#Star twinkles could help pin down planet sizes Twinkle twinkle little star and show us just how little you are.
Starlight captured by the Kepler space telescope has revealed that the amount a star flickers is tied to its size offering a better way to measure a wide variety of stars and their associated planets.
Kepler was designed to spot transits the periodic dips in a star's brightness indicating that a planet has passed in front of it.
Two years'worth of data still need inspecting including information about the thousands of stars in its field of view.
Figuring out the properties of stars is vital to planet surveys. When a planet transits a star the amount of light it blocks is used to calculate its size.
That can help to pinpoint whether it is rocky like Earth or gassy like Jupiter as long as the star's size is known.
Simply looking at a star's colour can reveal whether it is small and compact like our sun
or big and bloated like a red giant the type of star the sun will swell into in about 5 billion years.
But such estimates are crude with uncertainties of more than 90 per cent. Much more accurate size and mass measurements boasting uncertainties of just 2 per cent come from studying vibrations within the star called starquakes.
However this technique known as asteroseismology can be used only on bright stars because it requires teasing out subtle periodic variations in a star's light.
Fabienne Bastien of Vanderbilt University in Tennessee and colleagues used Kepler data to watch instead for flickers in starlight due to short-lived convection cells or granules on the star's surface.
These are bright regions where hot plasma wells up surrounded by darker boundaries where it cools
and falls back down. They began with a sample of about 500 stars whose size and mass were known already thanks to asteroseismology measurements made by Kepler.
They found a clear pattern: bigger more bloated stars flicker more. That's probably because each granule spans some two dozen times the width of the Earth in a giant star compared to just a fraction of the Earth's diameter in a compact star.
What we see over time is combined the effect of this network of bright granules flickering on and off says team member Keivan Stassun also of Vanderbilt.
The method provides stellar size and mass estimates with uncertainties of about 25 per cent a vast improvement over colour-based estimates says Stassun.
So far the flicker technique has been used to find the size and mass of about 1000 stars that do not have asteroseismology measurements
and it could be used to gauge the sizes of 50000 more stars already studied by Kepler Stassun says.
How will that affect the count of Earth-sized worlds? Kepler's principal investigator William Borucki expects the current pool of candidates to shrink.
He suspects we may have been underestimating the size of stars and therefore the planets that they host so many worlds currently deemed Earthlike may turn out to be too big.
or asteroseismology signals from sun-like stars says Jørgen Christensen-Dalsgaard of Aarhus University in Denmark who leads a consortium of researchers who analyse Kepler's starquake data.
#Solar system has shaped a tail like a four-leaf clover Lucky us! Our solar system has a tail reminiscent of a four-leaf clover according to new observations of the plasma bubble that shields the solar system from the rest of the galaxy.
The discovery should help us better understand how our star interacts with the Milky way including how harmful cosmic rays from interstellar space manage to sneak through the solar system's magnetic barrier.
The sun is currently zipping through one of the Milky way's spiral arms at a relative speed of about 23 kilometres per second ploughing through thin clouds of interstellar dust and gas.
At the same time a stream of particles blowing out from the sun the solar wind inflates a bubble of plasma around the solar system called the heliosphere Astronomers have assumed long that the sun's motion through the galaxy squashes
and spreads the heliosphere into a bullet shape with an extended tail at the back (see image).
We have seen similar tails in pictures of speeding stars elsewhere in the galaxy. But until now it has been hard to see for sure what our own sun's tail might look like.
Using the first three years of observations from NASA's Interstellar Boundary Explorer (IBEX) spacecraft astronomers were able to map this heliotail for the first time.
IBEX creates images of the solar system's borders by observing neutral atoms produced when charged particles from the solar wind collide with other charged particles in the outer heliosphere Some of these neutral atoms are bounced back towards us.
They are deflected not by magnetic fields as they travel so neutral atoms faithfully record the point of collision.
and paint a picture of the solar system using atoms instead of light Christian says. One surprise is that
The four lobes might be a reflection of solar activity at the time the particles left the sun says IBEX principal investigator David Mccomas. The particles took a few years to reach the tail
when the sun was minimally active. Around solar minimum you get slow solar wind around low to mid-latitudes from the sun
and high speed around high latitudes says Mccomas . But he expected this would create more of a solid horizontal band of slow particles across the tail not the odd lobes.
