Connect with us

Space

Oumuamua First alien object to visit our solar system is wrapped in strange organic coat

ANDREW GRIFFIN

‘It was the opposite of what I was expecting we might see’

The first ever interstellar visitor to our solar system is wrapped in a layer of organic insulation, scientists have said.

Oumuamua has enthralled astronomers and the public since it flew through the solar system in October.

As the first alien rock to travel here from another star, it was immediately recognised as highly unusual – but as scientists learn more about the object, they are discovering how strange it actually is.

Its strangeness has even led to suggestions it could be an alien artefact, rather than just an incredibly abnormal natural object.

Very little is known about what Oumuamua is, where it came from, and what it is made up of. Scientists had relatively little time to study the object as it passed through our solar system, and they are continuing to analyse the data that was obtained.

Before the rock arrived, scientists had expected that visitors of its kind would look like comets as they flew through the solar system. Such items would be made up of ice that would leave a visible stream behind them as they travelled past hot stars, they suggested.

But when Oumuamua flew past, no such activity was detected, despite flying close to the sun on its journey.

Now scientists taking part in different studies have released detailed findings on what the rock looks like and what it might be made of.

While it is probably an icy body as expected, it appears to be wrapped in an organic coat that shields the frozen water inside from being hit by the sun, according to the new research.

“In the end this was a nice result because we’ve expected all along that the majority of objects that would visit our solar system would be icy in nature,” said Alan Fitzsimmons from Queen’s University Belfast and the lead author of one of two major new studies into Oumuamua.

“It has been a puzzle that this thing looked like a big lump of rock.

“Our study says that this object could well be icy in nature but we didn’t detect that ice due to the fact it’s been baked by energetic radiation between the stars for hundreds of millions of years, or even billions of years.”

It is not certain that Oumuamua has any ice at all – the conclusion of Professor Fitzsimmons’ work is only that it can’t be ruled out. But that is because it is wrapped by its strange organic coat, and scientists can only see the very thinnest layer at the top of the object.

The coat was examined by using spectroscopy, which looks at the light being reflected from its surface and splits it down into its wavelengths. By looking at those measurements, scientists can work out what the object might be composed of.

“What we didn’t see is the signatures of the rocks you’d usually find on Earth, or you might find on the inner asteroid belt surrounding our sun,” Professor Fitzsimmons said.

It appeared red, but when looked at through infrared light it became more grey in colour. That was expected – it is what would normally come back from icy objects in our own solar system – but there did not actually appear to be any ice water coming off the surface.

Normally, ice is expected fall off such an object as it flies by the sun and the ice is warmed, forming a miniature comet.

“Looking at it we realised it had been predicted that icier objects exposed to interstellar space should naturally form a thick crust around themselves, said Professor Fitzsimmons.

“When we crunched the numbers we found that this crust should insulate the interior of the object so that if there were any ices inside it, it wouldn’t change the form.”

Scientists had long expected that we are sometimes visited by such rocks, thrown from elsewhere in the universe into our solar system.

We know that significant numbers of comets and asteroids were thrown out of our solar system when it was formed, and so can reasonably assume that the same thing happened in other planetary systems.

But they are difficult to spot since they are so dark, and none had actually been seen until now, marking an unprecedented breakthrough.

“In some ways we had expected these things for some time,” said Michele Bannister, also from Queen’s University Belfast and the author of another study of the strange rock.

“Our own solar system has ejected millions of very small rocky bodies,and so we should expect that others do the same.”

Both of the new studies attempted to understand how the rock looks and what exactly it might be made of. Professor Fitzsimmons used spectroscopy and thermal modelling to try to understand the rock’s composition, while Dr Bannister’s research observed the colour of Oumuamua and used that to try to discover how it looked.

Studying the rock also gives a unique opportunity to understand how other stars formed and how objects might cope with the harsh environment of space, by giving us a direct look at something that has endured it.

The work was destined to find something of interest either way, since the rock is such a strange visitor and is very old. “It’s travelled for millions or billions of years – it could be older than our solar system,” said Dr Bannister.

The work to find what colour it is, for instance, found that the rock appeared to be red. But the exact kind of red – which could indicate what it is made of – appears to vary, with some initial observations suggesting a dark colour while others showed it being more neutral.

Those neutral colours were largely in line with some of the objects we see in our own solar system.

“It’s come from a very long way away, but it looks very familiar,” said Dr Bannister. “It was the opposite of what I was expecting we might see.”

Dr Bannister has been working on a project called the Outer Solar System Origins Survey. That work uses telescopes to measure the colours of objects in the distant reaches of our solar system, and has developed techniques to help understand what those far away rocks might look like – difficult, when they are so dark and far away that little light comes back.

