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I'm really lucky to have almost no light pollution at night. A smartphone app that we enjoy is called Night Sky. You point your phone and it shows you the names of the stars you're looking at. It works in broad daylight too and, needless to say, if you have a tablet, you can see more easily.
The images were captured with an instrument built at the California Institute of Technology called the Cosmic Web Imager. The device was installed on the Hale 200-inch telescope at Palomar Observatory near San Diego, California. IGM is a network or web of thread-like formations of diffuse gases left over from the Big Bang that links all the galaxies in the universe together. Christopher Martin, professor of physics at Caltech, created and developed the device. Ive been thinking about the intergalactic medium since I was a graduate student, he said. Not only does it comprise most of the normal matter in the universe, it is also the medium in which galaxies form and grow. The first intergalactic filaments of IGM imaged by Martins team were within an area of space occupied by a quasar and something known as a Lyman alpha blob considered to be one of the largest objects in the universe which was found within a developing galaxy cluster.
Lyman alpha blob in emerging galaxy cluster SSA22 imaged with Caltechs Cosmic Web Imager. The arrows show the gas filaments of the IGM flowing into blob.
Martin and his colleagues observed one narrow filament that flowed into the quasar. The astronomers determined that it was about one million light-years long and might be powering the growth of the galaxy that contains the quasar. The team also found three filaments surrounding the Lyman alpha blob. Measurements indicated the diffuse gas from the filaments was pouring into the blob and affecting its dynamics. The scientists associated with the Cosmic Web Imager say the device has already spotted one possible spiral-galaxy, three times the size of our Milky Way galaxy, that is still developing.
Planet Outside Solar System Spins Itself Into 8-hour Days
For the first time, astronomers have been able to measure the rotational speed of an exoplanet. They found that a day on Beta Pictoris b, a young planet discovered about six years ago, is just eight hours long. A team of astronomers from Leiden University in the Netherlands used the European Southern Observatorys Very Large Telescope to make the measurement. The team found that the planet, which is more than 16 times larger and has 3,000 times the mass of Earth, orbits its sun at a speed of about 100,000 km per hour at its equator.
Artist rendering of Beta Pictoris b orbiting its star. The exoplanet is the first to have its rotation rate measured.
Compare that to Earth, which rotates at an equatorial velocity of 1,700 km per hour, resulting in 24-hour days. It is not known why some planets spin fast and others more slowly, says Remco de Kok, co-author of a paper outlining the discovery. But this first measurement of an exoplanets rotation shows that the trend seen in the Solar System, where the more massive planets spin faster, also holds true for exoplanets. This must be some universal consequence of the way planets form. Beta Pictoris b orbits Beta Pictoris, a star visible to the naked eye, which is about 63 light-years from Earth. The star and its planet are within the southern constellation of Pictor, which means the painters easel in Latin. Beta Pictoris b was also one of the first exoplanets to be directly imaged. Orbiting its star at a distance of about 1,196,782,968 km or 8 times the distance of the Earth from the Sun, its also the closest extrasolar planet to its star to be directly imaged.
Astronomers Capture 3D Images of Mysterious Intergalactic Matter Science World
I did a project in San Marcos once and had to specify low pressure sodium lamps for all my exterior parking standards because the site was in close proximity to Mt. Palomar.
I'm really lucky to have almost no light pollution at night. A smartphone app that we enjoy is called Night Sky. You point your phone and it shows you the names of the stars you're looking at. It works in broad daylight too and, needless to say, if you have a tablet, you can see more easily.
Writing in the journal Nature, researchers from the University of British Columbia say a Fast Radio Burst appears to originate from “a highly magnetized, gas-filled region of space.” FRBs, "bursts of energy from space that appear as a short flashes of radio waves to telescopes on Earth," last less than a second. "We now know that the energy from this particular burst passed through a dense magnetized field shortly after it formed," said Kiyoshi Masui, an astronomer with the University of British Columbia in Canada and lead author of the new findings.
