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The Most Common Stars in Our Galaxy May Be More Habitable Than We Thought

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Red dwarf stars are the most common kind of star in our neighbourhood, and probably in the Milky Way. Because of that, many of the Earth-like and potentially life-supporting exoplanets we’ve detected are in orbit around red dwarfs. The problem is that red dwarfs can exhibit intense flaring behaviour, much more energetic than our relatively placid Sun.

 

So what does that mean for the potential of those exoplanets to actually support life?

Most life on Earth, and likely on other worlds, relies on stellar energy to survive. The Sun has been the engine for life on Earth since the first cells reproduced. But sometimes, like all stars, the Sun acts up and emits flares.

Sometimes it emits extremely energetic flares. The powerful magnetic energy in the Sun’s atmosphere becomes unstable, and an enormous amount of energy is released. If it’s released towards Earth, it can cause problems. It can lead to disruptions in radio communications and even blackouts.

But in terms of flaring activity, the Sun is relatively weak compared to some other stars. Some stars, especially red dwarfs, can flare frequently and violently. A team of researchers studied how flaring activity affects the atmosphere and potential for life on Earth-like planets orbiting low-mass stars, including M-type stars, K-type stars, and G-type stars.

Art of a flaring red dwarf star, orbited by an exoplanet. (NASA/ESA/G. Bacon/STScI)Art of a flaring red dwarf star, orbited by an exoplanet. (NASA/ESA/G. Bacon/STScI)

The new study is called “Persistence of flare-driven atmospheric chemistry on rocky habitable zone worlds“. The lead author is Howard Chen, a PhD student at Northwestern University. The paper is published in the journal Nature Astronomy.

“Our Sun is more of a gentle giant,” said Allison Youngblood, an astronomer at the University of Colorado at Boulder and co-author of the study.

 

“It’s older and not as active as younger and smaller stars. Earth also has a strong magnetic field, which deflects the Sun’s damaging winds.”

That helps explain why Earth is positively “rippling with life” as Carl Sagan described our planet. But for planets orbiting low-mass stars like red dwarfs (M-dwarfs) the situation is much different.

We know that solar flares and associated coronal mass ejections can be very damaging to the prospects of life on unprotected exoplanets. The authors write in their introduction that “[s]tellar activity – which includes stellar flares, coronal mass ejections (CMEs) and stellar proton events (SPEs) – has a profound influence on a planet’s habitability, primarily via its effect on atmospheric ozone.”

A single flare here and there over time doesn’t have much effect. But many red dwarfs exhibit more frequent and prolonged flaring.

“We compared the atmospheric chemistry of planets experiencing frequent flares with planets experiencing no flares. The long-term atmospheric chemistry is very different,” said Northwestern’s Howard Chen, the study’s first author, in a press release.

“Continuous flares actually drive a planet’s atmospheric composition into a new chemical equilibrium.”

 

One of the things the team looked at was ozone, and the effect flares have on it. Here on Earth, our ozone layer helps protects us from the Sun’s UV radiation. But extreme flaring activity on red dwarfs can destroy ozone in the atmosphere of planets orbiting close to it.

When ozone levels drop, a planet is less protected from UV radiation coming from its star. Powerful UV radiation can diminish the possibility of life.

In their study, the team used models to help understand flaring and its effects on exoplanet atmospheres. They used flaring data from NASA’s TESS (Transiting Exoplanet Survey Satellite) and long-term exoplanet climate data from other studies. They found some cases where ozone persisted, despite flaring.

“We’ve found that stellar flares might not preclude the existence of life,” added Daniel Horton, the study’s senior author. “In some cases, flaring doesn’t erode all of the atmospheric ozone. Surface life might still have a fighting chance.”

(Chen et al, 2020)(Chen et al, Nature Astronomy2020)

IMAGE: This figure from the study shows global-mean vertical profiles of atmospheric species on a simulated planet around a Sun-like G-type star. From left to right are the mixing ratios for ozone, nitrous oxide, nitric acid, and water vapour.

Planets that can support life, at least potentially, can be in a tough spot. They must be close enough to their stars to prevent their water from freezing, but not too close or they’re too hot. But this dance with proximity can expose them to the powerful flares.

 

Red dwarfs are smaller and cooler than our Sun, so that means the habitable zone for any planets orbiting them is smaller and much closer to the star than Earth is to the Sun. That not only exposes them to flares but leads to planets being tidally locked to their stars.

The combination of flaring and tidal-locking can be bad for life’s prospects. Earth’s rotation generates its protective magnetosphere, but tidally-locked planets can’t generate one and are largely unprotected from stellar UV radiation.

“We studied planets orbiting within the habitable zones of M and K dwarf stars – the most common stars in the universe,” Horton said.

“Habitable zones around these stars are narrower because the stars are smaller and less powerful than stars like our Sun. On the flip side, M and K dwarf stars are thought to have more frequent flaring activity than our Sun, and their tidally locked planets are unlikely to have magnetic fields helping deflect their stellar winds.”

(Chen et al, 2020)(Chen et al, 2020)

IMAGE: This figure from the study shows how repeated stellar flaring can alter the atmospheric gases in a simulated Earth-like planet around a Sun-like star.

There’s a more positive side to this study as well. The team found that flaring activity can actually help the search for life.

The flares can make it easier to detect some gases which are biomarkers. In this case, they found energy from flaring can highlight the presence of gases like nitric acid, nitrous dioxide, and nitrous oxide, which can all be indicators of living processes.

