Escape from Proxima b


A civilization in the habitable zone of a dwarf star like Proxima Centauri might find it hard to get into interstellar space with conventional rockets

Escape from Proxima b
Artist’s impression of the exoplanet Proxima Centauri b.

Almost all space missions launched so far by our civilization have been based on chemical propulsion. The fundamental limitation here is easy to understand: a rocket is pushed forward by ejecting burnt fuel gases backwards through its exhaust. The characteristic composition and temperature of the burnt fuel set the exhaust speed to a typical value of a few kilometers per second. Momentum conservation implies that the terminal speed of the rocket is given by this exhaust speed times the natural logarithm of the ratio between the initial and final mass of the rocket.

To exceed the exhaust speed by some large factor requires an initial fuel mass that exceeds the final payload mass by the exponential of this factor. Since the required fuel mass grows exponentially with terminal speed, it is not practical for chemical rockets to exceed a terminal speed that is more than an order of magnitude larger than the exhaust speed, namely a few tens of kilometers per second. Indeed, this has been the speed limit of all spacecraft launched so far by NASA or other space agencies.

By a fortunate coincidence, the escape speed from the surface of the Earth, 11 kilometers per second, and the escape speed from the location of the Earth around the sun, 42 kilometers per second, are close to the speed limit attainable by chemical propulsion. This miracle allowed our civilization to design missions, such as Voyager 1 and 2 or New Horizons, that could escape from the solar system into interstellar space. But is this fortune shared by other civilizations on habitable planets outside the solar system?

Life “as we know it” requires liquid water, which can exist on planets with a surface temperature and a mass similar to Earth. Surface heating is needed to avoid freezing of water into ice and an Earth-like gravity is needed to retain the planet’s atmosphere, which is also essential, since ice turns directly into gas in the absence of an external atmospheric pressure. Just next door to Mars, which has a tenth of an Earth mass and lost most its atmosphere long ago.

Since the surface temperature of a warm planet is dictated by the flux of stellar irradiation, the distance of the habitable zone around any arbitrary star scales roughly as the square root of the star’s luminosity. For low mass stars, the stellar luminosity scales roughly as the stellar mass to the third power. The escape speed scales as the square root of the stellar mass over the distance from the star.

Taken together, these considerations imply that the escape speed from the habitable zone of a star scales inversely with stellar mass to the power of one quarter. Paradoxically, the gravitational potential well is deeper in the habitable zone around lower mass stars. A civilization born near a dwarf star would need to launch rockets at a higher speed than we do in order to escape the gravitational pull of its star, even though the star is less massive than the Sun.

As it turns out, the lowest mass stars happen to be the most abundant of them all. It is therefore not surprising that the nearest star to the sun, Proxima Centauri, has 12 percent of the mass of the sun. This star also hosts a planet, Proxima b, in its habitable zone at a distance that is 20 times smaller than the Earth-Sun separation. The escape speed from the location of Proxima b to interstellar space is about 65 kilometers per second. Launching a rocket from rest at that location requires the fuel-to-payload weight ratio to be larger than a few billions in order for the rocket to escape the gravitational pull of Proxima Centauri.

In other words, freeing one gram’s worth of technological equipment from the position of Proxima b to interstellar space requires a chemical fuel tank that weighs millions of kilograms, similar to that used for liftoff of the space shuttle. Increasing the final payload weight to a kilogram, the scale of our smallest CubeSat, requires a thousand times more fuel than carried by the space shuttle.

This is bad news for technological civilizations in the habitable zone of dwarf stars.

Their space missions would barely be capable of escaping into interstellar space using chemical propulsion alone. Of course, the extraterrestrials (E.T.s) can take advantage, as we do, of gravitational assists by optimally designing the spacecraft trajectory around their host star and surrounding planets.

In particular, launching a rocket in the direction of motion of the planet would reduce the propulsion boost needed for interstellar escape down to the practical range of 30 kilometers per second. The E.T.s could also employ more advanced propulsion technologies, such as light sails or nuclear engines.

Nevertheless, this global perspective should make us feel fortunate that we live in the habitable zone of a rare star as bright as the sun. Not only that we have liquid water and a comfortable climate to maintain a good quality of life, but that we also inhabit a platform from which we can escape at ease into interstellar space. We should take advantage of this fortune to find real estate on extrasolar planets in anticipation of a future time when life on our own planet will become impossible.

This unfortunate fate will inevitably confront us in less than a billion years, when the sun will heat up enough to boil all water off the face of the Earth. With proper planning we could relocate to a new home by then. Some of the most desirable destinations would be systems of multiple planets around low mass stars, such as the nearby dwarf star TRAPPIST-1 which weighs 9 percent of a solar mass and hosts seven Earth-size planets.

Once we get to the habitable zone of TRAPPIST-1, however, there would be no rush to escape. Such stars burn hydrogen so slowly that they could keep us warm for ten trillion years, about a thousand times longer than the lifetime of the sun.