So when Oumuamua flew past, Dr Bannister and her colleagues looked to do the same thing for this rock, and “see if we can put this object in context with this really well-characterised set of objects”. They began observations soon after it was first detected.

That was doubly important because the trajectory that the rock was coming towards us from meant that we did not actually see it until it had gone past the Earth.

So there was a rapid effort to turn all the facilities that might help to look at it and learn as much as possible before it was too distant.

Scientists hope they can spot the next object quicker, after waiting 19 years for this one.

Oumuamua was first spotted on 19 October, by the Pan-STARRS project that uses a range of different technologies to observe the sky. Scientists realised very quickly that it was both an unprecedented visit from outside the solar system and that they would have very little time to get a look at it before it disappeared, meaning they rushed to learn as much about it as they could.

“It took a few days for everyone to be convinced that the orbit truly was from outside the solar system,” said Dr Bannister. “With the next one, hopefully that’ll happen more quickly.

“It’s been 19 years, and you do see comets that have interesting trajectories that then turn out to be from our solar system – from the Oort Cloud, 40,000-60,000 times as far from the sun as we are.

“Sometimes comets coming from that that can look like they’re coming from outside the solar system, so there was a certain degree of caution.”

“What we’re hoping for is not to do anything different,” said Professor Fitzsimmons. “Astronomers around the world threw everything at it.

“But what we’d really like is more warning. More time means more data, and more ability to figure out what we want to learn.”

Spotting another object from outside our solar system will be just as interesting as the first one: going from having seen one visitor to two means that we can start trying to understand how typical or strange Oumuamua is.

“What would be great would be to find another one of these objects where we can say, ‘yes, this object came from this particular star or particular region’,” said Professor Fitzsimmons. “At the moment the only limit we’ve got is an upper limit of about 10 billion years – because when our universe started, the materials weren’t around to form a solid body like this.”

“There’s definitely going to be a lot more work to be done,” says Dr Bannister. The rock is still being watched as it leaves the solar system, and in useful ways – by tracking its trajectory as it leaves, we can learn more about the path it might have come in on.

“It’s too far away now; it can just about be detected by the best telescopes we’ve got,” said Professor Fitzsimmons. “The important thing is for us to be ready for the next one.

“And it might take a few years for the next one to be detected, but the UK is already part of a project building the next-generation survey telescope down in Chile – when that gets finished we’re hoping for one a year.”

Until then, researchers will keep looking through the detailed and extensive data that has been generated about Oumuamua. We might not know everything until well into next year, when more data becomes available.

The object is very thin and very long – just what you’d design for long-distance space travel – and appears to be taking a strange trajectory. Those strange characteristics have led the Breakthrough Listen project, supported by Stephen Hawking, to point telescopes at Oumuamua and see if any radio transmissions can be heard.

There are enough surprises about the rock already without it being an alien object said Professor Fitzsimmons. And besides, strange though it is, Oumuamua does at least look like what you’d expect to have been created in the violent beginnings of a solar system like ours.

“If you’ve got a radio telescope why not do that?” he says when asked about the excitement around Oumuamua’s potential alien owners. “However, we expect these things to exist, because we expect such things to be flung out of all solar systems when they form planets.

“So we expect these things out there. And looking at this object, the first object that’s been detected, it has appearances of these natural objects that we’d expect from another star – this looks exactly what we’d expect.”

Comments

Space

NASA has banned fighting and littering on the moon

New details of the agreement signed by representatives of a number of countries on the development of the moon and the extraction of minerals within the framework of the Artemis program have appeared. Reported by the National Aeronautics and Space Administration (NASA).

So, astronauts involved in the mission are prohibited from littering and fighting on the territory of a natural satellite of the Earth.

So, we present to you the new rules for being on the Moon:

Everyone comes in peace;

Confidentiality is prohibited, all launched objects must be identified and registered;

All travel participants agree to help each other in case of emergencies;

All received data is transferred to the rest of the participants, and space systems must be universal;

Historic sites must be preserved and all rubbish must be disposed of;

Rovers and spacecraft should not interfere with other participants.

“”It is important not only to go to the moon with our astronauts, but also that we bring our values ​​with us,” said Mike Gold, acting head of NASA’s international and inter-agency relations.

According to him, violators of the above rules will be asked to “just leave” the territory of the moon.

The effect of these principles so far applies to eight signatory countries of the agreement: the USA, Australia, Canada, Italy, Japan, Luxembourg, the United Arab Emirates and the United Kingdom. Countries other than China can join if they wish.

 It should be noted that at the moment NASA is prohibited from signing any bilateral agreements with the PRC leadership.

The first NASA mission to the moon, known as “Artemis 1”, is scheduled for 2021 without astronauts, and “Artemis 2” will fly with a crew in 2023.