(Chen et al, 2020)(Chen et al, 2020)

IMAGE: This figure from the study shows how repeated stellar flaring can affect the atmospheric chemistry on a modelled Earth-like planet around a K-type star. Note the raised levels of detectable NO, a potential bio-marker.

“Space weather events are typically viewed as a detriment to habitability,” Chen said.

“But our study quantitatively showed that some space weather can actually help us detect signatures of important gases that might signify biological processes.”

But only some. In other cases, their work showed that flaring can destroy potential biosignatures from anoxic life.

“Although we report the 3D effects of stellar flares on oxidizing atmospheres, strong flares could have other unexpected impacts on atmospheres with reducing conditions. For instance, hydrogen oxide species derived from stellar flares could destroy key anoxic biosignatures such as methane, dimethyl sulfide and carbonyl sulfide, thereby suppressing their spectroscopic features,” the authors report.

Another interesting result of this study concerns exoplanet magnetospheres. They find that hyperflares may help reveal the nature and extent of magnetospheres.

“More speculatively, proton events during hyperflares may reveal the existence of planetary-scale magnetic fields by highlighting particular regions of the planet. By identifying nitrogen- or hydrogen oxide-emitting flux fingerprints during magnetic storms and/or auroral precipitation events, one may be able to determine the geometric extent of exoplanetary magnetospheres.”

(Chen et al, 2020)(Chen et al, 2020)

IMAGE: Hyperflares might help us understand the extent of exoplanet magnetospheres by identifying the extent of nitrogen oxide flux fingerprints.

Other recent research has suggested that exoplanets subjected to flaring, especially around red dwarf stars, are not great locations to search for life. The flaring activity is too detrimental. But this study shows that there’s more complexity to the situation.

Overall it shows that flaring could help us detect biosignatures in some cases. It also shows that while flaring can disrupt exoplanet atmospheres, in many cases they return to normal. It’s also a fact that low-mass stars live much longer than stars like our Sun, meaning there’s more time for life to develop on their planets.

This new work highlights how complicated the search for life is, and how many variables are involved. And it contains at least one surprise. Whereas flaring has been largely considered detrimental to exoplanet habitability, the fact that it may help detect biosignatures means there’s more going on than expected.

This research required cooperation from scientists across many disciplines. It relied on climate scientists, astronomers, observers and theorists, and of course, exoplanet scientists.

“This project was a result of fantastic collective team effort,” said Eric T. Wolf, a planetary scientist at CU Boulder and a co-author of the study.

“Our work highlights the benefits of interdisciplinary efforts when investigating conditions on extrasolar planets.”

This article was originally published by Universe Today. Read the original article.

 



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Astronomers Find an Astonishing ‘Super-Earth’ That’s Nearly as Old as The Universe

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It turns out that planets can live a very long time indeed.

Around one of the galaxy’s oldest stars, an orange dwarf named TOI-561 just 280 light-years away, astronomers have found three orbiting exoplanets – one of which is a rocky world 1.5 times the size of Earth, whipping around the star on a breakneck 10.5-hour orbit.

 

Obviously an exoplanet so close to its star isn’t likely to be habitable, even if it is rocky like Earth, Venus and Mars. It would have a temperature of 2,480 Kelvin, tidally locked with a magma ocean on the permanent day side.

But the TOI-561 system, planets and all, is one of the oldest ever seen, at an estimated age of around 10 billion years.

That’s more than twice as old as the Solar System, nearly as old as the Universe itself, and evidence that rocky exoplanets can remain stable for a very long time.

“TOI-561 b is one of the oldest rocky planets yet discovered,” said astronomer Lauren Weiss of the University of Hawai’i.

“Its existence shows that the universe has been forming rocky planets almost since its inception 14 billion years ago.”

The three planets, named TOI-561 b, TOI-561 c and TOI-561 d, were identified by NASA’s planet-hunting space telescope, TESS. TESS stares at sections of the sky, looking for periodic, faint dips in the light of distant stars. These are transits, when a planet passes between us and its star.

 

From this data, and follow-up observations, astronomers were able to determine the orbital periods and sizes of the three exoplanets.

TOI-561 d, the outermost, is around 2.3 times the size of Earth, with an orbital period of 16.3 days. TOI-561 c is 2.9 times the size of Earth, with an orbital period of 10.8 days. And TOI-561 b is 1.45 times the size of Earth, with an orbital period of just over 10.5 hours.

The team also conducted radial velocity measurements. As planets orbit a star, that star doesn’t sit still. Each exoplanet exerts its own gravitational tug on the star, resulting in a little complex dance that compresses and stretches the star’s light as it moves towards and away from us as we observe it.

If we know the mass of the star, we can observe how much the star moves in response to an exoplanet’s gravitational tugging and calculate the mass of the exoplanet. From this, the researchers calculated that TOI-561b is about three times the mass of Earth.

But its density is about the same as Earth’s, about five grams per cubic centimetre.

 

“This is surprising because you’d expect the density to be higher,” said planetary astrophysicist Stephen Kane of the University of California, Riverside. “This is consistent with the notion that the planet is extremely old.”

That’s because the heavier elements in the Universe – metals heavier than iron – are forged in the hearts of stars, in the supernovae at the end of a massive star’s life, and collisions between massive dead stars. Only once stars have died and spread these elements out into space can they be taken up into other objects.