An Atmosphere Has Been Detected Around an Earth-Like Exoplanet for the First Time


Astronomers have detected an atmosphere around an Earth-like exoplanet called Gliese 1132b (GJ 1132b for short), which is located around 39 light-years away in the constellation Vela.

This is the first time atmosphere has ever been detected around a planet with a mass and radius so similar to Earth’s, and that makes it a hugely promising (and exciting) target for researchers searching for signs of extraterrestrial life.

 

“While this is not the detection of life on another planet, it’s an important step in the right direction: the detection of an atmosphere around the super-Earth GJ 1132b marks the first time that an atmosphere has been detected around an Earth-like planet other than Earth itself,” said lead researcher John Southworthfrom Keele University in the UK.

There’s still a lot to learn about GJ 1132b’s atmosphere, but early observations suggest it could be a “‘water world’ with an atmosphere of hot steam” – AKA, a pretty awesome place to go looking for life.

So far, we know that GJ 1132b has a mass about 1.6 times that of Earth’s, and has roughly 1.4 times its radius – which in terms of exoplanets makes it remarkably similar to our home planet.

But as with all exoplanet discoveries, the researchers are quick to remind the public that the observations to date still really don’t give us much insight into how similar GJ 1132b could be to Earth – or how habitable.

Some bad news upfront is it has an estimated surface temperature of 370 degrees Celsius (698 degrees Fahrenheit), which makes it unlikely that it could host life like us.

And let’s not forget that we’ve recently been burned by the detection of the TRAPPIST-1 ‘sister solar system’ and neighbouring Earth-like planet Proxima b, both of which are unlikely to be the friendly places for life we first thought they were.

 But none of those planets had ever gotten as far as having an atmosphere detected, so GJ 1132b is already doing pretty well in terms of a spot that could potentially host life.

Right now, the top strategy for astronomers in the search for life on another planet is to detect the chemical composition of that planet’s atmosphere, looking for certain chemical imbalances that could hint at the presence of living organisms. For example, on Earth, the large amount of oxygen in our atmosphere is that ‘smoking gun’.

We’re a long way off having that much insight into GJ 1132b, but the fact that we’ve detected its atmosphere at all is a good first step.

The planet orbits the not-too-distant red dwarf star Gliese 1132, which Southworth and his team studied using the ESO/MPG telescope in Chile.

They measured the slight dip in brightness across seven wavelengths of light as GJ1132b passed in front of its host star every 1.6 Earth days, in order to get a better idea of the size and composition of the planet.

They were surprised to find that the planet appeared larger when observed in one type of infrared wavelength of light, which suggests that the planet has an atmosphere that’s opaque to these wavelengths.

The team went on to model different possible versions of this atmosphere, and found that an atmosphere rich in water and methane could explain what they were seeing.

Prior to this, the only exoplanets that researchers have detected atmospheres around were planets that were more than eight times more massive than Earth, and gas giants similar to Jupiter.

“With this research, we have taken the first tentative step into studying the atmospheres of smaller, Earth-like, planets,” said Southworth. “The planet is significantly hotter and a bit larger than Earth, so one possibility is that it is a ‘water world’ with an atmosphere of hot steam.”

The type of star GJ 1132b is orbiting also makes the planet of particular interest – its host star is a low-mass red dwarf, which are incredibly common throughout the Universe and are frequently found to host small, Earth-like planets.

But they’ve also been shown to be particularly active, often blasting huge solar flares out at their surrounding planets – something previous research has suggested would evaporate any traces of a planet’s atmosphere.

But the new discovery suggests that an atmosphere is possible of enduring this bombardment for billions of years without being destroyed – which opens up the possibility that thousands more planets orbiting low-mass stars could potentially harbour atmospheres.

“Given the huge number of very low-mass stars and planets, this could mean that the conditions suitable for life are common in the Universe,” a press release explains.

We still have a lot to learn about GJ 1132b, and hopefully we’ll have some more answers soon – the new discovery makes it one of the highest-priority targets to be studied by instruments such as the Hubble Space Telescope, the Very Large Telescope, and the James Webb Space Telescope, which is scheduled to launch in 2018.

Source:sciencealert.com

Bad news, humans: TRAPPIST-1 is not the alien paradise we were hoping for – ScienceAlert


Our newly discovered ‘sister solar system’ – a seven-planet conga line orbiting an ultra-cool dwarf star called TRAPPIST-1 – has been hailed as a potentially habitable pocket of the Universe, flush with liquid water and temperate climates, and only 39 light-years away.

But the closer we look, the less ‘alien-friendly’ this star system appears, with scientists now finding that TRAPPIST-1 is so volatile, either its three ‘Earth-like’ planets have one hell of a magnetosphere, or we’re looking at yet another set of uninhabitable worlds.

 

A team led by astronomer Krisztián Vida from Konkoly Observatory in Hungary has been analysing luminosity patterns in the raw photometric data of TRAPPIST-1, obtained during the K2 mission of NASA’s Kepler space telescope.

