Evan Gough, Author at Universe Today

April 8, 2016April 12, 2016 by Evan Gough

A Star With A Disk Of Water Ice? Meet HD 100546

Young stars have a disk of gas and dust around them called a protoplanetary disk. Credit: NASA/JPL-Caltech

It might seem incongruous to find water ice in the disk of gas and dust surrounding a star. Fire and ice just don’t mix. We would never find ice near our Sun.

But our Sun is old. About 5 billion years old, with about 5 billion more to go. Some younger stars, of a type called Herbig Ae/Be stars (after American astronomer George Herbig,) are so young that they are surrounded by a circumstellar disk of gas and dust which hasn’t been used up by the formation of planets yet. For these types of stars, the presence of water ice is not necessarily unexpected.

Water ice plays an important role in a young solar system. Astronomers think that water ice helps large, gaseous, planets to form. The presence of ice makes the outer section of a planetary disk more dense. This increased density allows the cores of gas planets to coalesce and form.

Young solar systems have what is called a snowline. It is the boundary between terrestrial and gaseous planets. Beyond this snowline, ice in the protoplanetary disk encourages gas planets to form. Inside this snowline, the lack of water ice contributes to the formation of terrestrial planets. You can see this in our own Solar System, where the snowline must have been between Mars and Jupiter.

A team of astronomers using the Gemini telescope observed the presence of water ice in the protoplanetary disk surrounding the star HD 100546, a Herbig Ae/Be star about 320 light years from us. At only 10 million years old, this star is rather young, and it is a well-studied star. The Hubble has found complex, spiral patterns in the disk, and so far these patterns are unexplained.

HD 100546 is also notable because in 2013, research showed the probable ongoing formation of a planet in its disk. This presented a rare opportunity to study the early stages of planet formation. Finding ice in the disk, and discovering how deep it exists in the disk, is a key piece of information in understanding planet formation in young solar systems.

Finding this ice took some clever astro-sleuthing. The Gemini telescope was used, with its Near-Infrared Coronagraphic Imager (NICI), a tool used to study gas giants. The team installed H2O ice filters to help zero in on the presence of water ice. The protoplanetary disk around young stars, as in the case of HD 100546, is a mixed up combination of dusts and gases, and isolating types of materials in the disk is not easy.

Water ice has been found in disks around other Herbig Ae/Be stars, but the depth of distribution of that ice has not been easy to understand. This paper shows that the ice is present in the disk, but only shallowly, with UV photo desorption processes responsible for destroying water ice grains closer to the star.

It may seem trite so say that more study is needed, as the authors of the study say. But really, in science, isn’t more study always needed? Will we ever reach the end of understanding? Certainly not. And certainly not when it comes to the formation of planets, which is a pretty important thing to understand.

April 7, 2016April 15, 2016 by Evan Gough

Supermassive Black Hole Found In The Cosmic Boonies

A supermassive black hole has been found in an unusual spot: an isolated region of space where only small, dim galaxies reside. Image credit: NASA/JPL-Caltech — A team of astronomers from South Africa have noticed a series of supermassive black holes in distant galaxies that are all spinning in the same direction. Credit: NASA/JPL-Caltech

Astronomers have found a massive black hole in a place they never expected to find one. The hole comes in at 17 billion solar masses, which makes it the second largest ever found. (The largest is 21 billion solar masses.) And though its enormous mass is noteworthy, its location is even more intriguing.

Supermassive black holes are typically found at the centers of huge galaxies. Most galaxies have them, including our own Milky Way galaxy, where a comparatively puny 4 million solar mass black hole is located. Not only that, these gargantuan holes tend to be located in galaxies that are part of a large cluster of galaxies. Being surrounded by all that mass is a prerequisite for the formation of supermassive black holes. The largest one known, at 21 billion solar masses, is located in a very dense region of space called the Coma Cluster, where over 1,000 galaxies have been identified.

The largest supermassive holes also tend to be surrounded by bright companions, who have also grown large from the plentiful mass in their surroundings. (Of course, its not the black holes that are bright, but the quasars that surround them.) The long and the short of it is that supermassive black holes are usually found in galaxy clusters, and usually have other supermassive companions in the same region of space. They’re not found in isolation.

But this newly found black hole is in a rather sparse region of space. It’s in NGC 1600, an elliptical galaxy in the constellation Eridanus, 200 million light years from Earth. NGC 1600 is not a particularly large galaxy, and though it has been considered part of a larger group of galaxies, all its companions are much dimmer in comparison. So NGC 1600 is a rather small, isolated galaxy, with only a few dim companions.

A supermassive black hole of 17 billion solar masses has been found in the elliptical galaxy NGC 1600, a rather isolated galaxy with only dim companions. To date, supermassive black holes have only been found in huge galaxies at the centre of large clusters of galaxies. This image is a composite image from the Hubble and from ground observatories. Image Credit: NASA/ESA/Digital Sky Survey 2.