At solar maximum the bands of slow and fast particles streaming away from the sun break down so the tail may change its shape
when the sun's activity reaches its peak says Mccomas. Ultimately a better understanding of the tail
and where material from our solar system affects the rest of the galaxy and how the galaxy influences us.
Our own sun and the Earth and all of us are made up of atoms that came out of other stars'stellar winds long ago says Mccomas. There's a big recycling process that occurs
and the astrotails or heliotails are where the material coming out of stars or our sun leaves the region of the sun and gets mixed in with the rest of the stuff.
The heliotail could also be letting cosmic rays in says Brenda Dingus of Los alamos National Laboratory in New mexico who is not on the IBEX team.
But some manage to impinge on our solar system and previous observations have shown that they seem to come mostly from the tail's direction says Dingus.
It could be that the heliotail is acting as a funnel for cosmic rays allowing them to leak into the solar system where the sun's influence is weakest.
#Three habitable worlds found around the same star Aliens could be watching aliens watching aliens.
That's a realistic prospect now that three potentially habitable planets a record have been glimpsed orbiting the same star.
They found evidence for up to seven worlds including three rocky planets in the star's habitable zone where temperatures should suit life.
Located about 22 light years away Gliese 667c is itself part of a triple-star system making this one of the most crowded planetary neighbourhoods yet.
which can detect how a star is tugged back and forth by the gravity of an orbiting planet.
This is similar to the powerful streams of matter-antimatter observed outside pulsars and black holes. CERN physicist Niels Madsen notes though that the tabletop device has limitations.
and pulsars shoot through and interact with gases in the interstellar medium creating mini versions of these enigmatic astrophysical phenomena in the lab for the first time.
#Dust devils around stars may help planets grow A dusty tornado around a young star could help solve a lingering conundrum:
and astronomers have seen young stars ringed by dusty discs from which planets are assumed to form.
and start to drift towards the star. Eventually they either collide with each other and break apart or spiral in to their doom.
The farther you get from the star the smaller the clumps that can form before they start to drift inwards.
For a star like our sun a dusty clump in the same orbit as Earth can grow to about a metre wide.
Older observations had spotted a gap in the disc suggesting that the star has an orbiting body about 10 times the mass of Jupiter that is clearing a space.
and colleagues observed the star at three wavelengths: one sensitive to dust grains a millimetre across
But the millimetre-sized dust grains are concentrated in a large crescent-shaped structure on one side of the star a sign that a vortex may be holding the larger grains in place.
It is quite far from the star so it might be more of a comet factory says van der Marel.
We really hope that in the next coming years we're going to find similar dust traps around other stars where they are close enough to the star that they can form a planet she says.
#Antares rocket launch heats up private space race Watch out Spacex there's a new commercial rocket in town.
After a few delays due to weather and a technical glitch the Antares launch vehicle lifted off on its maiden flight on 21 april.
Antares built by spaceflight company Orbital Sciences of Dulles Virginia lifted off from the Mid-atlantic Regional Spaceport on Wallops Island Virginia at 22.00 GMT.
Antares was designed to deliver the company's Cygnus cargo craft to the ISS. For the test flight the rocket climbed high into a clear blue sky carrying a mock cargo ship with the same mass
Mars is going to pass behind the sun from Earth's perspective for the entire month of April blocking communications between the rover and mission control.
#8th-century tree rings hint at close-range space blast A blast of radiation that hit Earth circa AD 770 may have been caused not by a solar flare but by the energetic debris from the collision of two nearby neutron stars.
There is nothing similar anywhere else in around 3000 years of tree ring records leading Miyake to suggest a massive solar flare as the cause.
and there is no historical record of such an energetic solar flare. The aurora would have been seen up to tropical latitudes says Valeri Hambaryan of the University of Jena Germany.
Some researchers have suggested that an unknown supernova might be responsible for a red crucifix in the sky recorded in the Anglo-saxon Chronicle a history of Anglo-saxon life compiled by anonymous scribes.
and thought to be caused by the collision of two neutron stars black holes or white dwarfs. The pair suggest that the odd isotope levels in the trees
It should absorb virtually all wavelengths of light that reach Earth s surface from the sun but not much of the rest of the spectrum since that would increase the energy that is reradiated by the material
and has the additional benefits of absorbing sunlight from a wide range of angles and withstanding extremely high temperatures.
