Meet Miranda: a Moon with a View


via THE UNIVERSE — Meet Miranda: a Moon with a View Miranda doesn’t….

Miranda doesn’t seem like a particularly important moon. It is one of five main satellites orbiting Uranus, travelling along the innermost orbit. It is only 472km in diameter – the smallest of the five major moons. While its surface appears bright, it is in fact second to Ariel in brightness. But Miranda’s unassuming statistics hide a secret. As Voyager 2 passed by Uranus in 1986, it sent back images of an unexpectedly fascinating world.

Nicknamed the ‘Frankenstein moon’, Miranda’s surface merges together like mismatched patchwork. Smooth areas appear alongside heavily cratered ones, and gigantic cliffs give way to deep canyons. However, the most interesting features of this bizarre coalition are the three giant coronae. In this image, the coronae are the “chevron” figures enclosed by concentric lines. Each corona measures around 200km across, and is surrounded by parallel grooves and concentric ridges. They are shaped roughly like trapezoids, giving the impression that Miranda doesn’t quite fit together.

Scientists have proposed several different explanations for Miranda’s curious features. One reason could be that at some point in its history, Miranda was smashed apart in a violent collision, and then gravity caused the fragments to reassemble in a haphazard manner. As rocky material submerged into the newly reformed moon, it produced concentric creases, forming the coronae.
Another possibility suggests that the coronae are impact sites from large meteorites. Miranda is thought to comprise of roughly even amounts of silicate rock and water ice. As these meteorites collided with the moon, they partially melted the ice beneath the crust, causing water to make its way to the surface where it would then refreeze.

However, the most likely scenario to explain Miranda’s exotic features places Uranus squarely into the picture. Given Miranda’s small size, it would have cooled quickly after its formation. This particular structure doesn’t possess the radioactive materials like Earth has to keep its centre hot. Instead, through three-dimensional computer simulations, researchers have demonstrated how Uranus influenced the structure of the moon.

As a result of its gravitational pull, Uranus generated tidal forces, melting the moon from the inside out. In this model, Miranda once had a more oval-shaped orbit. As its proximity to Uranus shifted, the tidal effects constantly stretched and compressed Miranda, enough to generate a considerable amount of heat. This heat was transmitted to the icy mantle so that the crust receded, allowing new material to rise up in its place and form the coronae. As Miranda’s orbit gradually stabilized, the moon stopped producing heat and cooled down into its present form.

Miranda has proved to be a fairly complex world. While we have only seen the southern hemisphere, as Voyager 2 only imaged the one half, we have still been able to view one of the most diverse landscapes ever found on an extra-terrestrial object.

~ eKAT

IMAGE CREDIT:
NASA/JPL-Caltech
SOURCES:
Miranda: Overview.
Bizarre Shape of Uranus’ ‘Frankenstein’ Moon Explained.
Sparrow, Giles 2015, ‘The Solar System’, Astronomy in Minutes, Quercus Editions Ltd, London.

(Source: facebook.com)

The Solar Neutrino Problem


via THE UNIVERSE — The Solar Neutrino Problem As the sun converts….

As the sun converts hydrogen to helium within its core, there are always different particles released at each stage. These particles are essentially waste so they depart the sun, although at various rates.

During the first phase of fusion two Hydrogen atoms fuse together to make Deuterium, a heavier form of Hydrogen that contains a neutron. Usually Hydrogen contains only 1 proton and NO neutrons. According to our best solar models, the first neutrino produced during the fusion process comes from this step.

Neutrinos are electrically neutral particles with an extremely low mass. They interact with other particles so weakly that they travel through ordinary matter with extraordinary ease. Every second, huge numbers of neutrinos are emitted from the sun, carrying a very small fraction of the energy that is liberated from fusion reactions. They leave the sun and stream right through Earth. In fact, while you are reading this sentence, more than a billion neutrinos will pass through your head. The incredibly low interaction rate of the neutrino makes them difficult to study. I mean, how do we even know they are there??

