Tag: Solar System

First Earth-Size Planet That Could Support Life Found

For the first time, scientists have discovered an Earth-size alien planet in the habitable zone of its host star, an “Earth cousin” that just might have liquid water and the right conditions for life.

The newfound planet, called Kepler-186f, was first spotted by NASA’s Kepler space telescope and circles a dim red dwarf star about 490 light-years from Earth.

While the host star is dimmer than Earth’s sun and the planet is slightly bigger than Earth, the positioning of the alien world coupled with its size suggests that Kepler-186f could have water on its surface, scientists say.




One of the things we’ve been looking for is maybe an Earth twin, which is an Earth-size planet in the habitable zone of a sunlike star,” Tom Barclay, Kepler scientist and co-author of the new exoplanet research said.

This [Kepler-186f] is an Earth-size planet in the habitable zone of a cooler star. So, while it’s not an Earth twin, it is perhaps an Earth cousin. It has similar characteristics, but a different parent.

Scientists think that Kepler-186f — the outermost of five planets found to be orbiting the star Kepler-186 orbits at a distance of 32.5 million miles, theoretically within the habitable zone for a red dwarf.

Earth orbits the sun from an average distance of about 93 million miles, but the sun is larger and brighter than the Kepler-186 star, meaning that the sun’s habitable zone begins farther out from the star by comparison to Kepler-186.

Other planets of various sizes have been found in the habitable zones of their stars.

However, Kepler-186f is the first alien planet this close to Earth in size found orbiting in that potentially life-supporting area of an extrasolar system, according to exoplanet scientists.

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Pass it on: New Scientist

 

New Horizons Discovers Pluto Has Blue Skies and Frozen Water

The first crewed mission to Pluto is going to be a master class in homesickness. After traveling 4.7 billion miles to the icy rock, those future pioneers breathing bottled air, bundled in awkward space clothes, buoyant in low gravity will have little to remind them of home.

But upon landing, they might just ease their pangs of longing by gazing up into the dwarf planet’s sky—which, scientists now know, is blue just like Earth’s.

NASA broke the news today by sharing the above photo of Pluto’s cerulean halo, taken in July by the New Horizons spacecraft.

Like Earth’s heavenly hue, Pluto’s blue sky is caused by tiny, sunlight-scattering particles in the atmosphere. Those particles probably begin as molecular nitrogen and other trace gases.




The sun’s ultraviolet rays break down and ionize these molecules, which then combine into larger (though still microscopic) particles.

The particles aren’t blue themselves; they’re reddish to grey, and are heavy enough that they eventually fall back down to the dwarf planet’s surface.

But wait! There’s more! See those conveniently-colored blue blobs on the above close-up? Those are frozen water, confirmed by combining spectral infrared and visible light data taken by two of New Horizons’ imagers.

What’s compelling to scientists (besides the fact that water exists) is why it appears where it does: on rocky outcrops near craters, and between mountains.

Another mystery is the water’s hue, which appears bright red in color imagery.

The New Horizons team thinks this indicates some sort of relationship between the surface ice and those atmospheric particles responsible for Pluto’s blue sky.

Maybe I’m biased, but those pretty skies and chunks of water make Pluto seem like a pretty good setting for Hollywood’s next lost-in-space blockbuster.

Damon, you up for getting stranded on yet another world?

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Pass it on: Popular Science

Neptune’s Moon: Triton

We don’t know with what beverage William Lassell may have celebrated his discovery of Neptune’s moon, Triton, but beer made it possible.

Lassell was one of 19th century England’s grand amateur astronomers, using the fortune he made in the brewery business to finance his telescopes.

He spotted Triton on 10 October 1846 — just 17 days after a Berlin observatory discovered Neptune.

Curiously, a week before he found the satellite, Lassell thought he saw a ring around the planet. That turned out to be a distortion caused by his telescope.

But when NASA’s Voyager 2 visited Neptune in 1989, it revealed that the gas giant does have rings, though they’re far too faint for Lassell to have seen them.

Since Neptune was named for the Roman god of the sea, its moons were named for various lesser sea gods and nymphs in Greek mythology.