The sunlight s energy is converted first to heat which then causes the material to glow emitting light that can in turn be converted to an electric current.
In order to take maximum advantage of systems that concentrate sunlight using mirrors the material must be capable of surviving unscathed under very high temperatures Chou says.
And since the new material can absorb sunlight efficiently from a wide range of angles Chou says we don t need really solar trackers
In this paper the authors demonstrated in a system designed to withstand high temperatures the engineering of the optical properties of a potential solar thermophotovoltaic absorber to match the sun s spectrum.
but also light much as window blinds tilt to filter the sun. Researchers say the work could lead to waterproofing and anti-glare applications such as smart windows for buildings and cars.
or sunlight says Yangying Zhu a graduate student in MIT s Department of Mechanical engineering. So you could filter how much solar radiation you want coming in and also shed raindrops.
#Steam from the sun A new material structure developed at MIT generates steam by soaking up the sun. The structure a layer of graphite flakes
When sunlight hits the structure surface, it creates a hotspot in the graphite, drawing water up through the material pores,
if scaled up, the setup would likely not require complex, costly systems to highly concentrate sunlight.
who led the development of the structure. specially in remote areas where the sun is the only source of energy,
Cutting the optical concentration Today, solar-powered steam generation involves vast fields of mirrors or lenses that concentrate incoming sunlight, heating large volumes of liquid to high enough
when exposed to sunlight, vaporizing the surrounding water molecules as steam. But initiating this reaction requires very intense solar energy about 1, 000 times that of an average sunny day.
is that steam-generating applications can function with lower sunlight concentration and less-expensive tracking systems. his is a huge advantage in cost-reduction,
From sun to steam The approach itself is relatively simple: Since steam is generated at the surface of a liquid,
Ghasemi looked for a material that could both efficiently absorb sunlight and generate steam at a liquid surface.
As sunlight hits the structure, it creates a hotspot in the graphite layer, generating a pressure gradient that draws water up through the carbon foam.
and exposing it to a solar simulator a light source that simulates various intensities of solar radiation.
but the exact reason why the compound is so effective at blocking such a broad spectrum of sunlight has remained something of a mystery.
#Getting more electricity out of solar cells When sunlight shines on today solar cells, much of the incoming energy is given off as waste heat rather than electrical current.
In most photovoltaic (PV) materials, a photon (a packet of sunlight) delivers energy that excites a molecule,
which makes up almost half the sun electromagnetic radiation at the Earth surface. According to their estimates, applying their technology as an inexpensive coating on silicon solar cells could increase efficiency by as much as 25 percent.
and pilot their technology in outdoor solar systems. Unified Solar now becomes the finalist in the energy category in the MIT $100k Entrepreneurship Competition,
Sun exposure to solar panels produces about 0. 5 percent of wasted heat per Degree celsius increase.
The problem with solar power is that sometimes the sun doesn shine. Now a team at MIT and Harvard university has come up with an ingenious workaround a material that can absorb the sun heat
and store that energy in chemical form, ready to be released again on demand. This solution is no solar-energy panacea:
since it makes the sun energy, in the form of heat, storable and distributable, says Jeffrey Grossman, an associate professor of materials science and engineering,
Exposing them to sunlight causes them to absorb energy and jump from one configuration to the other,
taking in energy from the sun, storing it indefinitely, and then releasing it on demand.
while the sun isn out, being able to store heat for later use could be a big benefit.
and can withstand extreme temperatures, sun exposure, and heavy wear, says Doyle, the senior author of a paper describing the particles in the April 13 issue of Nature Materials.
for viewing faint objects that are close to brighter objects for example, a faint planet next to a bright star.
Plants typically make use of only about 10 percent of the sunlight available to them,
and it works much more reliably than lidar in bright sunlight when ambient light can yield misleading readings.
the Sun Jae Professor of Mechanical engineering at MIT. hat pretty much a description of what the ankle is.
First the cell absorbs sunlight which excites electrons in the active layer of the cell.
#Toward a low-cost'artificial leaf'that produces clean hydrogen fuel For years scientists have been pursuing artificial leaf technology a green approach to making hydrogen fuel that copies plants'ability to convert sunlight into a form of energy they can use.