Over an 80-day period, they clocked 42 high-energy flares blasting from TRAPPIST-1, including five that were ‘multi-peaked’ eruptions, meaning they gave off several bursts of energy in one go.

The strongest eruption the team identified was about as powerful as the largest flare we’ve ever witnessed from our own Sun – the infamous Carrington Event of 1859, which if it happened today, would devastate global communication systems.

At the time, the flare sent electrical surges through telegraph lines, and gave rise to aurorae so bright, they woke up gold miners in the Rocky Mountains, fooling them into thinking it was morning.

But if life on Earth can withstand flares like the Carrington Event, why can’t hypothetical aliens on TRAPPIST-1’s three Earth-like planets?

The first thing to consider is that the average time between these flares was just 28 hours, so we’re talking serious and near-constant bombardment here.

 And the researchers go so far as to say the solar storms caused by TRAPPIST-1 ‘s flares would be hundreds or thousands of times more powerful than the storms that hit Earth.

According to a separate study released last year, it would take 30,000 years for a planet’s atmosphere to stablise after one of these powerful flares – so they’re not getting much done in just 28 hours.

On top of all of that, the planets in the TRAPPIST-1 star system are much closer to their star than we are to our Sun.

That means this relentless bombardment would likely destroy any stability in their atmospheres, making it very difficult for even the most primitive life to get a foothold.

“The frequent strong flares of TRAPPIST-1 are probably disadvantageous for hosting life on the orbiting exoplanets, as the atmospheres of the exoplanets are constantly altered and cannot return to a steady state,” the team concludes.

Just to drive this depressing point home even further, Evan Gough over at Universe Today points out that Earth’s robust magnetic field protects us from the worst parts of the Sun’s flares, but it’s unlikely the TRAPPIST-1 planets have the same shield up.

This study suggests that planets like those in the TRAPPIST system would need magnetospheres of tens to hundreds of Gauss, whereas Earth’s magnetosphere is only about 0.5 Gauss,” says Gough.

“How could the TRAPPIST planets produce a magnetosphere powerful enough to protect their atmosphere?”

So things aren’t looking so great for our sister solar system.

And while we’ve pretty much gotten used to the emotional roller coaster that is the search for life elsewhere in the Universe, this is a tough one, because remember that Google Doodle of our new planet friends?

planets-google

They just look like such a cool hang.

One thing to keep in mind is that the study is still undergoing peer-review, so the results might be subject to change.

But if taken alongside previous studies that have already brought the system’s habitability into question, we might have to reconsider those awesome NASA travel posters, and come up with something more… Hellscapey.

Source:sciencealert.com

NASA Studying How to Travel Faster than Light After Finding Trappist-1 ·


NASA recently reported finding a treasure trove of planets, all able to support life in a nearby solar system, called Trappist-1, according to a Harvard paper on the subject. Now, as if NASA hasn’t been using interstellar space travel for decades now, this arm of the military industrial system says it is beginning to study faster-than-light space travel.

Propulsion

Just over two years ago, NASA reported that a team may have unintentionally accelerated particles to faster-than-light speeds while using the EmDrive resonance chamber. This alone would result in faster than light travel by creating a warp bubble, something we’ve already seen depicted in episodes of Star Trek.

Then there are private companies which are said to be working on similar faster-than-light speed technologies.

Orbital ATK is working with NASA to create solar panels that can power up spaceship through its ion drives with collected sunlight, and Aerojet Rocketdyne is developing an ion thruster system, the Evolutionary Xenon Thruster-Commercial, or “NEXT-C” that would allow spaceships to travel in space three times faster than current interplanetary propulsion systems.

Meanwhile mainstream news outlets keep pumping us with the “information” that nothing can ever go faster than the speed of light, but in September of 2011, physicist Antonio Ereditato shocked the world by announcing that small particles called neutrinos had travelled faster than light, destroying Einstein’s theories of relativity.  This was supposedly discovered by compiling data from over 160 scientists working on the OPERA project.

 Of course, we have whistleblowers like Corey Goode, and William Tompkins who have been telling us that these technologies and many more have existed far longer than NASA is letting on.

Tompkins, a former employee of Douglas Aircraft has named dozens of unconventional propulsion programs that are listed within highly classified documents.

When Ben Rich, former director of Lockheed Skunkworks told us, “We already have the meansto travel among the stars but these technologies are locked up in Black Projects…and it would take an act of God to ever get them out to benefit humanity. Anything you can imagine, we already know how to do,” he wasn’t kidding, but apparently NASA still thinks we lemmings will believe that they are just now stumbling on ways to travel to Trappist-1 faster than the speed of light.

Source:http://themindunleashed.com

Astronomers aren’t sure if TRAPPIST-1’s planets are habitable after all.


But there’s still some hope!

In what is becoming a bit of a rollercoaster of emotions, it seems that at least a couple – if not all – of the seven planets in the TRAPPIST-1 solar system could have already been stripped of their atmosphere by the star’s radiation, making it unlikely that liquid water could flow on their surfaces after all.