There’s another way that supermassive holes can form. Instead of growing large over time, by feeding on the mass of their home galaxies and galaxy clusters, they can form when two galaxies merge, and two smaller holes become one. But even this requires that they be in a region where galaxies are plentiful, allowing for more collisions and mergers.

It may be possible that NGC is the result of a merger of two galaxies, or that it is two black holes that are currently merging. Or it could be that NGC 1600’s region of space was once extremely rich in gas, in the early days of the Universe, and that’s what gave rise to this ‘out of place’ supermassive black hole.

There is much to be learned about the conditions that give rise to these behemoth black holes. The MASSIVE study will combine several telescopes to survey and catalogue the largest galaxies and black holes. This should tell astronomers a lot about their distribution, and about the circumstances that allow them to exist. We might find even larger ones.

April 6, 2016April 15, 2016 by Evan Gough

New Horizons Did Amazing Work Before Even Arriving At Pluto

The solar wind data collected by New Horizons will help create more accurate models of the space environment in our Solar System. Image: NASA's Goddard Space Flight Center Scientific Visualization Studio, the Space Weather Research Center (SWRC) and the Community-Coordinated Modeling Center (CCMC), Enlil and Dusan Odstrcil (GMU)

Anybody with an ounce of intellectual curiosity (and an internet connection) has seen the images of Pluto and its system taken by the New Horizons probe. The images and data from New Horizons have opened the door to Pluto’s atmosphere, geology, and composition. But New Horizons wasn’t entirely dormant during its 9 year, billion-plus mile journey to Pluto.

New Horizons returned 3 years worth of data on the solar wind that sweeps through the near-emptiness of space. The solar wind is the stream of particles that is released from the upper atmosphere of the Sun, called the corona. The Sun’s solar wind is what creates space weather in our solar system, and the wind itself varies in temperature, speed, and density.

The solar wind data from New Horizons, which NASA calls an “unprecedented set of observations,” is filling in a gap in our knowledge. Observatories like the Solar Dynamics Observatory (SDO) and the Solar and Heliospheric Observatory (SOHO) are studying the Sun up close, and the Voyager probes have sampled the solar wind near the edge of the heliosphere, where the solar wind meets interstellar space, but New Horizons is giving us our first look at the solar wind in Pluto’s region of space.

This solar wind data should shed some light on a number of things, including the dangerous radiation astronauts face when in space. There is a type of particle with extreme energy levels called anomalous cosmic rays. When travelling close to Earth, these high-velocity rays can be a serious radiation hazard to astronauts.

The data from New Horizons reveals particles that pick up an acceleration boost, which makes them exceed their initial speed. It’s thought that these particles could be the precursors to anomalous cosmic rays. A better understanding of this might lead to a better way to protect astronauts.

These same rays have other effects further out in space. It looks like they are partly responsible for shaping the edge of the heliosphere; the region in space where the solar wind meets the interstellar medium.

New Horizons has also told us something about the structure of the solar wind the further it travels from the Sun. Close to the Sun, phenomena like coronal mass ejections (CMEs) have a clearly discernible structure. And the differences in the solar wind, in terms of velocity, density, and temperature, are also discernible. They’re determined by the region of the Sun they came from. New Horizons found that far out in the solar system, these structures have changed.

“At this distance, the scale size of discernible structures increases, since smaller structures are worn down or merge together,” said Heather Elliott, a space scientist at the Southwest Research Institute in San Antonio, Texas, and the lead author of a paper to be published in the Astrophysical Journal. “It’s hard to predict if the interaction between smaller structures will create a bigger structure, or if they will flatten out completely.”

The Voyager probes measured the solar wind as they travelled through our Solar System into the interstellar medium. They’ve told us a lot about the solar wind in the more distant parts of our system, but their instruments aren’t as sensitive and advanced as New Horizons’. This second data set from New Horizons is helping to fill in the blanks in our knowledge.

April 6, 2016April 15, 2016 by Evan Gough

Mysterious Pull On Cassini Probe May Help Find Planet Nine

Artist's impression of Planet Nine, blocking out the Milky Way. The Sun is in the distance, with the orbit of Neptune shown as a ring. Credit: ESO/Tomruen/nagualdesign

Finding a ninth planet in our Solar System this late in the game would be fascinating. It would also be somewhat of a surprise, considering our observational capabilities. But new evidence, in the form of small perturbations in the orbit of the Cassini probe, points to the existence of an as-yet undetected planet in our solar system.

Back in January, Konstantin Batygin and Mike Brown, two planetary scientists from the California Institute of Technology, presented evidence supporting the existence of a ninth planet. Their paper showed that some Kuiper Belt Objects (KBOs) display unexpected behaviour. It appears that 6 KBOs are affected by their relationship to a large object, but the KBOs in question are too distant from the known gas giants for them to be responsible. They think that a large, distant planet, in the distant reaches of our Solar System, could be responsible for the unexpected orbital clustering of these KBOs.