Peidong Yang Bin Liu and colleagues note that harnessing sunlight to split water and harvest hydrogen is one of the most intriguing ways to achieve clean energy.
Producing hydrogen at low cost from water using the clean energy from the sun would make this form of energy
and exposed to sunlight produces hydrogen gas. The scientists say that the technique could allow their technology to be scaled up at low cost.
The researchers led by Professor Joel K. W. Yang at A*STAR (the Agency for Science Technology
To demonstrate how these nanopixels could enable high-resolution 3d color microprints the researchers designed a stereoscopic image containing stars on a 2d sheet by overlaying two slightly displaced views of the same image onto the same area.
Last spring Fan received a proof-of-concept grant from the Department of energy through the North Central Regional Sun Grant Center to determine
Sun Grant promotes collaboration among researchers from land-grant institutions government agencies and the private sector to develop
While they are not nearly as efficient as silicon-based solar cells in collecting sunlight and transforming it into electricity,
The new dye-sensitized solar cells were as much as 20 percent better at converting sunlight into power,
Over the years scientists have been very successful at making complex 3d shapes from DNA using diverse strategies said Wei Sun a postdoctoral scholar in the Wyss'Molecular Systems Lab
and functionally-relevant materials such as gold and silver Sun said. Just as any expanding material can be shaped inside a mold to take on a defined 3d form the Wyss team set out to grow inorganic particles within the confined hollow spaces of stiff DNA nanostructuresthe concept can be likened to the Japanese method of growing watermelons in glass cubes.
Professor Evans and his team have all of the membrane proteins required to construct a fully working mimic of the way plants capture sunlight.
A group of researchers from the Institute of Bioengineering and Nanotechnology (IBN) of A*STAR has taken the health benefits of green tea to the next level by using one of its ingredients to develop a drug delivery system
It should absorb virtually all wavelengths of light that reach Earth's surface from the sun but not much of the rest of the spectrum since that would increase the energy that is reradiated by the material
and has the additional benefits of absorbing sunlight from a wide range of angles and withstanding extremely high temperatures.
The sunlight's energy is converted first to heat which then causes the material to glow emitting light that can in turn be converted to an electric current.
In order to take maximum advantage of systems that concentrate sunlight using mirrors the material must be capable of surviving unscathed under very high temperatures Chou says.
And since the new material can absorb sunlight efficiently from a wide range of angles Chou says we don't need really solar trackers
In this paper the authors demonstrated in a system designed to withstand high temperatures the engineering of the optical properties of a potential solar thermophotovoltaic absorber to match the sun's spectrum.
Now researchers at A*STAR have used a process known as friction stir processing (see image) to produce an evenly distributed mix of nanosized aluminum oxide (Al2o3) particles in aluminum.
Guo J. F. Liu J. Sun C. N. Maleksaeedi S. Bi G. et al. Effects of nano-Al2o3 particle addition on grain structure evolution and mechanical behaviour of friction-stir-processed Al.
Researchers have known long that some single-celled organisms use a protein called bacteriorhodopsin (br) to absorb sunlight
If the researchers wanted to power their generators with sunlight, they'd need to improve on that.
acts as a large solar system that can be used to recharge portable electronics and lights for the upcoming night of camping."
calibrated to one Sun illumination (natural sunlight). The measurement itself is conceptually simple:""We're applying an oscillating voltage across the device
"We do this underneath the simulated sunlight. Mathematically, we're looking at the phase shifting of the current out relative to the voltage in."
"Co-authors are Xiaoping Hong, Jonghwan Kim, Su-Fei Shi, Yu Zhang, Chenhao Jin, Yinghui Sun, Sefaattin Tongay, Junqiao Wu and Yanfeng Zhang.
which degrade under exposure to sunlight and can also be difficult to align with imaging sensors.
It's a pitfall that could be important to understand in the development of long-lasting solar cells where sun could provide risky heat into the equation.
One example of a use for the material is in telescopes to increase the instruments'ability to see very faint stars.
For example it reduces stray-light improving the ability of sensitive telescopes to see the faintest stars
Collecting sunlight using these tiny colloidal quantum dots depends on two types of semiconductors: n-type which are rich in electrons;
and hold sunlight to drive the chemical reactions involved in water splitting. Semiconductors like silicon and gallium arsenide are excellent light absorberss is clear from their widespread use in solar panels.