Triton (not to be confused with Saturn’s moon, Titan), is far and away the largest of Neptune’s satellites. Dutch-American astronomer Gerard Kuiper (for whom the Kuiper Belt was named) found Neptune’s third-largest moon, Nereid, in 1949.

He missed Proteus, the second-largest, because it’s too dark and too close to Neptune for telescopes of that era.

Proteus is a slightly non-spherical moon, and it is thought to be right at the limit of how massive an object can be before its gravity pulls it into a sphere.

Proteus and five other moons had to wait for Voyager 2 to make themselves known. All six are among the darker objects found in the solar system.

Astronomers using improved ground-based telescopes found more satellites in 2002 and 2003, bringing the known total to 13.

Voyager 2 revealed fascinating details about Triton. Part of its surface resembles the rind of a cantaloupe.

Ice volcanoes spout what is probably a mixture of liquid nitrogen, methane and dust, which instantly freezes and then snows back down to the surface.

One Voyager 2 image shows a frosty plume shooting 8 km (5 miles) into the sky and drifting 140 km (87 miles) downwind.

Triton’s icy surface reflects so much of what little sunlight reaches it that the moon is one of the coldest objects in the solar system, about -400 degrees Fahrenheit (-240 degrees Celsius).

Triton is the only large moon in the solar system that circles its planet in a direction opposite to the planet’s rotation (a retrograde orbit), which suggests that it may once have been an independent object that Neptune captured.

The disruptive effect this would have had on other satellites could help to explain why Nereid has the most eccentric orbit of any known moon it’s almost seven times as far from Neptune at one end of its orbit as at the other end.

Neptune’s gravity acts as a drag on the counter-orbiting Triton, slowing it down and making it drop closer and closer to the planet.

Millions of years from now, Triton will come close enough for gravitational forces to break it apart possibly forming a ring around Neptune bright enough for Lassell to have seen with his telescope.

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Pass it on: New Scientist

Jupiter’s Strange Glowing Auroras Have A Mysterious Power Source

For the first time ever, NASA’s Juno spacecraft has spotted electrons being fired down into Jupiter’s atmosphere at up to 400,000 volts.

That’s an enormous amount of energy that gives rise to the planet’s glowing auroras. These incredibly high voltages, however, are only spotted occasionally and that’s raising questions about what exactly is behind some of the planet’s most vivid glows at the poles.

The discovery, detailed in a study published today in Nature, was made possible by the instruments on board Juno, which has been orbiting Jupiter for a little over a year, passing by the poles closer than any other spacecraft has before.

It confirms, in part, what astronomers expected, but it also shows that Jupiter’s auroras behave differently than auroras on Earth through processes that we don’t fully understand yet.

Auroras, on both Earth and Jupiter, are formed when charged particles like electrons spiral down a planet’s magnetic field lines, entering the atmosphere and creating a glow.




On Earth, the most intense auroras are caused by solar storms, which occur when high-energy particles ejected from the Sun rain down on our planet.

When these particles enter the atmosphere, they interact with gases and make the sky glow red, green, and blue at the poles.

On Jupiter, auroras are formed by particles ejected mostly from the Io, the planet’s moon. Io’s volcanoes spew huge amounts of sulfur and oxygen into space, loading Jupiter’s magnetic field with particles.

On both planets, electrons are accelerated along the magnetic field lines by electric currents — similar to the electric current that goes through the socket when you plug in your phone charger.

On Earth, the solar wind is the power source, firing electrons at up to 30,000 volts.

On Jupiter, it’s the planet’s superfast rotation that acts as a gigantic electric generator, so astronomers expected electrons to be fired by very high voltages on Jupiter as well.

But they had never observed this before, so Juno gave astronomers that opportunity for the first time.

The spacecraft is in an extremely elliptical orbit around Jupiter, passing very close to the poles every 53 days. To study Jupiter’s auroras, the probe was equipped with several instruments, including the Juno Energetic Particle Detector Instrument (JEDI).

The probe is traveling at about 30 miles per second over the poles, so the measurements have to happen in a matter of seconds, says study co-author Barry Mauk, lead for JEDI and a scientist at the Johns Hopkins University Applied Physics Laboratory, which made the instrument.

That was a very substantial challenge,” Mauk said. “We’re very proud of the fact that we were able to pull that off.”