But hold onto your tears; researchers studying TRAPPIST-1’s spectral emissions have found evidence that the star might just be young enough to not have had time to blow away their atmospheres quite yet, meaning we can still dream of life on those far distant worlds a little longer.

 Astronomers from the University of Geneva Observatory in Switzerland have compared the two types of radiation being emitted from the ultra-cool dwarf star TRAPPIST-1, and concluded the star doesn’t seem to be “extremely old”,

That brings into question just how much atmosphere still clings to the surfaces of the star’s beloved family of rocky planets.

For those of you who missed the fuss, TRAPPIST-1 is a star about 39 light-years away that was discovered to have at least three planets last year. At the time, that didn’t seem so remarkable, but then last month, NASA made a much-hyped announcement that TRAPPIST-1 actually hosted a seven-planet system

Nicknamed our sister star system, it’s believed to consist of a large family of seven small, terrestrial bodies occupying tight orbits relatively close to their star.

Last month, astronomers announced that those planets actually consisted of a large family of seven small, terrestrial bodies occupying tight orbits relatively close to the star.

Early speculation suggested that at least a few of the planets could sit within a ‘Goldilocks zone‘, where liquid water might pool on their rocky surfaces, and life could therefore have hypothetically evolved in its tepid oceans.

 The exciting news inspired NASA to release fan art and travel posters displaying planets that appeared larger than our Moon in classic sci-fi styles, all to set our imaginations blazing.

Of course, we should have prepared for broken hearts. The signs were all there.

Orbiting so close to their parent, the planets are more than likely tidally locked, meaning one hemisphere constantly faces their sun while the other side is in perpetual darkness.

Only last month, we were somewhat dismayed to learn that the nearest known planet outside our own Solar System, orbiting Proxima Centauri, is probably just a hunk of bare rock polished of any atmosphere by bursts of radiation from its red dwarf star.

In these cases, radiation from the star ionises gases in the planet’s atmosphere, allowing the particles to be pushed up and away from the planet’s surface on streams of solar wind.

Last year, astronomers considered whether TRAPPIST-1 was another rather temperamental parent, calculating that the inner planets might have lost as much as 15 Earth-oceans of water to this solar scouring effect over the course of their lifetime.

Of course, it would depend on what “lifetime” meant.

In this most recent research, astronomers compared two types of radiation emitted from the dwarf star: X-rays shed by the star’s wispy corona, and ultra-violet light called Lyman-alpha radiation, which comes from the hydrogen atoms from the chromosphere layer just beneath the corona.

It seems TRAPPIST-1 emits less than half as much Lyman-alpha radiation as Proxima Centauri, which is to be expected, since it’s a cooler star.

But the two stars emit about the same amount of X-rays, which, all things considered, is kind of odd, since the X-ray and ultra-violet radiation output for this category of star both decrease over time, with the X-rays fading a lot faster.

“The fact that TRAPPIST-1 emits nearly three times less flux at Lyman-alpha than in the X-ray would thus suggest it is still relatively young,” the researchers write in their paper.

With a fair bit of hand-waving, it seems that “relatively young” could mean anything up from about half a billion years old.

The fact that it spins quite quickly also adds weight to the conclusion that it’s not an extremely old star.

Yet it also means the X-ray emissions were stronger in the past, since they have decreased over time.

Since it’s predicted that the blasts of radiation would blow away any Earth-like atmosphere from the inner two planets within 1 to 3 billion years, and could take between 5 and 22 billion years to strip the rest of the family, there could still yet be liquid water up on those rocks if TRAPPIST-1 is indeed little older than 500 million years old.

There’s further hope in the fact that the spacing of the planets indicates the possibility they migrated in close to their sun from further out in the solar system, subjecting them to intense blasts of radiation for even less time.

“If they migrated within a disk, typical time scales are about 100 million years, but that may not be valid for a system like TRAPPIST-1,” researcher Vincent Bourrier told Camille M. Carlisle at Sky and Telescope. “Uncharted territory here!”

TRAPPIST-1 is a bit of an odd duck, however; in spite of seeming young, its motion through space places it within an older crowd of stars, which is either coincidence or a sign that there is more to learn.

If you still feel any love for our distant dwarf star, NASA just released footage of changes in its brightness taken over an hour period on 22 February, providing a snapshot of one of its planets passing in front the star and dimming its light.

TRAPPIST-1 animation

While a block of blinking pixels might not seem all that exciting, keep in mind this animated image covers just 44 square arcseconds of the sky, which is about the same area as a grain of sand held at arm’s length.

So hold back from ripping down that fabulous TRAPPIST-1e poster … for now. The Brady Bunch of stars is weird enough that it might still have a few secrets up its sleeve.

NASA Just Released the Raw Data From its Latest Observations of our ‘Sister Solar System’


You see what they see.

A few weeks ago, NASA announced the discovery of seven, Earth-sized planets orbiting a star just 39 light-years away.