While the overall efficiency of this cell is still low compared to other types about 9 percent of the energy of sunlight is converted to electricity the rate of improvement of this technology is one of the most rapid seen for a solar technology.
and thus boosting their overall efficiency in converting sunlight into electricity. Many approaches to creating low-cost large-area flexible and lightweight solar cells suffer from serious limitations such as short operating lifetimes
Just as a glass lens can be used to focus sunlight to a certain spot, these plasmonic nanostructures concentrate incoming light into hotspots on their surface,
The telescope's measurements will provide astronomers with clues to events early in the solar system's history according to the agency's description of the project.
Bill Joy-Chief Scientist and Cofounder-Sun Micro Systems sums it up best in this Wired article.
#Planet Without A Star Found â##We have seen never before an object free-floating in space that that looks like this.
It has all the characteristics of young planets found around other stars but it is drifting out there all aloneâ#stated team leader Michael Liu who is with the Institute for Astronomy at the University of Hawaii at Manoa. â
and is part of a star group named after Beta pictoris that also came together about 12 million years ago.
There is a planet in orbit around Beta pictoris itself but PSO J318. 5-22 has a lower mass
while looking for brown dwarfs or â##failed stars. â#PSO J318. 5-22â#s ultrared color stood apart from the other objects in the survey astronomers said.
The telescope was identified in the Pan-STARRS 1 wide-field survey telescope in Maui. Follow-up observations were performed with several other Hawaii-based telescopes including the NASA Infrared telescope Facility the Gemini North Telescope and the Canada-France-Hawaii Telescope.
A Bright Flash From The Sun At 8: 30 p m. Eastern time yesterday a solar flare peaked on the surface of the sun emitting an intense burst of radiation.
The sun is currently undergoing a solar maximum a peak of activity that occurs about every 11 years making solar flares like this more likely.
#How Technology Will Make Everyone A Great Photographer At the end of May the Chicago Sun-Times laid off all its staff photographers.
#As one might expect the Sun-Times decision has met with criticism. It s been called â##shortsightedâ
#and â##idiotic. â#There s even a Tumblr of head-to-head comparisons between the Sun-Times
And in theory it will give the Sun-Times even more reach by leveraging the cameras already in place at news events.#
The Sun-Times to benefit from that type of machine vision the software will need to process larger image batches from multiple sources.
In time those pieces may come together proving that the Sun-Times decision wasn t foolish it was just a bit before its time.#
#One In Five Sun-Like Stars Have Earthlike Planets Back in February a team at Harvard announced they had found a possible Earthlike planet just 13 lightyears away.
The#study detailed the prevalence of these planets orbiting red dwarf stars and found#that about 15 percent have Earth-size planets within habitable zones.
However if you're stargazing from your backyard with only your eyes to guide you you wouldn't be able to see these cooler smaller stars.#
#Red dwarfs#are one-third the size and one-thousandth as bright as the sun. But in this week's PNAS Online Early Edition a team of researchers from#University of California at#Berkeley released a study that looks at how common Earth-size planets
are around stars that are more like our sun. The study found that for stars that more closely resemble our sun about 22 percent
or about one in five stars have these Earth-size planets within the habitable zone. The habitable zone includes orbits where planets receive the same amount of stellar energy from a star as the Earth receives from the sun. Earth-size planets include those that are between one and two times the size of Earth.
Perhaps the most exciting prospect of the study is the finding that#the closest potential Earthlike planet is only 12 lightyears away.
-and K-type stars visible to the naked eye from Earth. These stars'surface temperatures range from just a bit hotter than the sun's 5778 Kelvin to as cool as 4100 Kelvin all of which are hotter than the M-class red dwarfs studied previously.
I do think that this work is a new chapter but it's not a new book Petigura tells Popular Science.
Indeed earlier this year Petigura published another paper that investigated the prevalence of planets as small as Earth but only those within the orbit of Mercury much closer to the star than Earth's orbit.
Out of those 42000 stars the team found 603 planets 10 of which fit the bill for orbit
So using custom-built software called TERRA Petigura corrected for the challenges associated with finding all of the planets orbiting stars in the Kepler field
I've been looking up at these stars quite a bit Petigura says. I was remembering questions I had when
and wondering how many of those stars have planets that are in some way like the Earth. And learning more about planets with similar positioning
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