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China Launches ‘Audacious’ Mission to Obtain First New Lunar Samples in Decades

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For decades, planetary geologists have studied tiny chunks of lunar rock to unravel the Moon’s mysteries. The rocks have revealed how old the Moon is, helped scientists estimate the age of other planets, and offered insight into how turbulent our Solar System once was.

 

But nobody has collected any new Moon rocks for more than 40 years.

China’s National Space Administration is poised to change that. On Monday afternoon at 3:31 pm ET (4:31 am Tuesday local time), China launched a spacecraft toward the Moon.

The mission, called Chang’e-5, aims to land a robot on the lunar surface to collect samples for the first time in China’s history. A spacecraft will then return to Earth with the samples.

The mission is the sixth in a series of ambitious steps by the China to explore the Moon, which could potentially lead to the building of a human settlement there.

“This is a really audacious mission,” David S. Draper, the deputy chief scientist at NASA, told the New York Times.

“They’re going to move the ball down the field in a big way with respect to understanding a lot of things that are important about lunar history.”

The Chang’e-5 spacecraft aims to collect 4 pounds (1.8 kg) of Moon rock and dust from a previously unexplored region: a volcanic plain called Mons Rümker. The material could provide new information about the Moon’s past volcanic activity.

A successful mission would make China the third nation to bring Moon-rock samples back to Earth, after the US and the Soviet Union.

 

A tricky mission

Chang’e-5 lifted off from China’s Wenchang Satellite Launch Centre on Hainan Island. It is expected to enter the Moon’s orbit within a week, though the Chinese government has not provided a detailed timeline.

After that, it should split into two parts: an orbiter and a descender. The orbiter, as its name suggests, is designed to remain in orbit. The descender – which is itself comprised of an ascender and a lander – is programmed to land near the Moon’s Mons Rümker plain.

Assuming the landing is successful, the lander will then have just one lunar day – the equivalent of 14 Earth days – to collect the lunar samples. It can’t stick around during the Moon’s harsh night-time because extremely cold conditions could damage the spacecraft’s electronics.

The robot is slated to drill more than 6 feet (1.8 metres) into the ground. After collecting the samples, the lander should transfer them to the ascender vehicle. That spacecraft is then expected to blast off from the Moon’s surface – the first time China has ever launched a vehicle from another planetary body – and re-enter the Moon’s orbit.

 

Once there, it’s expected to dock with the orbiter and transfer the sample into the orbiter’s return capsule.

After the delicate, multi-step manoeuvre is complete, the orbiter is slated to remain in orbit for six days before beginning its journey back to Earth. The capsule is expected to parachute down into Inner Mongolia around mid-December.

The youngest region of the Moon ever explored

Previous Moon-rock samples collected by the US and Soviet Union have led scientists to conclude that volcanoes were active on the lunar surface about 3 billion years ago. But scientists estimate that regions like the Mons Rümker plain may have hosted volcanic activity as recently as 1.2 billion years ago, based on observations of the lunar surface.

If lunar volcanoes were indeed active that recently, “we will rewrite the history of the Moon,” Xiao Long, a planetary geologist at the China University of Geosciences in Wuhan, told Nature.

Analysing lunar rocks could help planetary scientists understand how the Moon was able to sustain volcanic activity for billions of years.

“The Moon is small, so its heat engine should have run out a long time ago,” Clive Neal, a geoscientist at the University of Notre Dame in Indiana, told Nature.

 

The rocks could also help scientists determine the age of regions on other planets, like Mars. Researchers investigate this by analysing the ages of Moon-rock samples, then counting the craters on the areas of the Moon those samples came from.

More craters on a region’s surface indicates that it’s older, since there has been more time for impacts to accumulate, and the early Solar System was more violent than the present.

Scientists then can estimate how old other planets’ regions are by comparing how many craters their surfaces have relative to the Moon.

So far, scientists have only been able to study Moon-rock samples from lunar regions that are 3 billion years old or more.

Because the Mons Rümker plain appears to be far younger, samples from the region could help scientists more precisely estimate the region’s age, and consequently the ages of younger regions on other planets, too.

This article was originally published by Business Insider.

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Asteroid Apophis Has a Slim Chance of Hitting Us in 2068. Scientists Are Making Plans

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It’s comforting to imagine that with both space- and Earth-based telescopes trained on the cosmos, we’d be able to spot any hazardously sized asteroids heading our way a mile off, with plenty of time to paint them white or explode them away.

 

But for every asteroid we see coming in our direction, there’s a number we miss until they fly on by.

And even for those we know about well in advance, it can still be hard to nail down just how likely an Earth collision actually is.

Asteroid 99942 Apophis is one of these asteroids, whose orbit can pass a little too close to Earth for comfort.