Experiments to detect them have been running since 1970; the first was set deep in an abandoned gold mine in South Dakota. Being underground helped minimise possible false results by cutting out various other particles.

The neutrino detector consisted of a large tank containing over 600 tonnes of tetrachloroethene – a liquid used in dry cleaning that contains carbon and chlorine. As neutrinos flooded the tank, one would occasionally interact with a chlorine nucleus. Quite surprisingly, every time this interaction happened an argon nucleus was produced. At the end of an 80 day run the contents of the tank were emptied and the argon nuclei counted. What lay before them was an almighty task, as usually only 50 or so argon nuclei were found amongst the approximately 100000000000000000000000000000000 nuclei in the tank (that’s 10 with 31 zeros after it by the way).

The results of this experiment led to what is now known as the solar neutrino problem. The observed neutrinos implied a rate of production that was only one third of that expected. Since this initial experiment in the South Dakota mine, the deficit of solar neutrinos has been confirmed by other experiments that detect neutrinos in a variety of ways.

The answer turned out to be that there are actually three different types of solar neutrino: the electron neutrino, the muon neutrino and the tauon neutrino. Although only the electron neutrino is emitted by the sun, some of them can change type on their journey through space. The South Dakota mine experiment could only detect the electron neutrino type, and the experiments that followed could only detect one type of neutrino at a time. These results made sense as the experiments always detected only one third of the expected neutrinos.

In the late twentieth century solar astronomers finally cracked the issue when they set up an experiment in Canada that could detect all 3 types of neutrino. It used a spherical tank that held 1000 tonnes of “heavy” water surrounded by 9500 photosensitive cells that could detect tiny flashes of light from any particle interactions (the photo shows some technicians cleaning the cells inside such a tank). When they announced their results, it was confirmed that the theory from solar models regarding nuclear reactions, was in fact correct.

– DRR

Further reading
Image credit: Michael Richmond, licensed under a Creative Commons license

(Source: facebook.com)

 

Scientists might have discovered alien life on a comet – Salon.com


via Scientists might have discovered alien life on a comet – Salon.com.

MONDAY, JUL 6, 2015

The comet that a spacecraft landed on last year appears to be home to viral particles

JENNY KUTNER

Landing a spacecraft on a comet might be an even bigger deal than scientists believed as recently as last year, when the European Space Agency pulled off the magnificent feat in November. According to new reports, the comet in question might be home to alien lifeforms.

 philae 001

Philae, the spacecraft that landed on comet 67P/Churyumov-Gerasimenko, underwent a period of hibernation that ended in June, and has since indicated that there might be “an abundance of alien microbial life” on the comet’s surface,according to The Guardian:

Features of the comet, named 67P/Churyumov-Gerasimenko, such as its organic-rich black crust, are most likely explained by the presence of living organisms beneath an icy surface, the scientists have said.

Rosetta, the European spacecraft orbiting the comet, is also said to have picked up strange clusters of organic material that resemble viral particles. […]

The scientists have carried out computer simulations that suggest microbes could inhabit watery regions of the comet. Organisms containing anti-freeze salts could be active at temperatures as low as -40C, their research shows.

The comet has a black hydrocarbon crust overlaying ice, smooth icy “seas” and flat-bottomed craters containing lakes of re-frozen water overlain with organic debris.

[Astronomer and astrobiologist Chandra] Wickramasinghe said data coming from the comet seems to point to “micro-organisms being involved in the formation of the icy structures, the preponderance of aromatic hydrocarbons, and the very dark surface”.

Scientists also say the comet could provide a similar environment to the otherwise inhospitable areas on Earth occupied by “extremophile” microbes, though it’s unclear what that means for those “terrestrial” organisms.

 

Jenny Kutner

Jenny Kutner is an assistant editor at Salon, focusing on sex, gender and feminism. Follow @jennykutner or email jkutner@salon.com.

 

Pluto’s weird moons tango with gravity


via Pueo Eyes — starstuffblog: The Science Report by Stuart….

