Scientists say they found first potentially habitable planet with water in its skies - National Post - Canadanewsmedia
Connect with us

Science

Scientists say they found first potentially habitable planet with water in its skies – National Post

Published

on


In the dim, red light of an alien sun, scientists have found the first evidence for water in the atmosphere of a rocky planet – offering a tantalizing new target in the search for life in the universe.

The intriguing world, which goes by the impersonal designation K2-18b, lies 110 light-years away in the constellation Leo. More important: It sits in its star’s “habitable zone,” where it is bathed in the right amount of warmth to allow for liquid water on its surface.

Twice as large as our own planet and eight times as massive, K2-18b possesses powerful gravity that would make it difficult to walk upon. It orbits close to a red dwarf star, much smaller and cooler than our sun. And aside from water vapour, its atmosphere contains mostly hydrogen gas – a molecule that makes up less than 1 part per million of our own atmosphere.

It is no “second Earth,” said astronomer Angelos Tsiaras, the lead author of a study on the planet published Wednesday in the journal Nature Astronomy. But he believes it is “the best candidate for habitability that we know right now.”

The paper by Tsiaras draws on publicly available data produced by Björn Benneke, a planetary astronomer at the University of Montreal in Canada. On Tuesday, Benneke’s team posted its own analysis of K2-18b on the preprint server arXiv, which hosts academic papers not yet published in peer-reviewed journals.

Benneke and his colleagues also found signatures of water vapour in K2-18b’s skies. But they were less optimistic than Tsiaras about the potential habitability of this world. The Montreal-based team’s interpretation of its data suggests the hydrogen atmosphere forms a thick, gaseous envelope around the planet. This would generate intense pressures at the planet’s surface – perhaps enough to push hydrogen into a liquid form.

It’s definitely the smallest and coolest planet that we’ve had a glimpse into the atmosphere of so far …. But I don’t think it’s potentially habitable

“It is not a true Earth analogue,” the researchers report.

Laura Kreidberg, an astronomer at the Harvard-Smithsonian Center for Astrophysics, said that K2-18b might be better described as a “mini-Neptune” than a “super Earth.” Extensive research with computer models suggests that, at 1.6 to 1.8 times the mass of Earth, planets tend to become huge and gaseous, rather than rocky.

Though K2-18b is likely solid at its core, the temperatures and pressures at the “surface” would be so high that few complex molecules would survive, let alone any life forms.

“I think the result is amazing,” said Kreidberg. “It’s definitely the smallest and coolest planet that we’ve had a glimpse into the atmosphere of so far …. But I don’t think it’s potentially habitable.”

Scientists had detected water only in the atmospheres of “gas giants” — huge exoplanets that lack solid surfaces, much like Jupiter and Saturn in our solar system. Rocky exoplanets are smaller, making them harder to find and more difficult to study. Even a planet like K2-18b can be examined only with humanity’s most sensitive space telescope — the Hubble.

When K2-18b was discovered in 2015, Tsiaras and his colleagues thought it would be a good candidate for a form of analysis called transit spectroscopy, which involves studying the changes in a star’s light as a planet “transits,” or passes in front of it.

The planet is so close to its cool host star that it takes just 33 days to orbit. So, month after month, the researchers waited with Hubble to capture the moment of transit.

As the starlight filtered through the planet’s atmosphere, some of it would be absorbed by the gases in the planet’s air. By separating the light into its component parts, the scientists could look for signatures of particular molecules.

What they found suggests that the composition of K2-18b’s atmosphere could range from 0.1 percent water vapor (about the proportion in Earth’s upper atmosphere) to a whopping 50 percent. (At its highest, water vapor concentration in Earth’s lower atmosphere is about 4 percent.)

The Hubble isn’t sensitive to the right types of light to detect other important molecules, such as nitrogen or methane, so the researchers can only speculate about the precise composition of the atmosphere. The planet could have thick clouds, like Venus, that would heat its surface to an intolerable degree. Or its atmosphere might be so thin and insubstantial that it offers no protection from the perils of space, like the atmosphere of Mars.