Discovered in 2004, the 370-metre (1,210-foot) long rocky blob is on NASAs Sentry list – a list of asteroids we should be keeping an eye on – and although scientists have crossed off any chance of it hitting during its next close flyby in 2029, they’re not so sure it won’t slam into us in 2068 as it comes this way again.

While the risk of Apophis hitting Earth in 2068 is somewhere in the region of 1 in 150,000, an asteroid that size would cause a blast larger than an atomic bomb, so it’s best to double check the numbers.

And a presentation at the American Astronomical Society’s Division for Planetary Sciences virtual conference is probably not going to make you sleep better at night.

 

Late last month, astronomer David Tholen from the University of Hawaii presented his and his colleague Davide Farnocchia’s research after observing the asteroid for three nights in January and one night in March.

They were able to get incredibly precise information about the asteroid, and were able to detect Yarkovsky acceleration – meaning that the asteroid radiates heat more strongly on its Sun facing hemisphere than its shadow side, which causes an asymmetrical push, slightly changing its orbit.

When you work that acceleration into the asteroid’s model, “that basically means that the 2068 impact scenario is still in play,” explains Tholen in his presentation.  

“We need to track this asteroid very carefully – obviously the 2029 close approach is critical.”

The April 2029 close approach is going to be very close (closer than some of our communication satellites close) and it gives scientists a very important opportunity to study Apophis in exceptionally high detail.

And with less than nine years to go, earlier this month the Lunar and Planetary Institute held a virtual workshop to try and get that ball rolling.  

 

“Knowledge is the first line of planetary defence, and the 2029 Apophis encounter is a once-per-thousand-year opportunity,” the Lunar and Planetary Institute states.

“We have less than a decade to plan Earth-based and possible in-situ missions whose measurements can deliver unprecedented detailed knowledge on the physical nature of Apophis as the prototype example (poster child) of potentially hazardous asteroids.”

If we’re lucky, we might get a Bennu style mission to Apophis to explore the asteroid with a spacecraft, finding out information that telescopes alone can’t hope to show us.

This asteroid “presents an excellent opportunity to prototype and demonstrate a rapid response Near Earth Orbit reconnaissance capability,” Brent Barbee, an aerospace engineer from the University of Maryland explained at the conference, according to Gizmodo.

While George Dvorsky at Gizmodo outlines some of the possibilities, we’re still yet to iron out what sort of scientific welcome mat we’re going to give Apophis.

Whether it’s a new spacecraft, a quick detour for OSIRIS-Rex, or purely ground based observations, we’re about to learn a lot about our uncomfortably close neighbour – and hopefully we can confirm once and for all if Apophis is crashing at our place in 2068. Then, we can work out what to do next.

 



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Ancient Meteorite Hints Mars Had Water Before There Was Life on Earth

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We know that Mars was once much wetter than it is now, but the questions of when water formed and evaporated away are much more difficult to answer.

A new study now suggests that water was present on the Red Planet some 4.4 billion years ago, much earlier than previously thought.

 

That’s based on an analysis of a meteorite named NWA 7533, picked up in the Sahara Desert and thought to have originated on Mars billions of years ago. The oxidation of certain minerals inside the meteorite hints at the presence of water.

The findings could push back the estimated date of water formation on Mars some 700 million years, from the 3.7-billion-years-ago timeframe that has been the general consensus up until now. The research could also offer up some insights into how planets form in the first place.

“I study minerals in Martian meteorites to understand how Mars formed and its crust and mantle evolved,” says planetary scientist Takashi Mikouchi from the University of Tokyo in Japan.

“This is the first time I have investigated this particular meteorite, nicknamed ‘Black Beauty’ for its dark colour. Our samples of NWA 7533 were subjected to four different kinds of spectroscopic analysis, ways of detecting chemical fingerprints. The results led our team to draw some exciting conclusions.”

Planetary scientists are keenly interested in the story of water on planets and on moons. One of the big unknowns is whether water gets added to a planetary body after it forms, through the impacts of asteroids and comets, or whether it occurs naturally during the planet formation process.

 

Ancient rocks like NWA 7533 can help scientists peer back in time and find out, as they record impact events on the planet they come from, and capture some of the mineral and chemical composition of the surface when they are formed.

In this case, it’s the oxidation that’s the tell-tale sign of water. With certain fragments inside NWA 7533 dated to 4.4 billion years ago, it’s the oldest record we’ve got of Mars (which may be why a single gram of this meteorite can fetch as much as US$10,000).

“Igneous clasts, or fragmented rock, in the meteorite are formed from magma and are commonly caused by impacts and oxidation,” says Mikouchi. “This oxidation could have occurred if there was water present on or in the Martian crust 4.4 billion years ago during an impact that melted part of the crust.”

