Uranus, photographed by the Hubble Space Telescope through various filters. Of note is what appears to be a cloud centre-right; Uranus looked almost completely featureless in Voyager’s pictures, but at least at some wavelengths, there is something going on in the atmosphere. The rings are also clearly visible in the last few frames (892nm methane filter). Assuming I made no interpretational blunders with HORIZONS data, Miranda is the small moon at the bottom of the frame, and Ariel is near the top.
Last week, this Tumblr went on a Hubble binge. This week: Keck! (Yes, in a desperate bid to keep the daily updates going, I’ve started using ground-based observations.) We start with Jupiter, seen from the Keck Observatory at Mauna Kea in Hawaii on 4 June 2010, at wavelengths of 1.95-2.3 microns (i.e., infrared). The gif covers about 30 minutes of real time. (Program ID C304N2L.)
Plants under the confocal microsope:Seeing is believing.
The last twenty years have seen a revolution in the application of optical techniques to the study of biological systems. Largely due to the development of highly specific fluorescent labelling methods, and optical techniques such as confocal laser scanning microscopy.
Different coloured fluorescent proteins are used routinely to decorate cells and subcellular structures in living tissues, and optical sectioning techniques allow visualisation of these labels.Meaning we can observe the different parts of any tissue and watch their movements.
1) An algae from the genus Cosmarium at 100x magnification, 2) the visual system of a pupal fruit fly at 1500x magnification showing the retina (brown), photoreceptors (blue), and brain (green),and 3) a bone cancer cell at 63x magnification showing protein filaments (purple), mitochondria (yellow), and DNA (blue).
The latest analysis of data from the Kepler planet-hunting spacecraft reveals that almost all stars have planets, and about 17 percent of stars have an Earth-sized planet in an orbit closer than Mercury. Since the Milky Way has about 100 billion stars, there are at least 17 billion Earth-sized worlds out there, according to Francois Fressin of the Harvard-Smithsonian Center for Astrophysics (CfA), who presented new findings today in a press conference at the American Astronomical Society meeting in Long Beach, California. Moreover, he said, almost all Sun-like stars have planetary systems.
The holy grail of planet-hunting is finding a twin of Earth – a planet of about the same size and in the habitable zone around similar star. The odds of finding such a planet is becoming more likely Fressin said, as the latest analysis shows that small planets are equally common around small and large stars.
While the list of Kepler planetary candidates contains majority of the knowledge we have about exoplanets, Fressin said the catalog is not yet complete, and the catalog is not pure. “There are false positives from events such as eclipsing binaries and other astrophysical configurations that can mimic planet signals,” Fressin said.
By doing a simulation of the Kepler survey and focusing on the false positives, they can only account for 9.5% of the huge number of Kepler candidates. The rest are bona-fide planets.
Each star in the Milky Way shines its light upon at least one companion planet, according to a new analysis that suddenly renders exoplanets commonplace, the rule rather than the exception. This means there are billions of worlds just in our corner of the cosmos. This is a major shift from just a few years ago, when many scientists thought planets were tricky to make, and therefore special things. Now we know they’re more common than stars themselves.
“Planets are like bunnies; you don’t just get one, you get a bunch,” said Seth Shostak, a senior astronomer at the SETI Institute who was not involved in this research. “So really, the number of planets in the Milky Way is probably like five or 10 times the number of stars. That’s something like a trillion planets.”
Of course there’s no way to know, at least not yet, how many of these worlds could be hospitable to forms of life as we know it. But the odds alone are tantalizing, Shostak said.
“It’s not unreasonable at this point to say there are literally billions of habitable worlds in our galaxy, probably as a lower limit,” he said. “Maybe they’re all sterile as an autoclave, but it doesn’t seem very likely, does it? That would make us very odd.”
Other astronomers maintain that we are odd indeed, and that increasing the known planet population does not increase the odds of finding intelligent life on any of them.
“The numbers are huge by any human standard, but we are still looking at only a tiny bit of our galaxy,” said John Gribbin, an astronomer and science writer who just published a book called “Alone in the Universe.” “[This research] does further our understanding of how things like planets form and how stars form, but there is a long way to go before we can say there is life on any of these planets, and further to go before we get to civilization.”