Pueo eyes.

starstuffblog:

The Science Report by Stuart Gary

I’ve just written a story for ABC Science about new data showing that the orbits of Pluto’s four smaller moons are thrown out of kilter by the gravitational tug-of-war between Pluto and its largest moon Charon.

The study, published in the journal Nature, provides new insights into how this chaotic system at the solar system’s outer rim formed.

Unlike most planetary systems which consist of a planet orbited by moons, Pluto and its largest moon Charon orbit each other around a common centre of gravity in a binary system.

This binary is in turn is orbited by four smaller moons – Nix, Hydra, Kerebos and Styx.

If you missed my radio report on the story and want to find out more, check out the online version at:
http://www.abc.net.au/science/articles/2015/06/04/4248036.htm

 

PLUTO YOU’RE GORGEOUS!


via CHRONOS & CHAOS – itsmangytime: homostook: hungry-for-change: ….

 

itsmangytime:

homostook:

hungry-for-change:

diedinpompeji:

PLUTO 2015

NASA

I AM SCREAMING OH MY GOODNESS

OH MY GOD DO YOU GUYS UNDERSTAND HOW AMAZING THIS IS

I HAVE BEEN READING ASTRONOMY BOOKS FOR YEARS AND EVERY TIME THERE’S JUST A PIXELLY BLUR FOR PLUTO

NOT ANYMORE. NEVER AGAIN.

If this is real OH MY GOD PLUTO YOU’RE GORGEOUS!

 

What is the Sun Made of?


via Δ S > 0 • the-actual-universe: What is the Sun Made of?….

the-actual-universe:

What is that big yellow ball made of? Most of us are taught that it is a giant sphere of gas or plasma that ‘burns’ from something called nuclear fusion and that it is mostly hydrogen. But what is the rest of it and how do we know?

We can look at the sun with instruments called spectrometers. These instruments can see specific kinds of light, also known as the electromagnetic spectrum, like red, green, or blue. Some instruments can detect beyond the colors we see into infrared, ultraviolet, radio, or X-rays.

When we look at the sun with these spectrometers we observe many of these slivers of light darkened or missing. Scientists have shown that each chemical element absorbs specific pieces of light. By working backwards we can determine what elements are on the surface of the sun (photosphere) and in its atmosphere as they will absorb these characteristic pieces of light and the darker the spots, the more of that element is present.

Observations of the sun have shown that it is 91.2% (71% by mass) hydrogen, 8.7% (27.1%) helium, and less than 0.1% (1.9%) everything else. The “everything else” consists of oxygen, carbon, nitrogen, silicon, magnesium, neon, iron, and sulfur in descending order with very small traces of dozens of others.

If we look closer at the spectrum we can observe different ions and isotopes of each element in the sun as the pieces of light that they absorb shift very slightly. The different isotopes can reveal clues as to what goes on deep in the core of the sun while the ions can provide information on the temperature of parts of the sun.
This is part of an ongoing series exploring our sun and how we observe it. Previously covered were “Colors” of the Sun and How Hot is the Sun? Next we will discuss how each element has a unique spectral ‘fingerprint’.

-LUX

Image Credit
Further Information:
Composition of the Sun
Sun Primer
Sun Fact Sheet

 

NASA says finding alien life almost certain within next two decades


via NASA says finding alien life almost certain within next two decades | Inhabitat – Sustainable Design Innovation, Eco Architecture, Green Building.

by Colin Payne, 04/12/15

nasa says life on other planets almost certain, alien life likely within 10-20 years, finding life on other planets, are we alone in the universe, life on mars, ganymede underwater ocean life

NASA recently gave a definitive answer to one of the biggest collective questions humanity has ever asked: are Earth’s inhabitants alone in the universe? NASA says the answer is “almost certainly no,” according to Phys.org. And while we could meet our alien neighbors within the next two decades, they may not take the form of what you’re used to seeing in science fiction.

nasa says life on other planets almost certain, alien life likely within 10-20 years, finding life on other planets, are we alone in the universe, life on mars, ganymede underwater ocean life

“I believe we are going to have strong indications of life beyond Earth in the next decade and definitive evidence in the next 10 to 20 years, NASA chief scientist for the National Aeronautics and Space Administration, Ellen Stofan said at a public panel in Washington earlier this week. “We know where to look, we know how to look, and in most cases we have the technology.