Such an early appearance suggests that water actually was around when Mars formed and that in turn plays into research into planetary formation in general. With water comes life, which is one reason scientists are so eager to track it down around the Universe. For comparison, we know that the earliest traces of life on Earth date to at least 3.5 billion years ago.

The close study of Mars continues as experts try and figure out when water was present and what form it might have taken. One recent study put forward the idea that both liquid water and surface ice could have existed on the Red Planet at the same time.

The team’s findings also suggest that the chemical make-up of the Martian atmosphere at this time – including high levels of hydrogen – could have made the planet warm enough for water to melt and life to exist, even though the Sun would have been younger and fainter during this period.

“Our analysis also suggests such an impact would have released a lot of hydrogen, which would have contributed to planetary warming at a time when Mars already had a thick insulating atmosphere of carbon dioxide,” says Mikouchi.

The research has been published in Science Advances.

 



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The BepiColombo Probe Just Took a Ridiculously Close Video of Venus as It Flew By

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Two years after it left Earth, Mercury probe BepiColombo has completed the first of its first flybys of Venus. The manoeuvre is designed to give the spacecraft a boost on its journey – but it’s also too good an opportunity to pass up for a little science.

 

As it swung around the planet on a curved trajectory, BepiColombo gave its instruments a workout, testing their functionality for a taste of what the spacecraft will do in Mercury orbit and collecting some data on Venus – recently in the news for the discovery of phosphine gas in its atmosphere.

And the joint European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) probe took a whole lot of images, which the ESA compiled into a video of the flyby.

“This sequence of 64 images was captured by Monitoring Camera 2 onboard the Mercury Transfer Module from 40 minutes before until 15 minutes after closest approach of 10,720 kilometres (6,661 miles) from Venus,” wrote the ESA in a blog post. “The images were taken every 52 seconds.”

The images had to be slightly processed – Venus was so bright that the images are quite saturated, even with the shortest exposure times. But the shape of the terminator line, which marks the boundary between night and day, changes as BepiColombo moves around the planet in a curved trajectory.

venus flyby body 700(ESA/BepiColombo/MTM)

Gravity assist manoeuvres are a very common tool for moving spacecraft around the Solar System. They’re also the work of very careful planning, with a route painstakingly mapped out in advance, with forward projection of where planets and moons are going to be when the spacecraft reaches them, in order to make the most of the encounters a voyaging spacecraft is going to have.

Basically, gravity assists use the gravity of a planet to aid the spacecraft in its journey, altering its trajectory and speed – either giving it a slingshot forwards, or helping it slow down. BepiColombo’s journey involves nine gravity assists. The first involved Earth on April 10, earlier this year.

Venus was the second, taking place on October 15, using the planet’s gravity to slow the spacecraft down without expending fuel. The third will also be Venus, in August 2021; the remaining six gravity assist flybys will be of Mercury itself, further slowing BepiColombo down so that it can finally arrive in a stable orbit in December 2025.

Both Venus flybys will be used to test BepiColombo instruments and collect Venus data. In this first flyby, scientists with the German Aerospace Center (DLR) and the University of Münster in Germany fired up the MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS) instrument to take almost 100,000 images as BepiColombo approached the planet.

“During the Earth flyby, we studied the Moon, characterising MERTIS in flight for the first time under real experimental conditions. We achieved good results,” said MERTIS project manager Gisbert Peter of the DLR Institute of Optical Sensor Systems.

 

“Now we are pointing MERTIS towards a planet for the first time. This will allow us to make comparisons with measurements taken prior to the launch of BepiColombo, to optimise operation and data processing, and to gain experience for the design of future experiments.”

Venus and Mercury are quite different from one another – Mercury’s a naked ball of dense rock and metal, and Venus is shrouded in a thick, toxic atmosphere that keeps the planet’s surface temperature at scorching levels. MERTIS was designed to collect data on the rock composition of Venus, but its infrared capabilities can also penetrate Venus’ clouds to a certain depth.

MERTIS won’t be able to detect the phosphine that so intrigued the world. But one theory about the phosphine was that it was created by volcanic activity. And recent evidence suggests that volcanic activity may be ongoing on Venus; this is something MERTIS can investigate.

“These [volcanoes] would be detected, for example, through the sulphur dioxide that they emit,” said planetary scientist Jörn Helbert from the DLR Institute of Planetary Research.

 

“Following the first measurements made in the 1960s and 1970s, about ten years ago, ESA’s Venus Express mission recorded a massive reduction, by more than half, of sulphur dioxide concentrations. Venus literally ‘smells’ of active volcanoes! MERTIS could now provide us with new information.”