Continue Reading

Space

Methane snow found on the tops of Pluto’s equatorial mountains

Scientists believe that it arose as a result of the accumulation of large amounts of methane at an altitude of several kilometers above the surface of the planet.

In the images of the Cthulhu region – a dark region in the equatorial regions of Pluto – planetary scientists have found large reserves of methane snow that covers the peaks of local mountains and hills. It formed quite differently from how snow forms on Earth, astronomers write in the scientific journal Nature Communications.

“The white caps on the tops of Pluto’s mountains did not arise from the cooling of air currents that rise along the slopes into the upper atmosphere, as it happens on Earth, but from the accumulation of large amounts of methane at an altitude of several kilometers above Pluto’s surface. This gas condensed on the mountain tops, “the scientists write.

We owe almost everything we know about Pluto to the New Horizons interplanetary station. It was launched in January 2006, and in mid-July 2015 the station reached the Pluto system. New Horizons flew just 13 thousand km from the dwarf planet, taking many photographs of its surface. 

New Horizons data indicated an interesting feature of Pluto – in its depths, a giant subglacial ocean of liquid water can be hidden. It can be a kind of engine of those geological processes, traces of which can be seen on the surface of a dwarf planet. Because of this discovery of New Horizons, many discussions began among planetary scientists. Scientists are trying to understand how such a structure could have arisen, as well as to find out the appearance of Pluto in the distant past.

Members of the New Horizons science team and their colleagues from France, led by planetary scientist from NASA’s Ames Research Center (USA) Tanguy Bertrand, have discovered another unusual feature of Pluto. They studied the relief of one of the regions of the dwarf planet – the Cthulhu region. This is what astronomers call a large dark region at Pluto’s equator, which is whale-like in shape and is covered in many craters, mountains and hills.

Snow in Pluto’s mountains

By analyzing images of these structures taken by the LORRI camera installed on board New Horizons, astronomers have noticed many blank spots on the slopes of the highest mountain peaks. Having studied their composition, scientists have found that they consist mainly of methane.

Initially, planetary scientists assumed that these are deposits of methane ice. However, Bertrand and his colleagues found that the slopes and even the tops of Pluto’s equatorial mountains are actually covered not only with ice, but also with exotic methane snow that forms right on their surface.

Planetary scientists came to this conclusion by calculating how methane behaves in Pluto’s atmosphere. In doing so, they took into account how the molecules of its gases interact with the sun’s rays and other heat sources. It turned out that at the equator of Pluto, at an altitude of 2-3 km from its surface, due to the special nature of the movement of winds, unique conditions have formed, due to which snow is formed from methane vapor.

Unlike Earth, where such deposits are formed as a result of the rise of warm air into the upper atmosphere, on Pluto this process goes in the opposite direction – as a result of contact of the cold surface of the peaks and slopes of mountains with warm air masses from the relatively high layers of the dwarf planet’s atmosphere.

Previously, as noted by Bertrand and his colleagues, scientists did not suspect that this was possible. The fact is that they did not take into account that due to the deposition of even a small amount of methane snow and ice, the reflectivity of the peaks and slopes of mountains in the Cthulhu region increases. As a result, their surface temperature drops sharply, and snow forms even faster.

Scientists suggest that another mysterious feature of Pluto’s relief could have arisen in a similar way – the so-called Tartarus Ridges, located east of the Sputnik plain. A distinctive feature of this mountainous region is strange peaks that are shaped like skyscrapers or blades. Bertrand and his colleagues suggest that these peaks are also methane ice deposits that grow “from top to bottom.”

Continue Reading

Space

First exoplanet discovered in another galaxy

The Chandra X-ray Space Telescope has found the first potential exoplanet in another galaxy. The planet orbits in a binary star system in a galaxy 23 million light-years away and was discovered by the eclipse of its star, a compact, ultra-powerful X-ray source.

A new method for searching for exoplanets, which is also suitable for studying other galaxies, is to register a decrease in the brightness of powerful X-ray sources (degenerate stars), which is caused by the transit of the planet. Thus, it was possible to detect the object M51-ULS-1b in the spiral galaxy M51 (the “Whirlpool” galaxy in the constellation of the Dog Hounds), which may be a gas giant or a brown dwarf in the X-ray binary system. An article by astronomers at the Harvard-Smithsonian Center for Astrophysics about this possible discovery appeared in September 2020 and is still available as a preprint at arXiv.org; it will probably be published later in the Monthly Notices of the Royal Astronomical Society (MNRAS).

The Whirlpool Galaxy, or M51, is a spiral galaxy 23 million light years distant. It is distinguishable through binoculars (apparent stellar magnitude about + 8ᵐ), and it is easy to find it in the northern sky near the extreme star of the Big Dipper bucket, although formally the site belongs to the neighboring constellation of Hounds.