Researchers must wait for more sophisticated tools, such as the long-delayed James Webb Space Telescope, to reveal more details about the distant world.

Yet Giovanna Tinetti, a colleague of Tsiaras’s at University College London and a co-author of the Nature study, suggested it’s still possible that there is liquid water somewhere below the atmosphere.

“We’re going to need more observations,” she said. “We need to know much more about the planet.”

I can tell you from personal experience how disturbing it is to discover a website devoted to making fake audio clips of you — for comic or malevolent purposes
In the 1960s, severe autism was thought to affect up to 10 children in 10,000. By 2014, it was one child in 59. But diagnostic criteria are more loosely applied
‘Such a solution seems to be a bit — well — nuts!’ Ending global warming at the expense of the human race seems loopy to William Reville, a former prof …
While someone might eat a Beyond Meat burger for ethical reasons, it does little for that person’s health. In fact, it might be more harmful than good

Let’s block ads! (Why?)



Source link

Continue Reading

Science

SpaceX's Next Starship Prototype Taking Shape (Photos) – Space.com

Published

on

By


SpaceX’s next Starship prototype won’t be just a concept vehicle for much longer.

Construction of the test craft is proceeding apace, as two new photos posted on Twitter today (Sept. 17) by company founder and CEO Elon Musk reveal. 

One of the images shows the vehicle — apparently Starship Mk1, which is being assembled at SpaceX’s South Texas facility, near the village of Boca Chica — in the background, standing behind a building that contains a variety of parts and other equipment. (SpaceX is also building a similar prototype, called Starship Mk2, at the company’s Florida facilities, reasoning that a little intracompany competition will improve the vehicle’s final design.)

Related: SpaceX’s Starship and Super Heavy Mars Rocket in Pictures

“Droid Junkyard, Tatooine,” Musk said via Twitter, referring to Luke Skywalker’s home planet in the “Star Wars” movies. 

The other photo is a close-up view of a ring-shaped section being lowered onto the Mk1’s body. The billionaire entrepreneur had a joky caption for this one as well: “Area 51 of Area 51.”

The Mk1 and Mk2 follow in the footsteps of SpaceX’s Starhopper vehicle, which was retired after acing a big test flight last month. But the new vehicles are far more ambitious and more capable. Whereas Starhopper sported just a single Raptor engine and stayed within a few hundred feet of the ground, for example, the Mk1 and Mk2 will be powered by at least three Raptors and will go much higher.

SpaceX is aiming for a test flight that gets 12 miles (20 kilometers) up in October, followed by an orbital attempt “shortly thereafter,” Musk said late last month.

All of these steps are leading toward the final Starship, SpaceX’s planned Mars-colonizing craft. That Starship will be capable of carrying 100 passengers and will launch atop a huge rocket called the Super Heavy. Both of the elements, rocket and spaceship, will be fully and rapidly reusable, Musk has said.

The final Starship, as currently envisioned, will sport six Raptors, while the Super Heavy will be powered by 35 of the engines. Those numbers could change, however; Musk is scheduled to give a Starship design update on Sept. 28 from the South Texas site.

The Mk1 should be fully assembled by that time, he has said.

The Mk1 and Mk2 test campaigns won’t be terribly lengthy, if SpaceX’s planned schedules hold. Company representatives have said that the first operational flights of Starship, which are likely to be commercial satellite launches, could come as early as 2021. (Eventually, SpaceX plans to use Starship for all the company’s spaceflight needs, from interplanetary colonization missions to satellite launches to point-to-point trips around Earth.)

And SpaceX is targeting 2023 for a crewed mission of the vehicle: a flight around the moon booked by Japanese billionaire Yusaku Maezawa.