We won’t have that information for a little while yet. The newly collected data will have to make its way down the processing and analysis pipeline. But it’s so exciting, being on the cusp of a new era of Solar System science. And, although it’s not BepiColombo’s main mission, it’s really exciting having a different, newer set of tools to poke into Venus’ mysteries.

“We are already expecting some very interesting findings, with more to follow in 2021, when we will be much closer to Venus,” said planetary scientist Harald Hiesinger of the University of Münster.

 



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Astronomers Just Revealed One of The Most Extreme Planets Ever Discovered

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Astronomers have taken detailed observations of an incredibly extreme exoplanet, detecting brutal surface temperatures in the region of 3,200 degrees Celsius (5,792 degrees Fahrenheit).

 

Those temperatures – measured by the European Space Agency’s CHaracterising ExOPlanet Satellite (or CHEOPS) –  are enough to melt all rocks and metals, and even turn them into a gaseous form.

While the exoplanet, named WASP-189b, is not quite as hot as the surface of our Sun (6,000 degrees Celsius or 10,832 degrees Fahrenheit), it’s basically as toasty as some small dwarf stars.

The new findings immediately identify WASP-189b as one of the most extreme planets ever discovered. It has an orbit of just 2.7 days around its star, with one side seeing a permanent ‘day’ and the other side seeing a permanent ‘night’. It’s gigantic, too – about 1.6 times the size of Jupiter.

wasp 189b 2(ESA)

“WASP-189b is especially interesting because it is a gas giant that orbits very close to its host star,” says astrophysicist Monika Lendl from the University of Geneva in Switzerland. “It takes less than three days for it to circle its star, and it is 20 times closer to it than Earth is to the Sun.”

HD 133112 is the host star in question, 2,000 degrees Celsius (3,600 degrees Fahrenheit) hotter than our Sun, and one of the hottest stars known to have a planetary system around it. CHEOPS made an interesting discovery about this celestial body too: it’s spinning so fast that it’s being pulled outwards at its equator.

 

WASP-189b is too far away (326 light-years) and too close to HD 133112 to observe directly, but CHEOPS knows some tricks. First, it observed the exoplanet as it passed behind its star: an occultation. Then, it watched as WASP-189b passed in front of its star: a transit.

From these readings, researchers were able to figure out the brightness, temperature, size, shape, and orbital characteristics of the exoplanet, as well as some extra information about the star that it’s circling around.

As it’s on the scale of Jupiter but much closer to its host star, and much hotter, WASP-189b qualifies as a so-called hot Jupiter planet (you can see where the name came from). Scientists are hoping that the information CHEOPS has gathered about WASP-189b will improve our understanding of hot Jupiters in general.

“Only a handful of planets are known to exist around stars this hot, and this system is by far the brightest,” says Lendl. “WASP-189b is also the brightest hot Jupiter that we can observe as it passes in front of or behind its star, making the whole system really intriguing.”

One of the questions that the new CHEOPS research has raised is how WASP-189b was formed in the first place – its inclined orbit suggests it formed further out from HD 133112 and was then driven inwards.

Besides the treasure trove of data this new study has provided, it also shows CHEOPS working as intended and working well, measuring brightness across deep space with a mind-boggling level of accuracy.

The satellite has plenty more missions to move on to next, with hundreds of exoplanets in the queue for closer observation. The data that it collects should teach us more about our own Solar System, as well as the planets outside of it.

“The accuracy achieved with CHEOPS is fantastic,” says planetary scientist Heike Rauer from the DLR Institute of Planetary Research in Germany. “The initial measurements already show that the instrument works better than expected. It is allowing us to learn more about these distant planets.”

The research has been published in Astronomy & Astrophysics.

 



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We Now Know How Dying Stars Carve Out Mesmerising Mandalas of Stardust

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The last gasps of dying stars are some of the most beautiful objects in the galaxy.

They’re called planetary nebulae, clouds of stellar material ejected out into space as a red giant star enters the last stage of its life. The dying star shucks off its outer layers, which are illuminated from within by the hot, exposed core.

 

These clouds are complex, and gorgeous, with mandala-like waves, strange discs, even bilobed jets akin to wings. The stunning complexity and variety of these shapes seems at odds with the uniform shape of their precursor stars.

“The Sun – which will ultimately become a red giant – is as round as a billiard ball, so we wondered: how can such a star produce all these different shapes?” said astronomer Leen Decin of KU Leuven in Belgium.

Now, through a detailed collection of observations and hydrodynamical simulations, scientists have discovered how planetary nebulae might get their shapes: through gravitational interactions with binary star companions, and large planets like Jupiter that survive the violent deaths of their host stars.