Image 2 |A Plethora of Planets:This artist’s impression shows how common planets are around the stars in the Milky Way. The planets, their orbits and their host stars are all vastly magnified compared to their real separations. A six-year search that surveyed millions of stars using a technique called microlensing concluded that every star has at least one planet orbiting around it. ESO/M. Kornmesser
Image 3 | A new analysis examined the frequencies of planets of different sizes based on findings from NASA’s Kepler spacecraft, correcting for both incompleteness and false positives. The results show that one in six stars has an Earth-sized planet in a tight orbit. Credit: F. Fressin (CfA)
Image 4 | This artist’s illustration represents the variety of planets being detected by NASA’s Kepler spacecraft. Credit: C. Pulliam & D. Aguilar (CfA)
First Transiting Planets in a Star Cluster Discovered
All stars begin their lives in groups. Most stars, including our Sun, are born in small, benign groups that quickly fall apart. Others form in huge, dense swarms that survive for billions of years as stellar clusters. Within such rich and dense clusters, stars jostle for room with thousands of neighbors while strong radiation and harsh stellar winds scour interstellar space, stripping planet-forming materials from nearby stars.
It would thus seem an unlikely place to find alien worlds. Yet 3,000 light-years from Earth, in the star cluster NGC 6811, astronomers have found two planets smaller than Neptune orbiting Sun-like stars. The discovery, published in the journal Nature, shows that planets can develop even in crowded clusters jam-packed with stars.
With Saturn’s rings in the foreground, Mimas is held in the centre of the frame, as Pandora moves past it.
There are a few things to like about this sequence. If you watch Mimas, you’ll see it rotating. It is in synchronous rotation, so that means we’re actually watching Mimas as it orbits (from this perspective) anti-clockwise; we can think of it moving off to the left, and the camera following it.
Pandora is orbiting in the same direction, but is closer to Saturn and orbits faster, “overtaking” Mimas as the camera follows the latter. But note that it seems to slow down at the end. That’s not because the camera’s taking photos more frequently, since Mimas’s rotation doesn’t slow down. What I think’s happening is that we’re not looking at these two moons when they’re diametrically opposite the camera relative to Saturn. Rather, Pandora is in a part of its orbit where it’s moving left and coming towards the camera. Mimas, with its larger orbit, will keep moving left for quite a while, but if the sequence had continued, Pandora would have looked like it was moving back to the right as its direction changes more towards the camera.
“There may be life there, but could it be technology-based like ours? Life on these worlds would be under water with no easy access to metals, to electricity, or fire for metallurgy. Nonetheless, these worlds will still be beautiful, blue planets circling an orange star — and maybe life’s inventiveness to get to a technology stage will surprise us.”
These two “Water World” planets orbit the star Kepler-62. This five-planet system has two worlds in the habitable zone — the distance from their star at which they receive enough light and warmth that liquid water could theoretically exist on their surfaces. Modeling by researchers at the Harvard-Smithsonian Center for Astrophysics (CfA) suggests that both planets are water worlds, their surfaces completely covered by a global ocean with no land in sight.
Kepler-62 is a type K star slightly smaller and cooler than our sun. The two water worlds, designated Kepler-62e and -62f, orbit the star every 122 and 267 days, respectively. They were found by NASA’s Kepler spacecraft, which detects planets that transit, or cross the face of, their host star. Measuring a transit tells astronomers the size of the planet relative to its star.
Kepler-62e is 60 percent larger than Earth, while Kepler-62f is about 40 percent larger, making both of them “super-Earths.” They are too small for their masses to be measured, but astronomers expect them to be composed of rock and water, without a significant gaseous envelope.
As the warmer of the two worlds, Kepler-62e would have a bit more clouds than Earth, according to computer models. More distant Kepler-62f would need the greenhouse effect from plenty of carbon dioxide to warm it enough to host an ocean. Otherwise, it might become an ice-covered snowball.
“Kepler-62e probably has a very cloudy sky and is warm and humid all the way to the polar regions. Kepler-62f would be cooler, but still potentially life-friendly,” said Harvard astronomer and co-author Dimitar Sasselov.
“The good news is — the two would exhibit distinctly different colors and make our search for signatures of life easier on such planets in the near future,” he added.
“Imagine looking through a telescope to see another world with life just a few million miles from your own. Or, having the capability to travel between them on a regular basis. I can’t think of a more powerful motivation to become a space-faring society,” said Sasselov.