This is an artist impression of a Fast Radio Burst reaching Earth. The colors represent the burst arriving at different radio wavelengths, with long wavelengths (red) arriving seconds after short wavelengths (blue).
There are only 16 cases of recorded FRBs, but researchers say there could be thousands a day. This particular one has been named FRB 110523 and is believed to have originated no more than 6 billion light-years away from Earth, placing it well outside our galaxy. After sifting through massive amounts of data collected through radio astronomy, researchers say FRB 110523’s burst showed a Faraday rotation, “a corkscrew-like twist radio waves acquire by passing through a powerful magnetic field.”
The data also revealed that the burst had passed through to different areas of ionized gas called screens. One of the screens appears to have been close, within a thousand light-years, to the source of the FRB, researchers said. "This significantly narrows down the source's environment and type of event that triggered the burst--and means the source of the pulse likely resides within a star-forming nebula or the remnant of a supernova," said Masui.
Scientists Zero In on Radio Burst Source
Astronomers have measured the age of 70,000 stars across the Milky Way and put the results into a galactic map. It confirms what was already suspected about our galaxy's growth: it started in the middle and grew outward. This can be seen in the abundance of old stars near the centre of the disc. Presented at the 227th meeting of the American Astronomical Society in Florida, it is the largest such map ever assembled. "We're characterising in really unprecedented detail how the galaxy is formed, via this snapshot of stellar ages across the disc," lead researcher Melissa Ness told the BBC.
Can I see some ID please? Until now it was difficult to measure a star's age without detailed observation
The tendrils of the map extend out from the Earth, beyond the centre of the galaxy in one direction, and out to the very far reaches of the disc in the other. "And we not only have these ages in the plane of the disc, but also moving up above the galactic plane," added Dr Ness, who works at the Max Planck Institute for Astronomy in Germany. To calculate the age of each star, she and her colleagues used data from two telescopes. Firstly, the Apogee project - part of the ground-based Sloan Digital Sky Survey - sampled many thousands of stars, 300 at a time, using a wide swathe of wavelengths.
These spectra help astronomers to work out the chemical composition of stars, but cannot determine their age directly. So the team started with a subset of stars that had also been observed from space by the Kepler satellite. This telescope stares at a few stars for a long period of time, and can establish their mass. "If we know the mass of these Kepler stars, we can determine their ages," Dr Ness explained. This enabled her team to build a model relating a star's mass and age to its colour spectrum, from the Apogee data. That model could then be deployed to calculate ages for all the remaining stars, based purely on their spectra.
One for the ages
Writing in the journal Nature, a research team says green pea galaxies, which were discovered in 2007, “were likely the reason that the universe heated up about 13 billion years ago.” Several hundred thousand years after the Big Bang, the universe was very hot and dense, which caused matter to become ionized. About 380,000 years later, the universe cooled enough for matter to neutralize, leading to the formation of gas clouds of hydrogen and helium. These grew and eventually collapsed into the first stars and galaxies. Then, the universe got hot again.
A Hubble Space Telescope picture of primitive galaxies.
The reheating is key, because it led to the reionization of hydrogen about 13 billion years ago, just a billion years after the Big Bang. Why this happened is debated, but astronomers have long believed early galaxies caused the reheating. The team used data from the Hubble Space Telescope’s ultraviolet spectrometer to examine five relatively nearby green pea galaxies that are emitting a large quantity of ionizing photons into the intergalactic medium, or the space between galaxies. These photons are believed to be the reason for the reionization of the universe.
One galaxy, J0925+1403, which is 3 billion light-years away, had a particularly intense ejection of ionizing photons. This, researchers said, could explain “cosmic reionization” "This galaxy appears to be an excellent local analog of the numerous dwarf galaxies thought to be responsible for the reionization of the early universe," said University of Virginia astronomer Trinh Thuan. "The finding is significant because it gives us a good place to look for probing the reionization phenomenon, which took place early in the formation of the universe that became the universe we have today."