So, the very oldest stars in the Universe are very poor in metals. TOI-561, for instance, is low in metallicity. And any planets that formed in the earlier Universe should likewise have low metallicity.

Previous research has suggested that there is a lower metallicity limit for rocky planet formation, since heavier elements are less likely to be evaporated by stellar radiation, the grains surviving long enough in the circumstellar disc to clump together and form planets.

Finding planets like TOI-561 b can help constrain those models, which in turn could help us locate more ancient rocky exoplanets.

“Though this particular planet is unlikely to be inhabited today,” Kane said, “it may be a harbinger of a many rocky worlds yet to be discovered around our galaxy’s oldest stars.”

And this can aid us in the search for habitable worlds. Earth is around 4.5 billion years old; the earliest signs of life are thought to be about 3.5 billion years old. And yet vertebrates didn’t appear on the fossil record until about 500 million years ago, give or take.

Complex life as we know it takes time to emerge. So if we want to find life more complex than archaea or microbes, planets that are long-lived and relatively stable will be, scientists think, the most likely to be hospitable.

So while TOI-561 b wouldn’t be a nice place to visit, it constitutes yet another clue that could help us in our avid search for other life out there in the Universe.

The team’s research was presented at the 237th meeting of the American Astronomical Society. It has also been accepted into The Astronomical Journal, and is available on arXiv.

 



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Starlink Satellites Are Now Invisible to The Naked Eye, But Astronomers Still See Them

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SpaceX is on course to rocket tens of thousands of satellites into Earth’s orbit, part of Elon Musk‘s plan to blanket the planet in high-speed internet. For the first time, data shows that the company may be able to accomplish this feat without marring everyone’s view of the night sky.

 

When the first bright trails of the company’s Starlink satellites paraded across the night in May 2019, scientists feared that it was a preview of a future in which points of moving light swarm the skies and overshadow the stars.

But Starlink may now be largely invisible to the naked eye, according to a new analysis. The paper suggests that new sun-visors added to the most recent 415 satellites SpaceX has launched may have significantly darkened them.

The visors deploy after launch and block sunlight from reflecting off the satellites’ shiniest surfaces.

These “VisorSats,” as SpaceX calls the satellites with this built-in feature, are on average 31 percent as bright as the 540 Starlink satellites that came before them, according to the paper.

The research, which was based on 430 observations of satellites flying overhead, was published Saturday on the open repository ArXiv.

However, this visor improvement still leaves the satellites about 2.5 times brighter than SpaceX’s goal, and they’re still far too bright for telescopes to be unaffected. The visors probably won’t prevent Starlink from permanently changing ground-based astronomy.

“It’s a win, but not a complete victory,” Jonathan McDowell, an astronomer at the Centre for Astrophysics at Harvard and Smithsonian, told Business Insider.

 

“It’s a win for the worry about changing the night sky for the average person,” he added. “I think we’ve avoided that fate.”

But for telescopes, the skies could still be swarming with false stars in just a few years, making it nearly impossible to get a clear look at the cosmos. That could hamper efforts to study celestial bodies and protect the Earth from deadly asteroids.

SpaceX has launched more than 950 Starlink satellites into Earth’s orbit over the last two years. Early iterations of the internet service have provided broadband-like performance in rural America.

The company has permission from the Federal Communications Commission to rocket 12,000 satellites into orbit by mid-2027. Its filings suggest a long-term plan involving 42,000 spacecraft; 20 times the total number of working satellites pre-Starlink.

SpaceX did not respond to a request for comment and has not shared its own data on the VisorSats’ brightness.

Starlink satellites are photobombing telescope observations

In the new analysis, engineer Tony Mallama calculated that the visored Starlink satellites have a magnitude, or brightness, of 5.92. This means that under certain conditions, you could still see them with the naked eye.

“In most circumstances, even in fairly dark sites, they’re going to be just below naked-eye visibility; or most of them are,” McDowell said.

 

SpaceX has said its minimum goal is to get the satellites to magnitude 7, which would be more than 2.5 times darker than they are now and well below naked-eye visibility.

But even then, Starlink could still photobomb telescope observations and ruin astronomers’ data.

A single satellite can create a continuous streak of light across a telescope’s long-exposure images of the sky, blocking the objects astronomers want to study. Satellites can especially affect telescopes that observe objects close to the horizon near dawn; and those are the observations that help astronomers track asteroids flying close to Earth.

“Some projects really won’t mind this. Other projects we’ll have to really rethink, and some will be impossible,” McDowell previously told Business Insider.

Satellites also broadcast radiowaves and emit invisible wavelengths of light, like infrared. That can interfere with telescopes that use those waves to observe the Universe.

Even for Earth-orbiting space telescopes like Hubble, the satellites may frequently streak across a field of view and ruin hard-won images of deep space.

“We’re in a new phase of space utilization. It’s a new space industrial revolution, things are different, and astronomy’s going to be affected,” McDowell said in August.

“We just have to make sure we’re part of the conversation so we can keep it down to the ‘pain in the neck’ level and not the ‘give up and go home’ level.”

 

Satellite regulations don’t take astronomy into account

Musk has said the Starlink service could eventually fund SpaceX missions to Mars. But the company isn’t the only one planning a constellation of satellites.

Companies like Amazon and OneWeb aim to establish their own fleets of thousands of satellites, and a Chinese company called GW has filed a proposal to launch a constellation of nearly 13,000 satellites.