On its first flyby over the auroras, however, Juno didn’t detect the high voltages astronomers expected. “We were very surprised,” Mauk says.

Then, in following flybys, the spacecraft finally detected the signature of electrons being fired down the atmosphere all at about the same energy — as high as 400,000 volts.

The curious thing, though, is that these high voltages aren’t always there, Mauk says. They’re only spotted occasionally.

And sometimes, Juno is spotting electrons being fired down the atmosphere with all different energies, in a seemingly random way.

What’s causing this random acceleration of electrons at different energies which create very bright auroras is a mystery, Mauk says.

The probe is going to keep flying by Jupiter’s poles, and every time it does so, it collects data. “Every time we have an encounter, we see different things,” Mauk says.

So Mauk is hoping that the next observations will help astronomers answer the questions of why the auroras are so variable, and why they are sometimes strong and sometimes weak.

The goal is not to only understand the physical processes behind auroras on the Solar System’s largest planet.

Other objects around the Universe like pulsars, exoplanets, and white dwarfs also have magnetic fields, and they also accelerate particles in a way that can resemble Jupiter’s.

But Jupiter is in our backyard, so it’s actually accessible. “Jupiter is not only interested in its own right, but it also tells us a great deal about similar astrophysical bodies that we can’t reach with spacecraft,” says Nichols.

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Pass it on: Popular Science

Astronomers Race To Study A Mystery Object From Outside Our Solar System

For the first time that we know, an interstellar visitor has zoomed through our solar system.

The small space rock, tentatively called A/2017 U1, is about a quarter of a mile long and astronomers across the world are racing to study it before it departs just as quickly as it arrived.

We’ve never seen anything like this before,” said Rob Weryk, an astronomer at the University of Hawaii Institute for Astronomy.

On Oct. 19, Dr. Weryk was reviewing images captured by the university’s Pan-STARRS 1 telescope on the island of Maui when he came across the object.

At first he thought it was a type of space rock known as a near earth object, but he realized its motion did not make sense. It was much faster than any asteroid or comet he had seen before.

He quickly realized that it was not of this solar system. “It’s moving so fast that the Sun can’t capture it into an orbit,” Dr. Weryk said.




After contacting a colleague at the European Space Agency to discuss the find, he submitted it to the Minor Planet Center, which tracks objects in the solar system, to share with other astronomers.

I was not expecting to see anything like this during my career, even though we knew it was possible and that these objects exist,” said Davide Farnocchia, a navigational engineer with NASA’s Center for Near-Earth Object Studies at the Jet Propulsion Laboratory in Pasadena, Calif.

Astronomers had predicted such an occurrence, but this is the first time that it has been recorded. For the past few days Dr. Farnocchia has been calculating the strange object’s path.

It was obvious that the object has a hyperbolic orbit,” he said, meaning that its trajectory is open-ended rather than elliptical like the objects in our solar system.

That shows that it came from outside the solar system and will leave the solar system.

The object came closest to the Sun on Sept. 9, at a distance of about 23 million miles. With a boost from the star’s gravity, it zoomed by at about 55 miles per second with respect to the Sun, Dr. Farnocchia said.

Then on Oct. 14 the object came within about 15 million miles of Earth, zipping by at about 37 miles per second, with respect to the Earth.

That’s more than three times as much velocity as the escape trajectory for the New Horizons spacecraft, which completed a flyby of Pluto in 2015, he said.

Now it’s moving away at about 25 miles per second, he said, and will exit the solar system at about 16 miles per second.

That is faster than the current velocity of the Voyager 1 spacecraft, which became the first spacecraft from Earth to enter interstellar space in August 2012.

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The Solar System May Be Hosting A Visitor From The Stars

Yesterday, the Minor Planet Center has announced the discovery of a new comet, C/2017 U1, by the PanSTARRS survey.

It is quite faint and we would not talk about it, but it has something very unique. It is the first comet which, so far, likely comes from outside the Solar System.

“So far”, as this statement is based on a few tens of observations. Tenagra Observatories, now partner of the Virtual Telescope Project, observed it while it was waiting for confirmation.

On the discovery circular, Gareth V. Williams, Associate Director of the Minor Planet center, wrote: “Further observations of this object are very much desired.