It is one of the first extragalactic objects to be photographed in the middle of the 19th century. The galaxy has a companion – the neighboring dwarf galaxy NGC 5195, which it gradually eats, so a pair of galaxies looks spectacular in the pictures. It is assumed that the painting by Van Gogh “Starry Night” depicts this very object, which was then well known for publishing astronomical sketches in magazines.

The Maelstrom nebula (possibly) in a painting by Van Gogh (1889).

Extragalactic planets are objects in star systems or lonely planets outside our Galaxy. Most of the about 6,000 exoplanets discovered today orbit around stars at distances of up to hundreds of light years, that is, they belong to the nearest galactic environs. 

More distant stars, even within the Galaxy, are beyond the scope of studying their planetary systems. Moreover, this applies to objects in other galaxies at distances of millions of light years (for example, the distance to the center of our Galaxy is 25 thousand light years, and the nearest giant galaxy Andromeda is located at a distance of 2.5 million light years). Nevertheless, several extragalactic candidate planets are known. 

They were all discovered by the method of gravitational microlensing (distortion of the trajectory of light rays from a distant light source in the gravitational field of a star and its planetary system). 

This is an indirect method, and at extragalactic distances there is practically no possibility to independently confirm the discovery of an exoplanet by other means. Object M51-ULS-1b became the first extragalactic planet, which was discovered by the method of transit, standard for the study of “near” exoplanets – observations of periodic “eclipses” by the planet of its star in the process of moving in orbit. 

The transit method is one of two popular methods for exploring nearby exoplanets, along with the radial velocity method. Currently, the TESS space telescope is in orbit, the main task of which is to monitor several thousand of the nearest stars in the entire celestial sphere and search for their planets in this way (for more details about this NASA project, there is a separate article on our website). 

A similar problem was previously solved by the Kepler space telescope, which has already completed its work. The main difference between the two projects is that TESS monitors almost the entire sky sector-by-sector, exploring stars at distances of up to 100-200 light years, while Kepler focused on a small area, but captured stars at distances of up to 3 thousand light years (there is also note on the site). 

But extragalactic distances are orders of magnitude greater, and precise observations of the brightness of ordinary stars even in neighboring galaxies are not yet possible. 

Therefore, only superbright objects are suitable for research in other galaxies (not necessarily stars that are bright in the optical range). So far, these are X-ray sources, which are most often binary systems, where a compact object (black hole or neutron star) actively absorbs the matter of the companion star.

X-ray image of the galaxy M51 by the Chandra telescope and the position of the X-ray source M 51-ULS at the edge of the young star cluster in a detailed Hubble image. Di Stefano et al. (2020).


There can be up to several hundred such objects in galaxies. In the above Chandra image of M51 (left), they appear as bright dots. If the system contains a large exoplanet, then it can cause a short-term full or partial drop in the brightness of the source in the X-ray range, similar to the optical transit that telescopes can track.

 The very first exoplanets discovered in the mid-1990s in our Galaxy were also found near such exotic objects. Subsequently, when the number of exoplanets began to be measured in thousands, interest for obvious reasons shifted to planets in star systems similar to the Sun (or even better – in their “zones of potential habitability” and preferably closer, for example, near Proxima Centauri).

A group at the Harvard-Smithsonian Center for Astrophysics searched for transit events among 2,624 archived light curves for more than two hundred X-ray sources in spiral galaxies M51 , M101, and  M104, according to the Chandra orbiting telescope . 

Two other objects here are also familiar to astrolamists – these are the photogenic galaxies “Pinwheel” in Ursa Major (M101) and “Sombrero” in Virgo (M104), well oriented for observations in relation to us. One of the cases found is in good agreement with the light curve in the single transit model. It belongs to the X-ray source designated M51-ULS-1 – a young massive binary system closer to the outskirts of the galaxy M51. 

The object that caused the source to completely darken for 20-30 minutes could theoretically belong to several classes, including rocky or gas planets, as well as stars – white dwarfs or M-class stars (ordinary stars are red dwarfs). 

The properties of the light curve, according to the authors, exclude the “stellar” nature of this object, which received the “exoplanetary” designation M51-ULS-1b… It is assumed that it is slightly smaller than Saturn and may be a hot gas giant or a substellar object – a brown dwarf. It moves in an orbit of a large radius (according to estimates – tens of astronomical units) and at one time survived a supernova explosion in this binary system, which led to the formation of a compact X-ray object. 

The authors of the work suggest that the method can be used to search for exoplanets both in other galaxies and in the Milky Way, and its accuracy will increase with the quality of data from orbiting telescopes.

Whirlpool Galaxy M51 and companion by Hubble
Galaxies M51 (“Whirlpool”) and NGC 5195 – image from the Hubble telescope . NASA / ESA / STScI .

Continue Reading
Advertisement

DO NOT MISS

Trending