Mike Wall’s book about the search for alien life, “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Could We Intercept Interstellar Comet C/2019 Q4 Borisov? – Universe Today

Published

on

By


When ‘Oumuamua passed through our Solar System two years ago, it set off a flurry of excitement in the astronomical community. Here was the first-ever interstellar object that be observed by human trackers, and the mysteries surrounding its true nature and composition led to some pretty interesting theories. There were even some proposals for a rapid mission that would be able to rendezvous with it.

And now that a second interstellar object – C/2019 Q4 (Borisov) – has been detected traveling through the Solar System, similar proposals are being made. One of them comes from a group of scientists from the Initiative for Interstellar Studies (i4is) in the UK. In a recent study, they assess the technical feasibility of sending a mission to this interstellar comet using existing technology, and found that there were a few options!

In many ways, C/2019 Q4 (Borisov) represents an opportunity to conduct the kinds of research that were not possible with ‘Oumuamua. When that mystery object was first observed, it had already made its closest pass to the Sun, past Earth, and was on its way out of the Solar System. Nevertheless, what we were able to learn about ‘Oumuamua led to the conclusion that it was an entirely new class of celestial object.

Artist’s impression of the first interstellar asteroid/comet, “Oumuamua”. This unique object was discovered on Oct. 19th, 2017, by the Pan-STARRS 1 telescope in Hawaii. Credit: ESO/M. Kornmesser

In addition to those who ventured that it was either a comet or an asteroid, there were also those who theorized that ‘Oumuamua could be a fragment from a comet that exploded when passing close to our Sun, or even an extra-terrestrial solar sail. Another interesting find was the fact that similar objects likely pass through our Solar System on a regular basis (many of which stay).

For these reasons, a mission that could study such objects up close is very desirable. As Dr. Andreas M. Hein – the executive director of i4is’s board of directors, the chairman of its Technical Research Committee, and one of the co-authors on the recent study – told Universe Today via email:

“Investigating interstellar objects from a close distance would provide us with unique data about other star systems without actually flying to them. They might provide unique insights into the evolution and composition of other star systems and exoplanets in them. Interstellar objects are cool as it’s a bit like: If you can’t go to the mountain, let the mountain come to you. It will likely take many decades until we can send a spacecraft to another star. Hence, interstellar objects might be an intermediate solution for finding out more about other stars and their planets.”

What’s more, he claims, these objects have probably been travelling between star system for hundreds of thousands (or even millions) of years. As a result, they undoubtedly picked up material along the way or bear the marks of encounters with other objects or forces. In short, their composition and surface features can tell us a great deal about what is out there in the interstellar medium.

Artist’s illustration of a light-sail powered by lasers generated on the surface of a planet. Credit: M. Weiss/CfA

This is not the first time that i4is has proposed sending a spacecraft to rendezvous with an interstellar object. In 2017, Dr. Hein and several colleagues from i4is (who also co-authored this study) produced a paper titled “Project Lyra: Sending a Spacecraft to 1I/’Oumuamua (former A/2017 U1), the Interstellar Asteroid“, which was conducted with the help of the asteroid-prospecting company Asteroid Initiatives LLC.

The project was so-named because of ‘Oumuamua’s origins, which astronomers concluded came from the general direction of Vega – the brightest star in the northern constellation of Lyra. After taking into account the speed with which ‘Oumuamua was leaving the Solar System at the time – 26 km/s (93,600 km/h; 58,160 mph) – they determined that any proposal would be a trade-off between three factors.

These included when a mission could launch, the velocity it could achieve, and the time it would take to rendezvous with the object. Under the circumstances, they felt that the best option was to wait for future technological breakthroughs – such as those being pursued by Breakthrough Starshot (a concept for a laser-driven interstellar solar sail).

These conclusions have proven very applicable, thanks to the detection of a second interstellar object passing through our Solar System in as many years. In their most recent study, the research team once again used Optimum Interplanetary Trajectory Software (OITS) – which was developed by team-member Adam Hibberd – to assess all available options for sending a spacecraft to rendezvous with an interstellar object.