Known as the TRAPPIST-1 star system, the seven planets appear to be rocky, have life-friendly surface temperatures, and could potentially harbour liquid water – leading scientists to nickname it a ‘sister solar system’ to our own, and a pretty good spot to look for extraterrestrial life.

 Since then, researchers have debated how habitable these planets could really be, given the stellar activity of the dwarf star they orbit.

But the truth is, until we get a closer look, no one can say for sure whether or not life could be supported somewhere in the star system. Which is why NASA has just rushed out data from its latest and longest observations of TRAPPIST-1 to date.

The initial discovery of the star system was made over several months last year, using a combination of NASA’s Spitzer Space Telescope and ground-based telescopes.

But since 15 December 2016, NASA’s had its own planet-hunting Kepler space telescope trained on TRAPPIST-1 for follow-up observations. And this week, they’ve made all that additional data freely available to the scientific community and public to trawl through. (Note: you need Python-based Kadenza software to extract the raw data files.)

In total, the observation period, which was part of Kepler’s K2 Campaign, provided 74 days of monitoring, which is the longest, nearly continuous set of observations of TRAPPIST-1 to date.

Unfortunately, we can’t tell you exactly what’s in that gold mine of data just yet, because in its current state, it’s totally raw and uncalibrated, and it’s going to take weeks for scientists to make sense of what Kepler has seen.

 But this early release gives scientists an opportunity to get more insight into the gravitational interaction between the planets – a clue to whether any of them are tidally locked – as well as the chance to spot any planets that may remain undiscovered in the system.

Interestingly, TRAPPIST-1 wasn’t on Kepler’s original list of systems to study last year. But in May 2016, when the discovery of the first three planets orbiting the star was announced, NASA decided to point it towards the constellation Aquarius, home of the TRAPPIST-1 system, to get a closer look.

Specifically, Kepler monitored minuscule changes in the star’s brightness as the seven planets orbit in front of it.

That kind of ‘dimming data’ can give astronomers insight into the size and mass of the planets passing in front of their host star, and will hopefully help them nail down the orbital period of the seventh planet, which until now has only been observed passing in front of its star once.

The observations could also reveal information about the magnetic activity of the host star, which would greatly affect its habitable zone. That’s why they’ve rushed out the data’s release – NASA usually waits until its data has been processed before it gives us a look.

“Scientists and enthusiasts around the world are invested in learning everything they can about these Earth-size worlds,” said Geert Barentsen, K2 research scientist at NASA’s Ames Research Centre.

“Providing the K2 raw data as quickly as possible was a priority to give investigators an early look so they could best define their follow-up research plans. We’re thrilled that this will also allow the public to witness the process of discovery.”

And it’s not just for the public’s benefit – astronomers around the world are currently preparing proposals for where we should aim Earth-based telescopes next winter, which are due by the end of March.

Telescope spots are hard to secure, so the new TRAPPIST-1 data will hopefully give researchers enough ammo to convince regulatory bodies that they should be given time to observe the star system in the coming months.

If the raw data means very little to you – and, let’s face it, if you’re not used to looking at this type of data, it’s like another language – don’t worry. NASA plans to finish processing the data by late May, and will release a ‘translated’ version then, hopefully with some exciting discoveries for us.

Although Kepler observations are amazing, what the scientific community is even more excited about is the launch of the James Webb Space Telescope next year, which will be powerful enough to actually detect the atmospheric composition of the TRAPPIST-1 system.

In the meantime, thanks to this freely available data, it could be a member of the public who stumbles across the next big discovery in the star system, and that’s pretty awesome.

Nasa’s ‘holy grail’: Entire new solar system that could support alien life discovered


It is ‘amazing’ how similar the entire solar system is to Earth.

Scientists have found a new solar system filled with planets that look like Earth and could support life, Nasa has announced.

At least three of the seven planets represent the “holy grail for planet-hunting astronomers”, because they sit within the “temperate zone” and are the right temperature to allow alien life to flourish, the researchers have said. And they are capable of having oceans, again suggesting that life could flourish on them.

No other star system has ever been found to contain so many Earth-sized and rocky planets, of the kind thought to be necessary to contain aliens.

The researchers might soon be able to find evidence of life on the planets, they have said. British astronomer Dr Chris Copperwheat, from Liverpool John Moores University, who was part of the international team, said: “The discovery of multiple rocky planets with surface temperatures which allow for liquid water make this amazing system an exciting future target in the search for life.”

Co-researcher Dr Amaury Triaud, of the Institute of Astronomy in Cambridge, said: “We hope we will know if there’s life there within the next decade.”

Even if life isn’t ever found near TRAPPIST-1, it might eventually develop there. The star is relatively young – even when our own Sun has run out of fuel and our solar system is destroyed, the newly-discovered one will still be in its early infancy.

TRAPPIST-1 “burns hydrogen so slowly that it will live for another 10 trillion years – more than 700 times longer than the Universe has existed so far, which is arguably enough time for life to evolve”, wrote Ignas AG Snellen from the Leiden Observatory, in an accompanying article about the discovery.How the new solar system that could support life would actually look

All of the planets were found using a method called “transit photometry”. That works by watching out for when a planet passes, or transits, in front of its host star – blocking out a small amount of light, allowing us to see the planet and learn about its size.