Initially, the team wasn’t looking at planetary nebulae at all. The focus of their studies was a slightly earlier life stage called the asymptotic giant branch (AGB).

This is when the red giant is in the last stages of evolution before the planetary nebula phase, and powerful winds from the star are blowing out into the space around it, scattering gas and dust.

 

Red giants are the old age of a particular kind of star, less than about eight times the mass of the Sun. It’s how the Sun is going to end its life, puffing up to engulf Mercury, Venus and maybe even Earth, before its core collapses into a tiny white dwarf gleaming brightly with residual heat.

So, how these stars die is very interesting to astronomers. And yet Decin’s international team found that a detailed database of observational data on the winds of AGB stars has not been compiled. So they set about creating one.

“The lack of such detailed observational data caused us to initially assume that the stellar winds have an overall spherical geometry, much like the stars they surround,” said astronomer Carl Gottlieb of the Harvard-Smithsonian Center for Astrophysics.

“Our new observational data shapes a much different story of individual stars, how they live, and how they die. We now have an unprecedented view of how stars like our Sun will evolve during the last stages of their evolution.”

star winds(L. Decin, ESO/ALMA)

Using the Atacama Large Millimeter/submillimeter Array in Chile, the team took observations of a sample of AGB stars. In those data, they noticed a range of structures – including arcs, shells, bipolar structures, clumps, spirals, doughnut shapes, and rotating discs.

Since the radially outflowing winds were smooth, the team quickly ascertained that something in the immediate vicinity of the star could be causing the structures in the material – like a small binary companion or giant planet, too faint to be seen, but whose gravitational tugging could be affecting the material.

 

Sure enough, when they modelled the effect of a companion on these outflows, the team found that each type of structure they observed could be created by the presence of a secondary object. The mass of that object, its distance from the star, and the eccentricity of its orbit can all play a role in the variety of the structures produced in the stellar wind.

“Just like a spoon that you stir in a cup of coffee with some milk can create a spiral pattern, the companion sucks material towards it as it revolves around the star and shapes the stellar wind,” Decin said.

“All of our observations can be explained by the fact that the stars have a companion.”

All the shapes bore strong similarities to the complex structures and shapes seen in planetary nebulae, suggesting the structures in the two stages have the same formation mechanism. And there are wide-ranging implications for our understanding of stellar evolution.

“Our findings change a lot,” Decin said. “Since the complexity of stellar winds was not accounted for in the past, any previous mass-loss rate estimate of old stars could be wrong by up to a factor of 10.”

 

The discovery also strongly hints at what might happen when the Sun dies. Our Sun, of course, does not have a binary companion (which is also a bit of a mystery in its own right).

But the Solar System does have two planets massive enough to potentially influence its outflows. Those are Jupiter and Saturn, the gas giants, whose mass is already large enough to tug the Sun around in a tiny wobbly circle.

They’ll be far beyond the Sun’s reach when our star becomes a red giant, and recent discoveries suggest that giant planets can indeed survive their stars’ deaths – maybe not for long, but long enough to make some waves (or arcs or shells).

The team’s calculations predict that Jupiter, and maybe Saturn, will be able to carve some relatively weak spirals in the Sun’s AGB wind.

The team is now conducting further research to find out what else their discovery might change for our understanding of the deaths of stars.

The research has been published in Science.

 



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New Research Is Rewriting The Very Timeline of How Earth Was Born

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In the very early days of the Solar System, baby Earth may have taken a much shorter time to form than we previously thought.

According to an analysis in February 2020, there’s evidence that most of Earth took just 5 million years to come together – several times shorter than current models suggest.

 

This revision is a significant contribution to our current understanding of planetary formation, suggesting that the mechanisms may be more varied than we think, even between planets of the same type, located in the same neighbourhood – rocky planets, such as Mars and Earth.

You see, we’re not really 100 percent sure about how planets form. Astronomers have a pretty good general idea, but the finer details … well, they’re rather hard to observe in action.

The broad strokes of planetary formation process are bound up in stellar formation itself. Stars form when a clump in a cloud of dust and gas collapses in on itself under its own gravity, and starts spinning. This causes the surrounding dust and gas to start swirling around it, like water swirling around a drain.

As it swirls, all that material forms a flat disc, feeding into the growing star. But not all the disc will get slurped up – what remains is called the protoplanetary disc, and it goes on to form the planets; that’s why all the Solar System planets are roughly aligned on a flat plane around the Sun.

 

When it comes to planetary formation, it’s thought that tiny bits of dust and rock in the disc will start to electrostatically cling together. Then, as they grow in size, so too does their gravitational strength. They start to attract other clumps, through chance interactions and collisions, gaining in size until they’re a whole dang planet.

