans can absorb complex minerals and elements.
The NASA spacecraft Dawn has spent more than seven years traveling across the solar system to intercept the asteroid Vesta and the dwarf planet Ceres. Now in orbit around Ceres, the probe has returned the first images and data from these distant objects.
But inside Dawn itself is another first – the spacecraft is the first exploratory space mission to use an electrically-powered ion engine rather than conventional rockets.
Such ion engines will propel the next generation of spacecraft.
We all know and love the moon. We’re so assured that we only have one that we don’t even give it a specific name. It is the brightest object in the night sky, and amateur astronomers take great delight in mapping its craters and seas. To date, it is the only other heavenly body with human footprints.
What you might not know is that the moon is not the Earth’s only natural satellite. As recently as 1997, we discovered that another body, 3753 Cruithne, is what’s called a quasi-orbital satellite of Earth. This simply means that Cruithne doesn’t loop around the Earth in a nice ellipse in the same way as the moon, or indeed the artificial satellites we loft into orbit. Instead, Cruithne scuttles around the inner solar system in what’s called a “horseshoe” orbit.
Pluto is the largest object in the Kuiper belt, and NASA’s New Horizons spacecraft will arrive there on July 15.
These two events will make 2015 an exciting year for solar system exploration and discovery. But there is much more to this story than mere science. I expect 2015 will be the year when general consensus, built upon our new knowledge of these two objects, will return Pluto and add Ceres to our family of solar system planets.
The efforts of a very small clique of Pluto-haters within the International Astronomical Union (IAU) plutoed Pluto in 2006. Of the approximately 10,000 internationally registered members of the IAU in 2006, only 237 voted in favor of the resolution redefining Pluto as a “dwarf planet” while 157 voted against; the other 9,500 members were not present at the closing session of the IAU General Assembly in Prague at which the vote to demote Pluto was taken. Yet Pluto’s official planetary status was snatched away.
Ceres and Pluto are both spheroidal objects, like Mercury, Earth, Jupiter and Saturn. That’s part of the agreed upon definition of a planet. They both orbit a star, the Sun, like Venus, Mars, Uranus and Neptune. That’s also part of the widely accepted definition of a planet.
I have always been in awe of the night sky, trying to comprehend the vastness of space and the countless wonders it contains. But I have always felt a certain dissatisfaction with only being able to see it at a distance.
One day I imagine that humanity will be able to visit other planets in the solar system, and venture even further to other stars, but this has always seemed very far away. That’s the reason why I applied for the Mars One mission, aimed at starting a human colony on Mars – it seemed like a real opportunity to get closer to the rest of the night sky, to give me a chance to be a part of taking humanity into the stars.
Mars is, in a way, the perfect stepping stone into the rest of the universe. Despite its inhospitable conditions, it has a day-night cycle only 39 minutes longer than on Earth. Unlike the moon, it is resource-rich, and has a soil and atmosphere rich in water and nitrogen respectively. Mars does not suffer from the sweltering heat and toxic atmosphere found on Venus, closer to the sun from Earth, but still receives enough light from the sun to enable the generation of solar power.
I was seduced by infinity at an early age. Georg Cantor’s diagonality proof that some infinities are bigger than others mesmerized me, and his infinite hierarchy of infinities blew my mind. The assumption that something truly infinite exists in nature underlies every physics course I’ve ever taught at MIT—and, indeed, all of modern physics. But it’s an untested assumption, which begs the question: Is it actually true?
Last week, BICEP2 scientists — who in March announced evidence of cosmic inflation, a potentially Nobel-worthy find — threw handfuls of dust on the grave of their own results. The official paper [pdf], just published on the BICEP website, tells the story of how they mistook cosmic dust for “primordial gravitational waves,” and why everybody needs to calm down and stop trying to bury inflation, too.
Just 10-35 seconds after the Big Bang, cosmologists (or at least most of them) believe the universe expanded in hyperdrive — faster than it ever has since and faster than it ever will again. This ballooning, called inflation, smoothed everything out. It turned the cosmos into the roughly homogenous place we see today, and perhaps created other universes that add up to the sci-fi-sounding “multiverse.”
But it’s difficult to find direct evidence that inflation actually happened (after all, it was a long time ago). That’s where B-modes, which the BICEP2 team saw, come in.
The claim made headlines worldwide, hailing one of the biggest scientific discoveries in decades. After 35 years of research, astronomers said in March, they had found evidence that the universe underwent a brief but ultra-fast expansion when it was roughly a trillionth of a trillionth of a trillionth of a second old. The research team could see a Nobel Prize looming in the distance. So they popped bottles of bubbly in celebration and shared their excitement with the world.
But results confirmed today indicate that the fizz has long gone out of those findings. A second team of astronomers, which includes the initial BICEP2 team itself, used the European Space Agency’s Planck satellite to show that the twisting patterns did not come from the cosmic microwave background at all. They’re nothing but swirling patterns of dust.