Scientists first found the star TRAPPIST-1 in 2010, after monitoring the smallest stars close to the Sun. Since then, they have been watching out for those transits – and after seeing 34 of them clearly, they proposed that they can be attributed to the seven new planets.

They then worked to understand the size and composition of each of the worlds. That work is still continuing, but the researchers believe that the planets have large oceans, are temperate and other conditions that could make way for alien life.

 The Seven Wonders of Trappist-1

Dr Michael Gillon, from the STAR Institute at the University of Liege in Belgium, said: “This is an amazing planetary system – not only because we have found so many planets, but because they are all surprisingly similar in size to the Earth.”

If a person were on one of the planets, everything would look a lot darker than usual, the scientists said. The amount of light heading to your eye would be about 200 times less than you get from the sun, and would be comparable to what you can see at sunset.

Despite that relative darkness, everything would still feel warm, the researchers said. That’s because roughly the same amount of energy would be coming from the star as warms our Earth – but it does so infrared.

Because the star is so dim in relative terms, all of the planets are warmed enough to sit in the temperate zone. That’s despite the fact that they are all so close to it – each of them sitting nearer to the star than Mercury, the planet in our solar system that orbits closest to the Sun.

“The spectacle would be beautiful,” said Amaury Triaud, one of the scientists involved in the research. “Every now and then you’d see another planet, about as big as another moon in the sky.”

The sun would also look about 10 times bigger than our own does from Earth, Dr Triaud said, despite the fact that it is in fact only 8 per cent as big. And it would be a sort of salmon pink, said Dr Triaud, who noted that the scientists initially thought it would be a deep reddish crimson but most of that red light would be infrared and so invisible.

pia21425.jpg
This chart shows, on the top row, artist conceptions of the seven planets of TRAPPIST-1 with their orbital periods, distances from their star, radii and masses as compared to those of Earth. The bottom row shows data about Mercury, Venus, Earth and Mars

It’s unlikely that any possible life that is on the planet would actually see this way, the scientists noted, since they would probably have evolved entirely different eyes – or perhaps none at all.

The researchers hope that they can do more work to watch the planets and learn more about their character. They want to look in particular at the seventh, outermost planet because at the moment they are not sure how it interacts with the inner ones.

Nasa’s Hubble Space Telescope is already being used to search for atmospheres around the planets. Future telescopes, including the the European Extremely Large Telescope and James Webb Space Telescope, may be powerful enough to detect markers of life such as oxygen in the atmospheres of exoplanets.

The first exoplanet was found in 1992. Since then, astronomers have detected more than 3,500 of the worlds, distributed across 2,675 star systems.

About a fifth of the sun-like stars are thought to have Earth-sized planets close enough to them to support life.

 Further details on the 7 newly discovered planets

In all, there might be 40 billion potentially habitable words sitting just in our galaxy, the Milky Way, astronomers estimate.

Scientists have long thought that Earth-sized planets were abundant, but the new research shows just how many of them there might be. Many of those planets might never be seen, because they don’t pass in front of their host star and so aren’t visible.

That might mean that the new system is actually not all that out of the ordinary. Scientists expect that for each planet we find, there are as many as 100 we can’t see – and so the scientists might not actually have been lucky, but rather seen something that wasn’t that unusual.

NASA Announces the Discovery of a Potentially Habitable ‘sister Solar System’


7 Earth-sized planets orbiting a single star.

In one of the most significant exoplanet discoveries to date, NASA just announced that not one, but seven Earth-sized planets have been found orbiting the habitable or ‘temperate zone’ of a star just 39 light-years away.

Research suggests at least the inner six planets appear to have Earth-like masses, are made of rock, and have surface temperatures ranging between a life-friendly 0 to 100°C (32 to 212°F). NASA is calling it a ‘sister solar system’ to our own, and says several of the planets could potentially host liquid water, and maybe even extraterrestrial life.

 NASA made the announcement in a live press conference after triggering much speculation over their big “discovery beyond our Solar System”.

The new exoplanets have been detected orbiting an ultracool dwarf star called TRAPPIST-1, which is located about 39 light-years away from our Sun in the Aquarius constellation.

Astronomers led by Michaël Gillon from the University of Liège in Belgium first detected three exoplanets around the star back in May 2016, using Earth-based telescopes.

But it wasn’t until the team studied it more closely using NASA’s Spitzer space telescope that they discovered an additional four planets in the system.

Initial estimates based on these observations suggest that at least five of the planets have masses similar to Earth, and follow-up observations by the Hubble Space Telescope indicate that they probably have rocky compositions.

 At least three also appear to fall within the temperate zone of their star – which means their surface temperatures are most likely to be between 0 and 100°C (32 and 212°F), making liquid water, and potentially even some form of extraterrestrial life, a possibility.