For Earth, this process was thought to have taken tens of millions of years. But an analysis of the iron isotopes found in Earth’s mantle suggest otherwise, according to scientists from the University of Copenhagen in Denmark.

In its composition, Earth appears to be unlike other Solar System bodies. Earth, the Moon, Mars, meteorites – all contain naturally occurring isotopes of iron, such as Fe-56 and the lighter Fe-54. But the Moon, Mars and most meteorites all have similar abundances, while Earth has significantly less Fe-54.

The only other rock that has a similar composition to Earth’s is a rare type of meteorite called CI chondrites. The interesting thing about these meteorites is that they have a similar composition to the Solar System as a whole.

 

Imagine if you were to get all the ingredients for a bolognese. Mix them all together in one big pot – that’s the protoplanetary disc, and later the Solar System. But if you scattered your ingredients into a bunch of smaller pots, with different proportions of each ingredient – now you have the individual planets and asteroids.

What makes CI chondrites special is that in this analogy, they are like teeny tiny pots containing the initial proportions of ingredients for a full bolognese. So, having one of these space rocks on hand is like having a microcosm of the dust that swirled around in the protoplanetary disc at the dawn of the Solar System, 4.6 billion years ago.

According to current planetary formation models, if things just smooshed together, the iron abundances in Earth’s mantle would be representative of a mix of all different kinds of meteorites, with higher abundances of Fe-54.

The fact that our planet’s composition is only comparable to CI dust suggests a different formation model. Instead of rocks banging together, the researchers believe that Earth’s iron core formed early through a rain of cosmic dust – a faster process than the accretion of larger rocks. During this time, the iron core formed, slurping up the early iron.

Then, as the Solar System cooled, after its first few hundred thousand years, CI dust from farther out was able to migrate inwards, to where Earth was forming. It sprinkled all over Earth, basically overwriting whatever iron was in the mantle.

Because the protoplanetary disc – and the large abundances of CI dust in it that could have rained down on Earth –  only lasted about 5 million years, Earth must have accreted within this timeframe, the researchers conclude.

“This added CI dust overprinted the iron composition in the Earth’s mantle, which is only possible if most of the previous iron was already removed into the core,” explained planetary geologist Martin Schiller of the University of Copenhagen.

“That is why the core formation must have happened early.”

If this “cosmic dust” accretion model is how Earth formed, this research also means that other planets elsewhere in the Universe could have formed this way.

This not only broadens our understanding of planetary formation, but it could have implications for our understanding of life within the Universe. It could be that this kind of planetary formation is a prerequisite for the conditions conducive to life.

“Now we know that planet formation happens everywhere. That we have generic mechanisms that work and make planetary systems. When we understand these mechanisms in our own solar system, we might make similar inferences about other planetary systems in the galaxy. Including at which point and how often water is accreted,” said cosmochemist Martin Bizzarro of the University of Copenhagen.

“If the theory of early planetary accretion really is correct, water is likely just a by-product of the formation of a planet like Earth – making the ingredients of life, as we know it, more likely to be found elsewhere in the Universe.”

The research was published in Science Advances.

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

 



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Don’t Miss This Increasingly Rare Chance to See a Comet With The Naked Eye

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Neowise is the first bright comet to be visible with the naked eye from the Northern Hemisphere since the mid-1990s.

Another thing that makes this comet interesting is that it has a relatively long orbital period, meaning it was only discovered a few months ago.

 

Halley’s comet, for example, takes about 75 years to return to the same position near Earth, meaning everybody has the opportunity to see it potentially twice during their lifetime.

Neowise has an orbit of almost 6,800 years, meaning that the last generation of people to see it would have lived during the fifth millennium BCE.

This was a time well before the written word, when the global human population was about 40 million people.

The cause of this really long return time is the elliptical shape of Neowise’s orbit around the Sun.

In the early 17th century, astronomer Johannes Kepler derived his laws of planetary motion, which apply to any object orbiting in space, including comets. 

These laws state that objects on highly elliptical orbits will move fast near the barycenter – the centre of mass of two or more bodies that orbit one another – of the path and much slower further away.

So comet Neowise will only be seen for a few weeks near Earth while it is near perihelion (its closest approach to the Sun).

It will then spend thousands of years moving slowly near the other end of its orbit. It’s aphelion (farthest point) is estimated at 630 astronomical units (AU), with one AU being the distance between the Earth and the Sun.

 

To put that in perspective, the Voyager 1 spacecraft is the farthest human crafted object from Earth and it is currently at a mere 150 AU.

The dwarf planet Pluto also has an elliptical orbit, which ranges from just 30 AU at perihelion to 49 AU at aphelion.