McDowell is particularly concerned about OneWeb, which has proposed sending its satellites to a much higher altitude than Starlink. That would make them visible for longer portions of the night. If that project goes forward as planned, McDowell said, it will be “pretty impossible” to do most ground-based observations during the summer.

OneWeb satellites will appear about as bright as SpaceX’s VisorSats, according to Mallama’s analysis.

The FCC, which authorizes the flight and use of internet satellites in the US, has said that preventing disruption to astronomy is “not a condition” for licensing.

McDowell said he would like to see the FCC, the Federal Aviation Administration, and the United Nations hammer out satellite regulations that would take such impacts into consideration.

“There’s some relief that, yeah, they did manage to make their Starlinks a little less bright. And that was nice that they chose to work with the community, ” McDowell said.

“But it doesn’t take away the need for a more regulatory approach; a global regulatory approach.”

This article was originally published by Business Insider.

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Astronomers Have Identified Another Important Aspect of Planets That Could Host Life

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We are, by now, pretty familiar with the concept of the Goldilocks zone. Also known as the habitable zone, it’s the distance from a star at which liquid water can be present on the surface on a planet – not so hot as to be vaporised, nor so cold as to be frozen.

 

These conditions matter because we count liquid water as a vital ingredient for life. But it’s not the only criterion that can help us to assess a planet’s potential habitability; according to new research based on decades of data, there are also Goldilocks stars.

Not all stars, you see, are built alike. Some are extremely hot and bright – such as the very young, blazing blue OB stars. Some are quite low in temperature, like red M-type dwarfs. These could perhaps be a good temperature, but the Goldilocks zone would be very close to the star, and red dwarfs tend to be turbulent, lashing their surrounding space with violent flares.

Our Sun sits between these two extremes, what is known as a yellow dwarf – a G-type main-sequence star. But, although we know life has emerged in the Solar System (we are, after all, living it), not even the Sun is a Goldilocks star.

Nope. According to astronomers at Villanova University, the best stars for life are one step along the Hertzsprung-Russell chart of star types – that is, K-type stars, which are orange stars a little cooler than the Sun, and a little warmer than a red dwarf.

 

“K-dwarf stars are in the ‘sweet spot,’ with properties intermediate between the rarer, more luminous, but shorter-lived solar-type stars (G stars) and the more numerous red dwarf stars (M stars),” explained Villanova astronomer and astrophysicist Edward Guinan.

“The K stars, especially the warmer ones, have the best of all worlds. If you are looking for planets with habitability, the abundance of K stars pump up your chances of finding life.”

Together with a colleague, astronomer Scott Engle of Villanova University, they presented their research at the 235th meeting of the American Astronomical Society back in January 2020.

Let’s be clear here: astronomers are not looking for habitable planets to find a back-up Earth. Even if we did find Earth 2.0, we just don’t have the technology to get us there.

Our quest for Goldilocks planets has more to do with finding out if there is other life out there in the Universe – and, one step further, if there is intelligent life. Is life normal, or is Earth a giant freak? Narrowing down where life is likely to spring up can help us in that search.

 

Guinan, Engle and others have been monitoring a number of stars F to G-type stars in ultraviolet and X-rays over the last 30 years as part of their Sun in Time program, and M-type red dwarfs for 10 years for the Living with a Red Dwarf program.

Both these programs have been helping to assess the impact of X-ray and ultraviolet radiation of the stars in question on the potential habitability of their planets.

Recently, they expanded their research to include similar data collection on K-type stars – what they have called Living with Goldilocks K-dwarfs. And, indeed, these stars do seem to be the most promising for life-supporting conditions.

goldilocks stars(NASA/ESA/Z. Levy/STScI)

Although the habitable zone of K-type stars is smaller, they are much more common than G-type stars, with around 1,000 of them within just 100 light-years of the Solar System. And they have much longer main-sequence lifetimes.

The Sun is around 4.6 billion years old, with a main-sequence lifetime of around 10 billion years. Complex life only emerged on Earth around 500 million years ago, and scientists think that, in another billion years, the planet will become uninhabitable as the Sun begins to expand, pushing the Solar System’s habitable zone outwards.

 

Red dwarfs are more common, but they’re feisty, subjecting the space around them to intense radiation and flare activity that could strip any close planets of their atmospheres and liquid water.

By contrast, K-type stars have lifetimes between 25 and 80 billion years, offering a much bigger window in which life can emerge than G-type stars; according to the team’s data, they are much calmer than red dwarfs, too.

And there are already K-type stars around which planets have been located – namely Kepler-442, Tau Ceti and Epsilon Eridani

“Kepler-442 is noteworthy in that this star (spectral classification, K5) hosts what is considered one of the best Goldilocks planets, Kepler-442b, a rocky planet that is a little more than twice Earth’s mass,” Guinan said

“So the Kepler-442 system is a Goldilocks planet hosted by a Goldilocks star!”

The search for life could, of course, be much more complicated even than this – for example, if the planet has a highly elliptical orbit, it could produce temperature extremes that would render an otherwise Goldilocks planet uninhabitable.

The location of other planets in the system could make a difference too; and there’s a possibility that the entire galaxy has its own habitable zone (if it does, we know we’re in it, so looking nearby is a good start).

But this research could represent a piece of the puzzle that could make the life needle in the space haystack just a little bit easier to find.

The research was presented at the 235th meeting of the American Astronomical Society in Hawaii.

A version of this article was first published in January 2020.

 



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An Astronomer Who Believes in Aliens Explains Why He’s Not Convinced by UFO Sightings

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If intelligent aliens visit the Earth, it would be one of the most profound events in human history.