The Falcon Heavy's first flight. Each time the Heavy lifts off, it uses roughly 440 tons of fuel. Image: SpaceX
The Falcon Heavy’s first flight. Each time the Heavy lifts off, it uses roughly 440 tons of fuel. Image: SpaceX

These included the optimal launch vehicle (like NASA’s Space Launch System (SLS) or SpaceX’s Falcon Heavy) the optimal trajectory for the mission, and the best type of spacecraft. In the end, they determined that humanity has the capability of rendezvousing with an interstellar object using existing technology and came up with a mission architecture that could make that happen.

This mission would rely on a heavy-launch vehicle and could alternately employ a 2 ton (1.8 metric ton) or a 3 kg (6.6 lbs) CubeSat spacecraft. Depending on when it launched and what its preferred trajectory would be, it might also need to conduct a Jupiter flyby and Solar Oberth maneuver to catch up with C/2019 Q4 (Borisov). As Dr. Hein explained:

“Our results show that for both, ‘Oumuamua and C/2019 Q4 (Borisov), we already have the technology to visit these objects. Regarding ‘Oumuamua, we can launch a spacecraft towards it even beyond the year 2030. There is plenty of time to develop such a spacecraft. The case for C/2019 Q4 (Borisov) is a bit more tricky, as it is faster than ‘Oumuamua. But even for this object, we could have sent a two-ton spacecraft to it with a Falcon Heavy, if we would have launched it in 2018.”

“Later missions are also possible, but require a bigger launcher. Future telescopes will be able to detect such objects much earlier and with adequate preparation, we can send a spacecraft on an encounter mission. So we have the technology to do this and with the discovery of C/2019 Q4 (Borisov), we also know that we probably have plenty of opportunities to fly to such an object.”

Artist’s impression of the interstellar object, `Oumuamua, experiencing outgassing as it leaves our Solar System. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

Once again, the presence of an interstellar object in our Solar System is a major source of excitement. In addition to all the opportunities to learn from them, C/2019 Q4 and ‘Oumuamua are encouraging because of the implication their presence has. Not only do they confirm that objects from distant stars pass through our System pretty regularly; they also show that we are at a point where we can detect, track and study them.

But knowing that in the future, we will be able to study them up close is especially exciting! In fact, the ESA is currently working on a mission that could very be the one to rendezvous with a future interstellar object. It’s known as the Comet Interceptor, a “fast-class” concept consisting of three spacecraft that will wait in space until a pristine comet appears, rapidly catch up with it!

“We imagine two types of research,” Dr. Hein said. “First, remote-sensing, for example with a telescope taking pictures. Second, we can analyze material from the object directly by shooting an impactor into it and catching some of the particles from the dust plume which is generated with the main spacecraft. This would provide unique insights into the composition of the object.”

As for what this research could reveal, Dr. Hein has some thoughts on that too: “I can only speculate but we might see evidence that organic molecules, the building blocks for life, actually travel between star systems and who knows, maybe life itself might actually spread between stars in our galaxy.”

Further Reading: arXiv

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Physicists at MIT Shave Estimate of Mass of Neutrino “Ghost Particle” in Half – SciTechDaily

Published

on

By


KATRIN’s spectrometer, shown here, precisely measures the energy of electrons emitted in the decay of tritium, which has helped scientists come closer to pinning down the mass of the ghost-like neutrino. Credit: The KATRIN Collaboration

Joseph Formaggio explains the discovery that the ghostly particle must be no more than 1 electronvolt, half as massive as previously thought.

An international team of scientists, including researchers at MIT, has come closer to pinning down the mass of the elusive neutrino. These ghost-like particles permeate the universe and yet are thought to be nearly massless, streaming by the millions through our bodies while leaving barely any physical trace.