Comets often have two tails, and comet Neowise is no exception. One is made of electrically neutral material such as water ice and dust particles forming the distinct white fuzzy shape around the comet and its tail. As the Sun heats up the comet, these tiny particles are released and create a shining tail behind it.

The second tail is made from a plasma – an electrically charged cloud of gas. This shines by fluorescence, the same process that causes aurora on Earth, and is used in neon lighting.

Colours can be green or blue depending on the kind of charged gas escaping from the comet. As the plasma flows away from the comet it is guided by the Sun’s magnetic field and the solar wind.

This causes separation between the two tails – one being driven by the comet’s direction, and the other by the Sun’s magnetic field.

 

How to spot Neowise

Even though Neowise is very distant from Earth, with its closest approach on July 22 being almost as far away as Mars, it is still visible in the night sky to the naked eye – hovering near the northern horizon.

The comet is estimated to currently be at magnitude 1.4 – a measure of brightness astronomers use, with smaller numbers denoting brighter objects. Venus, which is the brightest planetary object in the sky, is about -4. Comet Hale-Bopp reached a maximum magnitude of 0 in 1997 due to its exceptionally large size, while comet McNaught was visible from the Southern Hemisphere with a maximum magnitude of -5.5.

Neowise may get brighter over the next week, but which level of brightness it reaches will depend primarily on how much material erupts from its surface rather than the distance from the Earth.

This material consists of highly reflective water ice particles from the nucleus of the comet erupting outwards, shining when they catch the sunlight.

Comet Halley on the Bayeux Tapestry. (Wikipedia/CC BY-SA)Comet Halley on the Bayeux Tapestry. (Wikipedia/CC BY-SA)

Rich history

The history of cometary observations is extensive, making vital contributions to the development of modern astronomy, and has had quite an impact on human history.

Halley’s comet, for example, was famously featured on the Bayeux Tapestry (above) as it made an appearance in the months leading up to the Norman conquest of England in 1066 (magnitude estimated at about 1).

 

In the late medieval period, comets helped astronomers to fundamentally refine their understanding of the Solar System. An essential component of the then standard Ptolemaic geocentric model of the Solar System, which dominated astronomy for 15 centuries, mandated that the planets were fixed to a series of concentric transparent celestial spheres, with the Earth at the centre.

Even after the Copernican revolution, which put the Sun at the centre of the Solar System, the celestial spheres were retained as a concept. However, in the late 1500s several astronomers, including Tycho Brahe, noted that comets with their highly elliptical orbits seemed to pass through these spheres without hindrance.

These observations contributed to the eventual abandonment of the Ptolemaic system entirely, and the subsequent explanation of planetary orbits by Johannes Kepler, which is still in use today.

Important observations during the space age include the first close encounter between a comet and spacecraft. Halley’s comet was imaged from a distance of just a few hundred kilometres by the Giotto spacecraft. And in 2014 the Rosetta spacecraft became the first to orbit a comet, and deploy a lander on the surface, sending back remarkable images to Earth.

The sobering role of comets in shaping planetary evolution was also demonstrated spectacularly in 1994 when comet Shoemaker-Levy-9 collided with Jupiter.

Comet crashing with Jupiter. (Max Planck Insititute)Comet crashing with Jupiter. (Max Planck Insititute)

With the constant increase of light pollution in the night sky, the observation of comets with the naked eye is becoming much rarer.

For now, though, Neowise presents a fantastic opportunity for millions of people to see a night sky phenomenon which typically only presents itself perhaps once in a decade or more. Enjoy the view!The Conversation

Gareth Dorrian, Post Doctoral Research Fellow in Space Science, University of Birmingham and Ian Whittaker, Senior Lecturer in Physics, Nottingham Trent University.

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

 



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Earth Germs Probably Can’t Contaminate The Briny Waters on The Surface of Mars

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When we found what seemed to be liquid water flowing across the surface of Mars in 2015, scientists around the world were itching to test it. There was just one problem, and it was a biggie: the United Nations’ Outer Space Treaty of 1967 mandates that space exploration must be conducted in such a way as to avoid contamination.

 

Since we have no way of sterilising our equipment completely of Earth’s microbes, that meant no touchy on the water.

According to new research, however, we needn’t have worried – although there could be briny liquid water on Mars, the surface conditions otherwise really are inhospitable to terrestrial life.

“Life on Earth, even extreme life, has certain environmental limits that it can withstand,” explained planetary scientist Edgard G. Rivera-Valentín of the Universities Space Research Association (USRA) and the Lunar and Planetary Institute (LPI).

“We investigated the distribution and chemistry of stable liquids on Mars to understand whether these environments would be suitable to at least extreme life on Earth.”