Surveys show that nearly half of Americans believe that aliens have visited the Earth, either in the ancient past or recently. That percentage has been increasing. Belief in alien visitation is greater than belief that Bigfoot is a real creature, but less than belief that places can be haunted by spirits.

 

Scientists dismiss these beliefs as not representing real physical phenomena. They don’t deny the existence of intelligent aliens. But they set a high bar for proof that we’ve been visited by creatures from another star system. As Carl Sagan said, “Extraordinary claims require extraordinary evidence.”

I’m a professor of astronomy who has written extensively on the search for life in the universe. I also teach a free online class on astrobiology. Full disclosure: I have not personally seen a UFO.

Unidentified flying objects

UFO means unidentified flying object. Nothing more, nothing less.

There’s a long history of UFO sightings. Air Force studies of UFOs have been going on since the 1940s. In the United States, “ground zero” for UFOs occurred in 1947 in Roswell, New Mexico. The fact that the Roswell incident was soon explained as the crash landing of a military high-altitude balloon didn’t stem a tide of new sightings.

The majority of UFOs appear to people in the United States. It’s curious that Asia and Africa have so few sightings despite their large populations, and even more surprising that the sightings stop at the Canadian and Mexican borders.

 

Most UFOs have mundane explanations. Over half can be attributed to meteors, fireballs and the planet Venus. Such bright objects are familiar to astronomers but are often not recognized by members of the public. Reports of visits from UFOs inexplicably peaked about six years ago.

Many people who say they have seen UFOs are either dog walkers or smokers. Why? Because they’re outside the most. Sightings concentrate in evening hours, particularly on Fridays, when many people are relaxing with one or more drinks.

A few people, like former NASA employee James Oberg, have the fortitude to track down and find conventional explanations for decades of UFO sightings. Most astronomers find the hypothesis of alien visits implausible, so they concentrate their energy on the exciting scientific search for life beyond the Earth.

Are we alone?

While UFOs continue to swirl in the popular culture, scientists are trying to answer the big question that is raised by UFOs: Are we alone?

Astronomers have discovered over 4,000 exoplanets, or planets orbiting other stars, a number that doubles every two years. Some of these exoplanets are considered habitable, since they are close to the Earth’s mass and at the right distance from their stars to have water on their surfaces.

 

The nearest of these habitable planets are less than 20 light years away, in our cosmic “back yard.” Extrapolating from these results leads to a projection of 300 million habitable worlds in our galaxy.

Each of these Earth-like planets is a potential biological experiment, and there have been billions of years since they formed for life to develop and for intelligence and technology to emerge.

Astronomers are very confident there is life beyond the Earth. As astronomer and ace exoplanet-hunter Geoff Marcy, puts it, “The universe is apparently bulging at the seams with the ingredients of biology.” There are many steps in the progression from Earths with suitable conditions for life to intelligent aliens hopping from star to star.

Astronomers use the Drake Equation to estimate the number of technological alien civilizations in our galaxy. There are many uncertainties in the Drake Equation, but interpreting it in the light of recent exoplanet discoveries makes it very unlikely that we are the only, or the first, advanced civilization.

This confidence has fueled an active search for intelligent life, which has been unsuccessful so far. So researchers have recast the question “Are we alone?” to “Where are they?”

 

The absence of evidence for intelligent aliens is called the Fermi Paradox. Even if intelligent aliens do exist, there are a number of reasons why we might not have found them and they might not have found us.

Scientists do not discount the idea of aliens. But they aren’t convinced by the evidence to date because it is unreliable, or because there are so many other more mundane explanations.

Modern myth and religion

UFOs are part of the landscape of conspiracy theories, including accounts of abduction by aliens and crop circles created by aliens. I remain skeptical that intelligent beings with vastly superior technology would travel trillion of miles just to press down our wheat.

It’s useful to consider UFOs as a cultural phenomenon. Diana Pasulka, a professor at the University of North Carolina, notes that myths and religions are both means for dealing with unimaginable experiences. To my mind, UFOs have become a kind of new American religion.

So no, I don’t think belief in UFOs is crazy, because some flying objects are unidentified, and the existence of intelligent aliens is scientifically plausible.

But a study of young adults did find that UFO belief is associated with schizotypal personality, a tendency toward social anxiety, paranoid ideas and transient psychosis. If you believe in UFOs, you might look at what other unconventional beliefs you have.

I’m not signing on to the UFO “religion,” so call me an agnostic. I recall the aphorism popularized by Carl Sagan, “It pays to keep an open mind, but not so open your brains fall out.” The Conversation

Chris Impey, University Distinguished Professor of Astronomy, University of Arizona.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 



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Here’s How to Watch Hayabusa2 Drop Off Its ‘Treasure Box’ of Asteroid Dust

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A Japanese spacecraft is set to return from its asteroid-blasting mission on Saturday. In a dramatic finale, the Hayabusa2 spacecraft is expected to send at least 100 milligrams of alien space rock plummeting into the Australian outback.

 

The sample comes from asteroid Ryugu: a primitive, half-mile-wide rock that zips through our solar system up to 131 million miles (211 million kilometers) from the sun.

The Japan Aerospace Exploration Agency (JAXA) launched Hayabusa2 in 2014 with the goal of collecting the first sample of material from below an asteroid’s surface.