The researchers have determined that the mass of the neutrino should be no more than 1 electron volt. Scientists previously estimated the upper limit of the neutrino’s mass to be around 2 electron volts, so this new estimate shaves down the neutrino’s mass range by more than half.

The new estimate was determined based on data taken by KATRIN, the Karlsruhe Tritium Neutrino Experiment, at the Karlsruhe Institute of Technology in Germany, and reported at the 2019 Conference on Astroparticle and Underground Physics last week. The experiment triggers tritium gas to decay, which in turn releases neutrinos, along with electrons. While the neutrinos are quick to dissipate, KATRIN’s sequence of magnets directs tritium’s electrons into the heart of the experiment — a giant 200-ton spectrometer, where the electrons’ mass and energy can be measured, and from there, researchers can calculate the mass of the corresponding neutrinos.

Joseph Formaggio, professor of physics at MIT, is a leading member of the KATRIN experimental group, and spoke with MIT News about the new estimate and the road ahead in the neutrino search.

Q: The neutrino, based on KATRIN’s findings, can’t be more massive than 1 electron volt. Put this context for us: How light is this, and how big a deal is it that the neutrino’s maximum mass could be half of what people previously thought?

A: Well, that’s somewhat of a difficult question, since people (myself included) don’t really have an intuitive sense of what the mass is of any particle, but let’s try. Consider something very small, like a virus. Each virus is made up of roughly 10 million protons. Each proton weighs about 2,000 times more than each electron inside that virus. And what our results showed is that the neutrino has a mass less than 1/ 500,000 of a single electron!

Let me put it another way. In each cubic centimeter of space around you, there are about 300 neutrinos zipping through. These are remnants of the early universe, just after the Big Bang. If you added up all the neutrinos residing inside the sun, you’d get about a kilogram or less. So, yeah, it’s small.

Q: What went into determining this new mass limit for the neutrino, and what was MIT’s role in the search?

A: This new mass limit comes from studying the radioactive decay of tritium, an isotope of hydrogen. When tritium decays, it produces a helium-3 ion, an electron, and an antineutrino. We actually never see the antineutrino, however; the electron carries information about the neutrino’s mass. By studying the energy distribution of the electrons ejected at the highest energies allowed, we can deduce the mass of the neutrino, thanks to Einstein’s equation, E=mc2.

However, studying those high-energy electrons is very difficult. For one thing, all the information about the neutrino is embedded in a tiny fraction of the spectrum — less than 1 billionth of decays are of use for this measurement. So, we need a lot of tritium inventory. We also need to measure the energy of those electrons very, very precisely. This is why the KATRIN experiment is so tricky to build. Our very first measurement presented today is the culmination of almost two decades of hard work and planning.

MIT joined the KATRIN experiment when I came to Boston in 2005. Our group helped develop the simulation tools to understand the response of our detector to high precision. More recently, we have been involved in developing tools to analyze the data collected by the experiment.

Q: Why does the mass of a neutrino matter, and what will it take to zero in on its exact mass?

A: The fact that neutrinos have any mass at all was a surprise to many physicists. Our earlier models predicted that the neutrino should have exactly zero mass, an assumption dispelled by the discovery that neutrinos oscillate between different types. That means we do not really understand the mechanism responsible for neutrino masses, and it is likely to be very different than how other particles attain mass. Also, our universe is filled with primordial neutrinos from the Big Bang. Even a tiny mass has a significant impact on the structure and evolution of the universe because they are so aplenty.

This measurement represents just the beginning of KATRIN’s measurement. With just about one month of data, we were able to improve previous experimental limits by a factor of two. Over the next few years, these limits will steadily improve, hopefully resulting in a positive signal (rather than just a limit). There are also a number of other direct neutrino mass experiments on the horizon that are also competing to reach greater sensitivity, and with it, discovery!

Let’s block ads! (Why?)



Source link

Continue Reading

Trending