Unless there are serious problems with much of the astrometry listed below, strongly hyperbolic orbits are the only viable solutions.

Although it is probably not too sensible to compute meaningful original and future barycentric orbits, given the very short arc of observations, the orbit below has e ~ 1.2 for both values.

If further observations confirm the unusual nature of this orbit, this object may be the first clear case of an interstellar comet”. All this sounds quite exciting.

Its orbit is hyperbolic, so it is not a closed one.

Bill Gray, on the Minor Planet Mailing List (MPML), mentioned that, assuming the available data, this comet should arrive from the Vega direction, but a connection with a given star is still not available.

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Pass it on: New Scientist

Astronomers May Have Found The First Exomoon

When the first exoplanet—or planet orbiting another star—was discovered in 1992, it was a very big deal.

Today, we’ve discovered thousands of exoplanets and it takes a particularly noteworthy one to grab our attention.

We’ve spotted big exoplanets, small exoplanets, and everything in between.

Now scientists are moving on to the next big thing: Exomoons.




Researchers examining old data from the Kepler Space Telescope have spotted what they believe is the first-ever moon beyond our solar system to be found, and they’re planning to use the Hubble Space Telescope to confirm it.

As you might have guessed, the exomoon is an enormous one. The planet in question is Jupiter-sized, and the moon if it indeed exists is around the same size as Neptune.

The Kepler telescope observed the planet and its moon passing in front of their star, which caused the star’s brightness to dip slightly.

This exoplanet-exomoon pair is a strange one, and looks nothing like anything in our own solar system. The researchers believe that the larger, Jupiter-sized planet captured the smaller one and turned it from planet into moon.

Unfortunately, the observations from Kepler aren’t clear enough for the scientists to say definitively that the moon exists. That’s why they need to use Hubble to take a second look.

If Hubble confirms the moon’s existence, it will be the first exomoon ever found. With the many highly sensitive telescopes scheduled to be completed in the next few years, more exomoon discoveries are almost certain.

We’ll probably find a few really big moons over the next few years, and as our telescopes get better we might start finding moons that look like our own.

Pretty soon, exomoons will be old news too, so enjoy this discovery while it’s still fresh.

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According To Stephen Hawking, We Have Less Than 100 Years To Save The Human Race

The human race is entering the most dangerous 100 years in its history and faces a looming existential battle, Stephen Hawking has warned.

The theoretical physicist identified artificial intelligence (AI), nuclear war and genetically-engineered viruses as just some of the man-made problems that pose an imminent threat to humanity.

And the 74-year-old said that as we rapidly advance in these fields, there will be “new ways things can go wrong”.

We are at a point in history where we are “trapped” by our own advances, with humanity increasingly at risk from man-made threats but without technology sophisticated enough to escape from Earth in the event of a cataclysm.




He warned: “Although the chance of a disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next thousand or ten thousand years.

By that time we should have spread out into space, and to other stars, so a disaster on Earth would not mean the end of the human race.

However, we will not establish self-sustaining colonies in space for at least the next hundred years, so we have to be very careful in this period.

He added that humans do have a knack of “saving the day” just in time, and urged fellow scientists to continue trying to make advances in their respective fields.

Prof Hawking said: “We are not going to stop making progress, or reverse it, so we have to recognise the dangers and control them. I’m an optimist, and I believe we can.

It’s important to ensure that these changes are heading in the right directions. In a democratic society, this means that everyone needs to have a basic understanding of science to make informed decisions about the future.

So communicate plainly what you are trying to do in science, and who knows, you might even end up understanding it yourself.

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A Ring Has Been Found Around Haumea, A World More Than 2 Billion Kilometers Beyond Pluto

A ring system has been found around a dwarf planet for the first time — the distant, potato-shaped Haumea, which lies beyond Neptune.

Haumea, first discovered in 2004, is one of five dwarf planets: large objects like Pluto, mostly in the outer solar system, which are not quite significant enough for planetary status.

It is known for its peculiar and rapid rotation, spinning end-over-end once every four hours.

But the discovery of Haumea’s ring, reported today in the journal Nature, is another surprise for scientists.