The spacecraft first landed on Ryugu in February to collect shallow samples from the surface. But scientists knew that probing deeper could reveal more pure rock from the beginnings of our solar system, since that material hasn’t been exposed to harsh radiation from the sun.

So in April 2019, Hayabusa2 blasted a 33-foot (10-meter) crater into the asteroid using a copper plate and a box of explosives. That loosened rocks and exposed material below the surface.

Three months later, in July 2019, the probe lowered itself to Ryugu once again and scooped up the debris.

Now, the probe has almost completed the 5.5-million-mile (9-million-kilometer) journey home.

Sometime between 12 p.m. and 1 p.m. ET on Saturday, the spacecraft will shoot a capsule containing the samples toward Earth.

A bright fireball will streak across the sky as the “treasure box,” as JAXA calls it, plummets through the atmosphere at 7.5 miles per second.

 

About 6 miles above the ground, the capsule should deploy parachutes and drift to the desert floor of Woomera, Australia. Then it will send out a beacon to lead JAXA’s retrieval team to its location.

Hayabusa2, meanwhile, will embark on an 11-year extended mission to rendezvous with another asteroid, called 1998 KY26.

‘Clues to the origin of life on Earth’

Asteroids accumulated from the leftover crumbs of our early solar system, 4.5 billion years ago.

Material that didn’t make it into the planets coalesced. So what scientists find in those primitive space rocks can reveal a lot about the solar system’s history.

What’s more, Ryugu is a C-type asteroid, which means it’s rich with organic carbon molecules, water, and possibly amino acids – the building blocks for proteins that were essential to the evolution of life on Earth.

Some theories posit that an asteroid first delivered amino acids to our planet.

“Organic materials are the origins of life on Earth, but we still don’t know where they came from,” Makoto Yoshikawa, a Hayabusa2 project mission manager, said in a briefing on Friday, according to The Guardian.

“We are hoping to find clues to the origin of life on Earth by analyzing details of the organic materials brought back by Hayabusa2.”

 

NASA and JAXA are each bringing home asteroid samples to share

NASA sent its own spacecraft to an asteroid this year: Osiris-Rex (short for the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer).

The probe high-fived asteroid Bennu on October 20, landing on its surface for just six seconds to stir up dust. In that brief landing, it collected a whopping 2 pounds of samples.

That spacecraft won’t return with its bounty until 2023.

But combined, the samples from Osiris-Rex and Hyabusa2 will provide the world’s first comprehensive set of pristine asteroid material.

NASA and JAXA have agreed to share bits of their samples with each other for scientific study.

Portions of both agencies’ asteroid samples will also be stored for future research.

“These samples returned from Bennu will also allow future planetary scientists to ask questions we can’t even think of today and to be able to use analysis techniques that aren’t even invented yet,” Lori Glaze, the director of NASA’s Planetary Science Division, said in a briefing after Osiris-Rex collected its samples.

Watch JAXA’s live coverage of its first asteroid-sample return, starting 12 p.m. ET on Saturday:

This article was originally published by Business Insider.

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Chinese Probe Heads Back to Earth With First Moon Rocks Collected in 40 Years

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A Chinese space probe has lifted off from the surface of the Moon to return to Earth, an ambitious effort to bring back the first lunar samples in four decades.​

Beijing is looking to catch up with the US and Russia after taking decades to match its rivals’ achievements and has poured billions into its military-run space programme.

 

The Chang’e-5 spacecraft, named after the mythical Chinese Moon goddess, left the Moon at 1510 GMT Thursday, said China’s space agency.

A module carrying lunar rocks and soil was launched into orbit by a powerful thrust engine, officials said of the mission that landed Tuesday on the Moon.

Video footage from China’s state broadcaster CCTV showed the probe taking off from the surface of the Moon in a bright burst of light.

The space agency said that “before lift-off, the Chinese flag was raised on the moon’s surface”.

It added that this was the first time that China had achieved take-off from an extraterrestrial body.​

The module then must undergo the delicate operation of linking up with the part of the spacecraft that is to bring the specimens back to Earth, official news agency Xinhua reported.​

Scientists hope the samples will help them learn about the Moon’s origins, formation, and volcanic activity on its surface.

If the return journey is successful, China will be only the third country to have retrieved samples from the Moon, following the United States and the Soviet Union in the 1960s and 1970s.

 

Space dreams

This is the first such attempt since the Soviet Union’s Luna 24 mission in 1976.

The spacecraft’s mission was to collect two kilograms (4.5 pounds) of material in an area known as Oceanus Procellarum – or “Ocean of Storms” – a vast, previously unexplored lava plain, according to the science journal Nature.​

Xinhua, which called Chang’e-5 “one of the most complicated and challenging missions in Chinese aerospace history“, reported the probe worked for about 19 hours on the Moon.​

The samples were to be returned to Earth in a capsule programmed to land in northern China’s Inner Mongolia region, according to US space agency NASA.

​Under President Xi Jinping, plans for China’s “space dream”, as he calls it, have been put into overdrive.

China hopes to have a crewed space station by 2022 and eventually send humans to the Moon.

China launched its first satellite in 1970, while human spaceflight took decades longer – with Yang Liwei becoming China’s first “taikonaut” in 2003.​

A Chinese lunar rover landed on the far side of the Moon in January 2019 in a global first that boosted Beijing’s aspirations to become a space superpower.

The latest probe is among a slew of ambitious targets, which include creating a powerful rocket capable of delivering payloads heavier than those NASA and private rocket firm SpaceX can handle, a lunar base, and a permanently crewed space station.