NASA interim director of heliophysics, Jeffery Newmark added that finding life beyond Earth is “definitely not an if, it’s a when.”

What do they expect to find? Don’t think Klingon or Ewok, think much smaller – microscopically smaller down to the microbe level. “We’re not talking about little green men,” Stofan noted. “We’re talking about little microbes.”

Related: NASA sending probe to Europa in search of ancient sub-glacial life

Mars is the main hot spot for NASA’s search for microbial life, as a study that analyzed the atmosphere above Mars’ polar caps suggests half of the planet’s northern hemisphere once had oceans a mile deep that contained water for as long as 1.2 billion years.

However, confirming life on the Red Planet might hinge on the ability to get boots on the ground in the form of field geologists and astrobiologists.

Another key location for life exploration is Jupiter’s moon Ganymede, which a recent study confirmed has a large liquid ocean underneath its icy surface. NASA believes the ocean may be a “habitable zone” where life could exist.

Via Phys.org

Images via Shutterstock and NASA, Flickr Creative Commons

For asteroid-capture mission, NASA picks a boulder | MNN – Mother Nature Network


via For asteroid-capture mission, NASA picks a boulder | MNN – Mother Nature Network.

The plan is to drag a boulder into lunar orbit, where astronauts will visit it beginning in 2025.

By: Mike Wall, Space.com Thu, Mar 26, 2015

Asteroids are known to harbor multiple boulders, so the mission will have a number of targets to choose from when it gets to the big space rock. (Photo: NASA)

 

NASA’s bold asteroid-capture mission will pluck a boulder off a big space rock rather than grab an entire near-Earth object, agency officials announced today (March 25).
NASA intends to drag the boulder to lunar orbit, where astronauts will visit it beginning in 2025. The space agency decided on the boulder snatch — “Option B,” as opposed to the whole-asteroid “Option A” — Tuesday (March 24) during the mission concept review of the asteroid-redirect effort, NASA Associate Administrator Robert Lightfoot told reporters during a teleconference today.
Option B will probably cost about $100 million more than Option A would have, but its advantages are worth the price-tag bump, Lightfoot said.
For example, large asteroids are known to harbor multiple boulders, so the mission will have a number of targets to choose from when it gets to the big space rock. Option A is riskier; the capture probe would likely have no recourse if its chosen asteroid proved too large to handle, or otherwise unsuitable.
Option B will also help develop more of the technologies humanity needs to extend its footprint beyond Earth, Lightfoot said.
“We are really trying to demonstrate capabilities that we think we’re going to need in taking humans further into space, and ultimately to Mars,” Lightfoot said. “That’s what we’re looking at.”
The asteroid plan
As currently envisioned, NASA’s Asteroid Redirect Mission (ARM) will launch a robotic probe in December 2020.
After about two years of spaceflight, the craft will rendezvous with a large near-Earth asteroid. NASA hasn’t decided yet which space rock to target, and the decision doesn’t have to be made until a year before launch, but the leading contender at the moment is the roughly 1,300-foot-wide (400 meters) 2008 EV5, agency officials said today.
The capture probe will assess the chosen asteroid’s boulders, grab one up to 13 feet (4 m) wide and then retreat to a “halo orbit” around the big space rock. The spacecraft will stay in this orbit for 215 to 400 days, long enough for the boulder-toting probe’s subtle gravitational tug to influence the orbit of the larger space rock.
This aspect of the mission should help researchers learn more about how to deflect asteroids that may pose a threat to Earth, Lightfoot said.
“Once we understand we’ve actually influenced the larger asteroid, then that gives us an idea — OK, how much more do we want to do that, or do we want to start heading back?” he said.
The capture probe will then turn around and head toward lunar orbit, where it should end up by late 2025. Two NASA astronauts will then journey out to meet the robotic spacecraft and the boulder, using the agency’s Orion capsule and Space Launch System megarocket, both of which are in development. This manned mission will likely last 24 or 25 days, Lightfoot said.
The cost of the robotic component of ARM — that is, the capture/redirect mission, without any astronaut visits —will be capped at $1.25 billion, not including the launch vehicle.
Getting the show on the road
Now that the mission-concept review is done and NASA has settled on Option B, the next big milestone for ARM is an “acquisition strategy meeting” in July.
“This is where we’ll decide how we’re going to procure all these systems,” Lightfoot said, citing the solar-electric propulsion system that will power the ARM capture probe as one prominent example. “We’ve got to get those pieces moving.”
He’s happy that ARM has put the design uncertainty in the rearview mirror.
“Let’s get on with it, so we can get this next key step in our journey to Mars moving on,” Lightfoot said.
Follow us @SpacedotcomFacebook or Google+This story was originally written for SPACE.com and was republished with permission here. Copyright 2015 SPACE.com, a Purch company. All rights reserved.