Because of the system’s structure, it’s also possible that any of the planets have liquid water.

The European Space Observatory is calling it “the most incredible star system to date”.

Image-2.-Credit.-NASA.JPL-Caltech

Before we get too excited, the researchers stress that there’s still a lot more research and analysis to be done – particularly on the seventh, outermost planet, which has only been observed orbiting the star once.

Because of that, we still don’t know how long that seventh planet takes to orbit TRAPPIST-1, or how it interacts with the inner planets.

And the entire system is so far away, we can’t say for sure as yet whether it hosts water, or is a good place for life to exist.

But from what the researchers can tell, not only are at least three of the planets potential homes to liquid oceans, the entire system actually seems to be have a lot in common with our own.

“The TRAPPIST-1 system is a compact analogue of the inner Solar System,” the authors write in Nature.

You can see a comparison of the inner Solar System compared to the TRAPPIST-1 system below:

Image-6.-Credit.-IoA.Amanda-Smith

But despite the familiarities to home, there are some big differences between our systems.

Mainly the fact that TRAPPIST-1 is only a little bigger than Jupiter, and its planets orbit only a little farther apart than Jupiter’s moons.

The whole system is pretty compact too, with the closest planet only taking 1.5 days to orbit its star. The sixth planet takes 13 days.

That means that if you were standing on the surface of one of these planets, the neighbouring planets in the sky would at times appear larger than our Moon does to us.

Imagine something like this:

Image-3.-Credit.-NASA.JPL-Caltech

Because of this, it’s thought that the planets might all affect each other, and could even be tidally locked, with one face constantly pointed towards their star, in the same way that Jupiter’s moons always have one side locked towards the giant planet.

That tidal locking could also do some strange things to the temperature gradients on the planet, which NASA says makes it possible that liquid water could exist on any of them under the right conditions.

But perhaps even more exciting about this discovery is what it means for the likelihood of other Earth-like planets out there in our galaxy.

“In the past few years, evidence has been mounting that Earth-sized planets are abundant in the Galaxy, but Gillon and collaborators’ findings indicate that these planets are even more common than previously thought,” Ignas A. G. Snellen, an astronomer from the Leiden University in the Netherlands who wasn’t involved in the research, writes in an accompanying opinion piece in Nature.

He explains the significance in more detail:

“From geometric arguments, we expect that for every transiting planet found, there should be a multitude of similar planets (20 to 100 times more) that, seen from Earth, never pass in front of their host star.

Of course, the authors could have been lucky, but finding seven transiting Earth-sized planets in such a small sample suggests that the Solar System with its four (sub-)Earth-sized planets might be nothing out of the ordinary.”

For now, we can only speculate on what these seven incredible Earth-like worlds would be like. But the best part about all of this is that in the not-so-distant future, we might actually be able to know more.

With the NASA James Webb Space Telescope scheduled to come online next year, researchers should be able to get a better idea of the composition and atmosphere of this sister solar system.

And when the European Space Organisation’s Extremely Large Telescope goes live in 2024, it should actually be able to detect water on the distant worlds from right here on Earth.

If you want the wonder of this discovery put into perspective, here’s Sean Carey, the manager of NASA’s Spitzer Science Centre, to fill you with awe about the galaxy we live in:

The research has been published in Nature.

You can see our live updates from during the briefing below:

12.50pm ET: Okay, here we go! Who else is excited.

12.51pm ET: Here’s what we know so far. All NASA has said is that the press conference will “present new findings on planets that orbit stars other than our Sun, known as exoplanets”.

The briefing participants are:

  • Thomas Zurbuchen, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington
  • Michael Gillon, astronomer at the University of Liege in Belgium
  • Sean Carey, manager of NASA’s Spitzer Science Centre at Caltech/IPAC, Pasadena, California
  • Nikole Lewis, astronomer at the Space Telescope Science Institute in Baltimore
  • Sara Seager, professor of planetary science and physics at Massachusetts Institute of Technology, Cambridge.

12.57pm ET: NASA is doing well with the suspense this morning…

12.58pm ET: I love that 20,000 other people around the world are live streaming the conference right now, too. Hi guys!

1pm ET: We’re live!

1.03pm ET: NASA has discovered not just one, but seven exoplanets similar to Earth orbiting a single star! Whoa.

1.05pm ET: Thomas Zurbuchen: “I’m in awe today … There are actually seven Earth-sized planets orbiting the nearby TRAPPIST-1 star about 40 light-years away. Three of these planets are in the habitable zone where liquid water could pool on the surface.”

1.06pm ET: “For the first time we’ve found this many terrestrial planets around a single star… The discovery gives us a hint that finding a second Earth is not just a matter of it, but when,” said Zurbuchen.

1.09pm ET: Sean Carey: “This is the most exciting disovery we’ve had yet wih Spizter in almost 14 years of discovery.”

1.14pm ET: They’ve made a new NASA travel poster for the star system already!