China’s taikonauts and scientists have also talked up crewed missions to Mars.​ ​ ​

© Agence France-Presse

 



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On Monday You’ll Be Able to See The Full Moon Pass Through Earth’s Shadow

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Skywatchers admiring November’s full moon will also get to see another treat: a penumbral eclipse, when the Moon passes through Earth’s outer shadow, on Monday, November 30, according to NASA.

 

The Moon will be at its fullest for only a moment — on Monday, that happens at 4:30 am EST (9:30 UTC) — but the Moon will appear full for three days: from Saturday night through Tuesday morning (November 28 to December 1).  

Meanwhile, sky gazers need to remember three times to catch the penumbral eclipse: It starts before the full moon at 2:32 am EST (7:32 UTC); reaches its maximum at 4:42 am EST (9:42 UTC), when 83 percent of the Moon will be covered with Earth’s faint shadow; and ends at 6:53 a.m. EST (11:53 UTC) Monday morning, according to timeanddate.com

Penumbral eclipses are different from total or partial eclipses. During a total lunar eclipse, Earth passes directly between the sun and moon, blocking the sun’s light from reaching our natural satellite.

In contrast, during a partial eclipse, the Moon passes through part of Earth’s inner dark shadow, known as the umbra.

Finally, in a penumbral eclipse, the Moon passes through part of Earth’s outer, fainter penumbral shadow, according to Space.com, a Live Science sister site. 

Unless you’re a seasoned skywatcher, it may be challenging to see November’s penumbral eclipse, which will be visible in North America (as long as there aren’t cloudy skies), because the penumbral shadow will appear as a dim veil.

 

“The dimming of the moon during this eclipse will probably not be noticeable without instrumentation, but for spacecraft at the moon such as the Lunar Reconnaissance Orbiter (LRO), the reduction in solar power will be noticeable,” NASA wrote in a statement.

November’s full moon, known to many as the beaver moon, comes late in the month this year because October had two full moons; the second moon, a blue moon, was the first time in 76 years that a full moon was visible across the US on Halloween.

Other names for November’s full moon include the cold moon, frost moon, winter moon, oak moon, moon before Yule and child moon.

The full moon will also be celebrated during Kartik Purnima (a Hindu, Sikh and Jain cultural festival, celebrated differently by each culture), Karthika Deepam (a festival of lights observed by some Hindus), Tazaungdaing Festival Moon (observed by Bhudists in Myanmar, formerly Burma), and Ill Poya (celebrated in Sri Lanka), NASA reported. 

The beaver moon is the last full moon before the winter solstice, the shortest day of sunlight in the Northern Hemisphere, which falls on December 21 this year.

 

Other celestial sightings to look for in late November and early December include “Jupiter and Saturn, [which] will appear to gradually shift closer to each other, appearing nearer than the apparent diameter of the Moon from December 17 to 25,” NASA reported.

“They will appear at their closest, about one-fifth the diameter of the Moon, on December 21, 2020.”

People with backyard telescopes should be able to see Jupiter’s four bright moons: Ganymede, Callisto, Europa, and Io, and even Saturn’s brightly illuminated rings and Titan, its largest moon.

“Seeing Jupiter and Saturn so near each other should appear spectacular by telescope and with the naked eye,” NASA said.

To those who miss November’s moon, they can always plan to see the last full moon of 2020, which will light up the night sky at 10:28 pm EST on December 29 (3:28 UTC on December 30). 

This article was originally published by Live Science. Read the original article here.

 



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Earth Is a Whole Lot Closer to Our Galaxy’s Supermassive Black Hole Than We Thought

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It seems that Earth has been misplaced.

According to a new map of the Milky Way galaxy, the Solar System’s position isn’t where we thought it was. Not only is it closer to the galactic centre – and the supermassive hole therein, Sagittarius A* – it’s orbiting at a faster clip.

 

It’s nothing to be concerned about; we’re not actually moving closer to Sgr A*, and we’re in no danger of being slurped up. Rather, our map of the Milky Way has been adjusted, more accurately identifying where we have been all along.

And the survey beautifully demonstrates how tricky it is to map a galaxy in three dimensions from inside it.

It’s a problem that has long devilled our understanding of space phenomena. It’s relatively easy to map the two-dimensional coordinates of stars and other cosmic objects, but the distances to those objects is a lot harder to figure out.

And distances are important – they help us determine the intrinsic brightness of objects. A good recent example of this is the red giant star Betelgeuse, which turned out to be closer to Earth than previous measurements suggested. This means that it’s neither as large nor as bright as we thought.

Another is the object CK Vulpeculae, a star that exploded 350 years ago. It’s actually much farther away, which means that the explosion was brighter and more energetic, and requires a new explanation, since previous analyses were performed under the assumption it was relatively low energy.

 

But we’re getting better at calculating those distances, with surveys using the best available technology and techniques working hard to refine our three-dimensional maps of the Milky Way, a field known as astrometry. And one of these is the VERA radio astronomy survey, conducted by the Japanese VERA collaboration.

VERA stands for VLBI (Very Long Baseline Interferometry) Exploration of Radio Astrometry, and it uses a number of radio telescopes across the Japanese archipelago, combining their data to effectively produce the same resolution as a telescope with a 2,300 kilometre- (1,430 mile-) diameter dish. It’s the same principle behind the Event Horizon Telescope that produced our very first direct image of a black hole’s shadow.