This is the first time a ring around a dwarf planet has been discovered, so it is a really very peculiar, unexpected and weird finding,” said the paper’s co-author, Dr Pablo Santos-Sanz from the Instituto de Astrofísica de Andalucía.




The ring appears to be dense and dark, blocking out about half of the light that passes through it to Earth. It’s 70 kilometres wide and lies about 1,000 kilometres away from Haumea’s surface.

Associate Professor Jonti Horner from the University of Southern Queensland, commenting on the discovery, said rings may be more common than we thought.

Ring systems exist around the giant planets in our solar system: Jupiter, Saturn, Uranus and Neptune.

But the presence of a ring around Haumea, coupled with the recent discovery of rings around the “centaurs” Chiron and Chariklo even smaller bodies that orbit the Sun in the vicinity of the gas giants suggests ring systems could be found in a variety of environments, Dr Horner said.

If we’re finding them round [these] unusual objects, maybe they’re everywhere,” he said.

Until now, little was known about Haumea apart from its odd shape and spin.

To study the mysterious dwarf world in detail, Dr Santos-Sanz and his colleagues took advantage of its passing in front of a distant star.

The next step is explaining how that ring can form around such a peculiar body, and why the ring spins three times slower than the dwarf planet itself.

When we have more knowledge about all these open points we will be able to answer the question about where these ring systems can arise in the solar system,” Dr Santos-Sanz said.

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Tiny Nano-Flares May Solve The Sun Mystery

Small “nanoflares” erupting from the sun might be the key to unlocking a cosmic mystery, according to a new study.

Scientists have found that the sun’s outer atmosphere, or corona, can reach temperatures 1,000 times higher than those at the surface of the star, but solar physicists previously had no explanation for why this temperature discrepancy is so great.

Now, researchers think the relatively tiny flares may be the “smoking gun” that explains this mysterious cosmic occurrence.

The new study provides the first direct proof that nanoflares keep the sun’s corona at a temperature of millions of degrees, far hotter than the sun’s visible surface, which is about 6,000 degrees Kelvin (10,000 degrees Fahrenheit).

The nanoflare model has been around for a while,” said Jeffrey Brosius, a solar physicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland “With better instrumentation, we were hoping to find the evidence that was predicted by the model.

Nanoflares happen because of huge magnetic fields located throughout the sun’s corona.

These loops are anchored in the photosphere, the sun’s visible surface, but move around due to turbulence in the photosphere. Sometimes the field lines cross, and they become twisted and tangled.




When this happens in the presence of plasma, current sheets form, and the “stress” builds until the magnetic field “breaks,” releasing lots of energy very quickly.

This kind of crossing of magnetic fields can happen thousands of times a second over the whole solar surface, and this transfers energy to the plasma in the corona. That energy transfer could explain the corona’s extra heat.

Earlier evidence for this, though, was indirect. While other models didn’t fit observations, the model based on nanoflares was still missing a piece of the puzzle.

That missing evidence came from the Extreme Ultraviolet Normal Incidence Spectrograph mission, which picked up light emitted by a special kind of ionized iron, called Fe XIX.

The EUNIS instruments also spotted another form of ionized iron, Fe XII, which occurs at a temperature of 1.6 million degrees Kelvin, or about 2.9 million degrees Fahrenheit.

The ratio of the two ions showed that the corona is heated by short bursts, rather than a continuous input of energy, because that ratio – the brightness of Fe XIX relative to its cousin Fe XII – would only occur under certain physical conditions.

One of the predictions of the nanoflare model is there should be fairly widespread but faint emission of plasma at about 10 million Kelvin [18 million degrees Fahrenheit],” Brosius said.

James Klimchuk, a research astrophysicist at Goddard who was not involved in the study, said what’s new in the Brosius resultsis the detection of plasma hot enough to produce Fe XIX.

Before the EUNIS findings scientists thought it was very likely that nanoflares existed, the case for them wasn’t ironclad.

One reason for this doubt is that the emission from the ionized ironwas so hard to see because it was faint. Another is that the corona is “optically thin,” meaning that at some wavelengths, it’s basically translucent, like stained glass.

So the nanoflares, many occurring simultaneously and overlapping, tend to “wash out.”

The study appears in the August issue of the Astrophysical Journal.

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