More observations needed
Landmarks from the Eifel Tower in Paris to the Empire State Building in New York to the Sydney Opera House will shut off their lights from 8:30 to 9:30 p.m. local time on Saturday. Individuals and businesses are encouraged to do the same in order to bring attention to the effect greenhouse gases are having on the planet.
The event is not aimed at demonstrably reducing the amount of carbon dioxide released into the atmosphere – such an effort would require tens of millions of people to shut off lights for much longer than an hour. Instead, it's meant to make people more conscious of the energy they use and consume during the course of their everyday life, and think about the source of that energy. Often it comes from fossil fuel, the burning of which is believed to be the main driver of greenhouse gases that are causing global warming.
A view of the Eiffel Tower an instant with its lights switched off for the Earth Hour 2015 in Paris, France in 2015. People in 170 countries and 1,200 monuments' lights are to be switched off at exactly 8:30 p.m. local tie Saturday for one hour. Launched by the World Wildlife Fund, the event is meant to highlight the importance to fight global warming.
Earth Hour began as an event in Australia promoted by the World Wildlife Fund in 2007. A year later, landmarks around the world began participating and it became a global movement. It has grown to become one of the most visible environmental campaigns in the world. "Our tower lights are admired and beloved around the globe. The Empire State Building shines a light on major global issues and is part of the international conversation," Audrey Pass, chief marketing officer of Empire Realty Trust told the New York Daily News. The campaign urges people who participate to spend their hour dining by candlelight or playing games with flashlights.
Landmarks to go dark Saturday night for 'Earth hour'
More than 80 percent of humanity lives under skies saturated with artificial light, scientists have calculated. In the US and western Europe, that figure goes up to 99 percent of the population, most of whom cannot discern the Milky Way in the night sky. Artificial lighting has been shown to disturb the reproductive cycles of some animals and the migration of birds that navigate using the stars, and to disorient night-flying insects. For humans, circadian rhythms that regulate hormones and other bodily functions can also be thrown out of whack by too much light at night.
Even the most ardent critics of light pollution are not saying cities should go dark, or that lighting is not an essential element of urban life, but society needs to address a growing list of concerns, they said. “In general, it’s getting worse,” International Dark-Sky Association president Diana Umpierre said of light pollution in her home state of Florida, and things are moving in the wrong direction. “We are predicted to have 15 million more residents in the next 50 years” with all the extra lighting that entails, she said. By contrast, in Chad, the Central African Republic and Madagascar — not coincidentally among the poorest nations in the world — three-quarters of people have a clear view of the heavens.
Arguably, no one suffers more from light pollution than astronomers, whose telescopes are blinded by the glare of urban glow. In 1958 Flagstaff, Arizona — more than 2,100m above sea level — became the first sizeable city to curb night lighting, mainly to shield a major observatory. One of the biggest challenges in fighting light pollution is convincing people that “brightness” is not synonymous with “safety,” Umpierre said. “Sometimes it’s just the opposite,” she said, citing studies showing that people drive more carefully — and more slowly — on roads with less or no lighting at night. Over the past 15 years, biologists, doctors, non-governmental organizations and even UNESCO have joined the fight against light pollution by detailing negative impacts to health and well-being.
In 2012, the American Medical Association (AMA) concluded that exposure to “excessive” night light “can disrupt sleep and exacerbate sleep disorders” and it called for more research into possible links to cancer, obesity, diabetes and depression. Last year, the AMA raised another red flag, this time about LEDs. Local governments in wealthy nations are racing to replace existing streetlights with LEDs, which consume less energy and last longer. In the US, 10 percent of public lighting has already switched over to LED. That is good news for the fight against global warming, cutting down on fossil-fuel burning for electricity, but it might be bad news for health, the AMA said. “Some LED lights are harmful when used as street lighting,” AMA board member Maya Babu said.
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