Supercomputer Simulation of Magnetic Field Loops on the Sun


via THE UNIVERSE — scienceisbeauty: Supercomputer Simulation of….

scienceisbeauty:

Via NASA Image of the Day

 

Why is Pluto no longer considered a Planet?


via blunt-science:Why is Pluto no longer considered a… | Scinerds.

blunt-science:

This is something that broke the heart of any kid who learned how to sing the names of all the planets at school, as it was suddenly made obsolete. Plus Pluto was arguably the cutest planet, but now, we all need to face facts and it seems people are unsure about the real reasons.

So, why is Pluto no longer considered a planet?

1) Peculiar orbital path and distance from the sun: Pluto has a path around the sun that is unlike all the other planets. It is at 17 degrees to the usual orbital plane and is much larger and erratic; sometimes even crossing the orbit of Neptune. It is 5.8 billion kilometres from the Sun, which to put in perspective is around 40 times further than the Earth is from the Sun. Even at it’s closest point it is still billions of kilometres away.

2) It could be in a binary system with Cheron: Although the moon and the Earth sometimes display binary traits; Pluto’s moon Cheron is extremely large comparatively. This results in a skewing of Cheron’s orbit around Pluto, making them both orbit each other simultaneously, as oppose to one orbiting the other.

3) It has not cleared it’s path: Pluto intersects with Neptune’s orbit, whilst also orbiting near objects smaller and even bigger than it. A planet should have strong enough gravity to clear it’s path and should be by far the biggest thing in its area. Putting this into perspective, Earth is 1.7 million times the mass of anything in its neighbourhood, whilst Pluto is only 0.07 times the mass in its neighbourhood.

Why all this rules Pluto out of the planet family?

As Planets are required to clear their paths, they don’t tend to cross each others orbits as their massive gravity’s don’t permit this. Not only that, Pluto’s orbit is so large that it drifts into the Kuiper belt. Inside the Kuiper belt has been dwarf planets even bigger than Pluto; such as Eris. This originally prompted the discussion on what a planet is. Due to the peculiar and erratic orbit, it appears that the Sun’s massive gravity attracted Pluto once upon a time whilst it was travelling past, although didn’t create an orbit as stable as the other planets.

Although we love and miss Pluto, It really should not have been considered a planet in the first place. It seems that it was originally a planet purely because we knew such a tiny amount about our solar system so far away and it was the biggest thing we knew out there. Once we found other space objects similar to Pluto, a definition was required.

Don’t be sad though, Pluto’s consolation prize is that space objects similar to it (such as dwarf planets) are now called “Plutoids”. How sweet.

(Via Youtube 1,2, NASA, HowStuffWorks, Scishow)

(via andromeda1023)