1.15pm ET: Sara Seager is telling us that the fact that all the planets in the TRAPPIST-1 system are potential hosts of liquid water means it’s an incredibly exciting target to study and visit further. If one planet isn’t “quite right” its sister might be.

1.18pm ET: Thomas thinks the worlds will be far more beautiful than the illustrations we can come up with. “The fact that there are other worlds out there just like the Earth and have some commonality with the Earth … these questions about ‘are we alone’ are being answered in these decades and the next decades.”

1.19pm ET: Q&A time!

1.21pm ET: Most questions asking about the number of exoplanets that are potentially habitable that we’ve found so far, and whether we have confirmation of water on the TRAPPIST-1 planets as yet. Answer: no, but we’re looking.

1.22pm ET: TRAPPIST-1 is a very young star, so it should have more longevity than our own Sun.

1.23pm ET: Oh good question, do the planets have any names as yet? Nothing official, but they’ve got some ideas… Interestingly, there’s no official way to give names to exoplanets like we do asteroids.

1.24pm ET: We’re not sure if the planets have moons as yet.

1.26pm ET: Fascinating question about whether these planets might all have the same biosphere because they’re so close together. We don’t know as yet, but it’s something worth investigating.

1.30pm ET: Okay, our site went down for a while there, guys. Thanks for the patience, and thanks for watching with us!

NASA’s Stunning Discovery: Seven Earth-Like Planets Orbiting A Star Just 40 Light Years Away


They’re calling it a “holy grail” in the quest for earth-like planets suspected to have alien life. And NASA just revealed that it has found the strongest candidates that fit that description yet, right here in our solar neighbourhood.

NASA Trappist-1 solar system 40 lightyears away

NASA DISCOVERED TRAPPIST-1 SOLAR SYSTEM 40 LIGHTYEARS AWAY

NASA announced in a press conference just now that it’s Spitzer Space Telescope made the discovery of seven planets orbiting a super cool, dwarf star called TRAPPIST-1 which is just 40 light years away from where we are.

 That’s not all. What’s amazing about this NASA discovery is that at least three out of the seven planets are claimed to be present in the goldilocks, habitable zone — the ideal distance away from the sun, just so that the planet’s surface isn’t too hot or cold, giving life the maximum possible chance of flourishing. Just like our earth sits at an ideal distance away from our sun — not too near, not too far, just right.

NASA said, “Around a nearby, cold, small star we found 7 rocky Earth-size planets, all of which could have liquid water – key to life as we know it.” This discovery is unprecedented in history, for never before have so many planets have been found at once, and that too orbiting a sun in the habitable zone. It’s unreal!

Scientists associated with the discovery are optimistic about one thing. Even if the seven or three newly discovered planets do not have life now, chances of life evolving on them are very high.

Scientists discover three ‘potentially habitable’ planets


An international team of scientists said today they had discovered a trio of Earth-like planets that are the best bet so far for finding life outside our solar system.

The three orbit an ultracool dwarf star a mere 39 light years away, and are likely comparable in size and temperature to Earth and Venus, they reported in a study, published in Nature.

The three orbit an ultracool dwarf star a mere 39 light years away. Image for representation

“This is the first opportunity to find chemical traces of life outside our solar system,” said lead author Michael Gillon, an astrophysicist at the University of Liege in Belgium.

All three planets had the “winning combination” of being similar in size to Earth, “potentially habitable” and close enough so their atmospheres can be analysed with current technology, he told AFP.

The find opens up a whole new “hunting ground” for habitable planets, he added.

Gillon and colleagues calibrated a 60-centimetre telescope in Chile, known as TRAPPIST, to track several dozen dwarf stars neither big nor hot enough to be visible with optical telescopes.

They zeroed in on a particularly promising one – now known as TRAPPIST-1 – about one eighth the size of the Sun, and significantly cooler.

Observing it for months, the astronomers noticed that its infrared signal faded slightly at regular intervals, evidence of objects in orbit.

Further analysis confirmed they were exoplanets – planets revolving around stars outside our solar system.

The innermost two circle their dwarf star every 1.5 and 2.4 days, though they are hit with only four and two times the amount of heat-generating radiation that Earth receives from the Sun.

The more distant orbit of the third planet takes between four and 73 days, according to the study.

“So far, the existence of such ‘red worlds’ orbiting ultra-cool dwarf stars was purely theoretical, but now we have not just one lonely planet but three,” said co-author Emmanuel Jehin, also from the University of Liege.

He called the discovery a “paradigm shift” in the search for life elsewhere in the universe.

Given their size and proximity to their low-intensity star, all three planets may have regions at temperatures within a range suitable for sustaining liquid water and life, the study concluded.
Their proximity to Earth means scientists will be able to find out a lot more.

“These planets are so close, and their star so small, we can study their atmosphere and composition,” said co-author Julien de Wit, a postdoc at the Massachusetts Institute of Technology (MIT.)

“This is a jackpot for the field,” he said in a statement, adding that it should be possible to determine if they harbour life “within our generation.”

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