VERA, which started observing in 2000, is designed to help us calculate the distances to radio-emitting stars by calculating their parallax. With its incredible resolution, it observes these stars for over a year, and watches how their position changes relative to stars that are much farther away as Earth orbits the Sun.

parallax(National Astronomical Observatory of Japan)

This change in position can then be used to calculate how far a star is from Earth, but not all parallax observations are created equal. VLBI can produce much higher resolution images; VERA has a breathtaking angular resolution of 10 millionths of an arcsecond, which is expected to produce extraordinarily high precision astrometry measurements.

And this is what astronomers have used to refine our Solar System’s position in the Milky Way. Based on the first VERA Astrometry Catalog of 99 objects released earlier this year, as well as other observations, astronomers created a position and velocity map of those objects.

 

From this map, they calculated the position of the galactic centre.

In 1985, the International Astronomical Union defined the distance to the galactic centre as 27,700 light-years. Last year, the GRAVITY collaboration recalculated it and found it closer, just 26,673 light-years away.

solar system gc(National Astronomical Observatory of Japan)

The VERA-based measurements bring it closer still, to a distance of just 25,800 light-years. And the Solar System’s orbital speed is faster, too – 227 kilometres (141 miles) per second, rather than the official velocity of 220 kilometres (137 miles) per second.

That change may not seem like much, but it could have an impact on how we measure and interpret activity in the galactic centre – ultimately, hopefully, leading to a more accurate picture of the complex interactions around Sgr A*.

Meanwhile, the VERA collaboration is forging ahead. Not only is it continuing to make observations of objects in the Milky Way, it’s joining up with an even larger project, the East Asian VLBI Network. Together, astronomers hope, the telescopes involved in this project could provide measurements of unprecedented accuracy.

The Vera Astrometry Catalog was published in the Publications of the Astronomical Society of Japan.

 



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Spacecraft With Precious Asteroid Cargo Is Almost Home After 5-Billion Km Trek

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In the dusty desert town of Woomera, in the South Australian desert, scientists are getting ready. On 6 December 2020, after six years in space, the Japan Aerospace Exploration Agency’s Hayabusa2 spacecraft will finally return to Earth.

 

It carries with it a cargo unbelievably rare, precious, and hard-won – at least 100 milligrams of material collected from the surface of asteroid Ryugu. It will drop the capsule containing the sample to Earth, the spacecraft itself continuing on to visit more asteroid targets.

Hayabusa2’s return will mark a milestone in a remarkable feat of space science, a total journey of around 5.24 billion kilometres (almost 3.3 billion miles). Asteroid Ryugu – formerly known as 1999 JU3 – is on an elliptical orbit that carries it just inside Earth’s orbital path around the Sun, and out almost as far as Mars‘ orbit.

Planning Hayabusa2’s trip involved calculating where the asteroid would be in the future, and plotting a path that would get the spacecraft where it needed to go, using Earth’s gravity for bursts of acceleration.

Then, the spacecraft had to be able to touch down on the asteroid, twice, collect material both times, and bounce back off the asteroid again, before making its way back to where Earth would be by the time its journey back was over.

 

The spacecraft is on that home stretch now, and the capsule collection team have all arrived in Australia. Capsule retrieval rehearsals and tests of the technology that will be used to track the incoming capsule are being conducted.

Preliminary team members who have already cleared their two-week COVID-19 quarantine arrived at the Woomera Royal Australian Air Force base last week, and started preparations for the landing and retrieval.

That tiny cargo is a big deal. Only one other mission has successfully returned an asteroid sample. JAXA’s original Hayabusa mission to asteroid Itokawa returned a sample to Earth in 2010 – but the sampling device had failed, and only a few micrograms of material were ferried home.

One hundred milligrams is an absolute wealth of material in comparison, and scientists hope to be able to conduct detailed tests. Because Ryugu is a primitive carbonaceous asteroid, it’s thought that it has preserved some of the most pristine material in the Solar System, relatively unchanged (except for some irradiation) since it formed around 4.5 billion years ago.

That small sample, scientists hope, will be able to provide some insight into the early days of the Solar System, and the formation and evolution of the inner rocky planets.

The capsule is expected to descend between 3.30 AM and 4.30 AM ACDT (Australian Central Daylight Time) on 6 December 2020, creating a brilliant fireball produced by the heat of atmospheric entry. A special heat shield will protect the capsule from temperatures around 3,000 degrees Celsius (5,400 degrees Fahrenheit).

After deploying its parachute, it is expected to land within a 100 square kilometre- (40 square mile-) region within the Woomera Protected Area, sending out a radio signal to the retrieval team. Once the beacon lands, this signal won’t be detectable from ground stations, so a helicopter will be flown overhead to track the capsule down.

Once it’s located, the capsule will be taken by helicopter to a Quick Look Facility. There, any gases inside the container will be sampled, before the container is placed in a sealed transport box and airlifted back to Japan. That’s when the next stage of the research process will truly begin, as scientists start the painstaking work of studying and analysing the rock.

Although most of the world won’t be able to watch the reentry live, JAXA has issued observing and photography tips for those who can, and, for everyone, an AR app for iOS to track the capsule’s trajectory. JAXA is also considering a livestream of the capsule release and atmospheric entry.

Meanwhile, Hayabusa2’s flight will continue. Its next stop will be asteroid (98943) 2001 CC21 in July 2026, after which it will continue on to asteroid 1998 KY26 for a July 2031 rendezvous.

 



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