While seeking to understand how life might exist elsewhere, we often look at extremophiles – organisms that live in some of Earth’s most extreme environments. These include the arid Atacama Desert in Chile, the salty, acidic Dallol Geothermal Area in Ethiopia, and even near-Earth space aboard the ISS.

But while these environments have things in common with Mars, they are distinctly not Mars. Liquid water seems to be a requirement for life, but on Mars, liquid fresh water can’t hang around on the surface. It’s so dry and cold there, the water will either freeze or evaporate.

 

Of course, water doesn’t have to be fresh to support life. Earth’s salty oceans are teeming with it. And we know that salts of sodium, magnesium, and calcium are abundant on Mars; if these salts mixed with the water to create a high-salt solution called brine, it would lower the freezing point and slow the evaporation rate of the liquid, potentially allowing it to linger on the surface.

And if there was enough moisture in the Martian atmosphere, some of the salts could undergo a process called deliquescence, whereby they absorb the moisture to form a liquid solution.

But questions remain: Can this liquid brine form and remain on the Martian surface long enough for terrestrial life to thrive? 

“Our team looked at specific regions on Mars – areas where liquid water temperature and accessibility limits could possibly allow known terrestrial organisms to replicate – to understand if they could be habitable,” said planetary scientist Alejandro Soto of the Southwest Research Institute.

“We used Martian climate information from both atmospheric models and spacecraft measurements. We developed a model to predict where, when and for how long brines are stable on the surface and shallow subsurface of Mars.”

 

Based on years of experimental data on chemical reactions in simulated Mars conditions in the laboratory, as well as the climate data, the team put together a picture of when and where liquid brines might be present on the surface of Mars, and a few centimetres below.

They found that liquid brines could persist for up to six hours from the equator to high latitudes, over 40 percent of the Martian surface. And this could only occur seasonally, for around 2 percent of the year.

It may not sound like a lot, but it’s a broader range than scientists previously thought. But that still doesn’t mean Earth’s life could survive in it.

“The highest temperature a stable brine will experience on Mars is -48 degrees Celsius (-55 degrees Fahrenheit),” Rivera-Valentín said. “This is well below the lowest temperature we know life can tolerate.”

This means, the team concluded, that Martian brines don’t meet the Special Region requirements laid out by the Committee on Space Research (COSPAR) of the International Council for Science, and should therefore prove no hindrance to a crewed Mars exploration mission.

It’s also important to note that these results don’t have any bearing on native Martian life, if there is or was any throughout the planet’s history – they’re based entirely on our understanding of terrestrial life. And that could be a limitation, too.

“We have shown that on a planetary scale the Martian surface and shallow subsurface would not be suitable for terrestrial organisms because liquids can only form at rare times, and even then, they form under harsh conditions,” Rivera-Valentín said.

“However, there might be unexplored life on Earth that would be happy under these conditions.”

The research has been published in Nature Astronomy.

 



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We Just Got Incredible New Photos of Our Lonely Little World From LightSail 2

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Ten months in space!

The Planetary Society’s LightSail 2 spacecraft just reached that milestone. And the fine folks at the Society have released a bunch of new pictures from the spacecraft.

 

Ten of them, in fact. One for each successful month.

LightSail 2 is a technology demonstration mission for the most part. And it’s been successful so far. In January 2020, the Planetary Society released a paper outlining the mission results. In brief, LightSail 2’s solar sails are working, though the spacecraft is still expected to fall to Earth within a year of launch.

The spacecraft carries cameras, of course. Those cameras are there primarily to check on the solar sails. But while doing that, they’re capturing some delicious photos of Earth in the background.

Note: the camera has a fish-eye lens, making the sail appear a little curved in the pictures.

North is to the right, with Chile in view. (The Planetary Society)North is to the right, with Chile in view. (The Planetary Society)

The next one is a little disorienting. North is at the bottom of the image, and it shows shows Central America, including Nicaragua and the Yucatan Peninsula, home of the dinosaur killing asteroid crater.

(The Planetary Society)(The Planetary Society)

The Planetary Society has a Mission Control page where you can check out the status of LightSail 2.

If you’re not familiar with The Planetary Society, definitely check them out. They’re a non-profit society dedicated to promoting space science and exploration. And Bill Nye is their CEO.

Other images show the deployment of the sail itself.

(The Planetary Society)(The Planetary Society)

These high-resolution images were captured by LightSail 2’s camera 2 during sail deployment on 23 July 2019. The sail appears slightly curved due to the spacecraft’s 185-degree fisheye camera lens; no corrections have been made to the pictures.

If you’re interested, you can visit their website and get involved. You can get updates from the Society, and even become a member.

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

 



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