The calculated orbit of Planet Nine. Credit: Nature/K. Batygin and M. E. Brown Astronom. J. 151, 22 (2016)

Now, the Ninth Planet idea is gaining steam, and another team of researchers have presented evidence that small perturbations in the orbit of the Cassini spacecraft are caused by the new planet. Agnès Fienga at the Côte d’Azur Observatory in France, and her colleagues, have been working on a detailed model of the Solar System for over a decade. They plugged the hypothetical orbit and size of Planet Nine into their model, to see if it fit.

Planet Nine is calculated to be about 4 times as large as Earth, and 10 times as massive. It’s orbit takes between 10,000 and 20,000 years. A planet that large can only be hiding in so many places, and those places are a long way from Earth. Fienga found a potential home for Planet Nine, some 600 astronomical units (AU) from here. That much mass at that location could account for the perturbations in Cassini’s orbit.

There’s more good news when it comes to Planet Nine. By happy accident, it’s predicted location in the sky is towards the constellation Cetus, in the southern hemisphere. This means that it is in the view of the Dark Energy Survey, a southern hemisphere project that is studying the acceleration of the universe. The Dark Energy Survey is not designed to search for planetary objects, but it has successfully found at least one icy object.

There are other ways that the existence of Planet Nine could be confirmed. If it’s as large as thought, then it will radiate enough internal heat to be detected by instruments designed to study the Cosmic Microwave Background (CMB). There is also an enormous amount of data from multiple experiments and observations done over the years that might contain an inadvertent clue. But looking through it is an enormous task.

As for Brown and Batygin, who initially proposed the existence of Planet Nine based on the behaviour of KBOs, they are already proposing a more specific hunt for the elusive planet. They have asked for a substantial amount of observing time at the Subaru Telescope on Mauna Kea in Hawaii, in order to examine closely the location that Fienga’s solar system model predicts Planet Nine to be at.

For a more detailed look at Batygin’s and Brown’s work analyzing KBOs, read Matt Williams’ article here.

April 4, 2016April 15, 2016 by Evan Gough

Gender Generates Biological Challenges For Long Duration Spaceflight

Astronaut Bruce McCandless untethered above the Earth on Feb. 12, 1984. (NASA)

Men and women look exactly the same when ensconced in a space suit. But female physiology is different from male physiology in significant ways. And those differences create challenges when those bodies have to endure long duration spaceflight, such as during proposed missions to Mars.

Some of the effects of spending a long time in space are well-known, and affect both genders. Exposure to microgravity creates most of these effects. With less gravity acting on the body, the spine lengthens, causing aches and pains. Lowered gravity also causes bone loss, as the skeletal system loses important minerals like nitrogen, calcium, and phosphorous. And the muscles atrophy, since they aren’t used as much.

Microgravity makes the body sense that it is carrying too much fluid in the chest and head, and the body tries to eliminate it. Astronauts feel less thirst, and over time the body’s fluid level decreases. With less fluid, the heart doesn’t have to work as hard. The heart’s a muscle, so it atrophies much like other muscles. The fluid level causes other changes too. Fluid accumulates in the face, causing “Puffy Face Syndrome.”

But some problems are specific to gender, and Gregor Reid, PhD, and Camilla Urbaniak, PhD Candidate at the Shulich School of Medicine and Dentistry are focusing on one fascinating and important area: the human microbiome. Female and male microbiomes are different, and they are affected by microgravity, and other aspects of space travel, in different ways.

The human microbiome is the trillions of microorganisms living on the human body and in the gut. They are important for digestion and nutrition, and also for the immune system. A healthy human being requires a healthy microbiome. If you’ve ever travelled to another part of the world, and had stomach problems from the food there, those can be caused by changes in your microbiome.

Research on astronauts shows that spending time in space changes different aspects of the microbe population in a human being. Some of these changes cause health complications when the microbes responsible for digestion and immunity are affected. Reid says that the microbe has to be understood as its own organ, and we need a better understanding of how to keep that organ healthy. Keeping the microbiome healthy will keep the astronaut healthy, and reduce the risk of disease.

After conducting a literature review, the two researchers suggested that astronauts should incorporate probiotics and fermented foods into their diet to boost the health of their microbiome. They think that astronauts should have access to probiotic bacteria that they can prepare food with. Urbaniak acknowledges that female astronauts don’t want to be limited to shorter duration space flights, and using probiotics to manipulate the microbiome of female astronauts will allow them to withstand longer voyages.

Reid and Urbaniak also highlight some other problems facing women in long distance space voyages. If a female astronaut is diagnosed with breast cancer, ovarian cancer, or a urinary tract infection during an extended journey in space, any treatment involving antibiotics would be problematic. The antibiotics themselves may work less effectively due to changes in the microbiome.

Research on male astronauts has already shown a decrease in beneficial microorganism in the gut, and in the nasal and oral pathways. Those decreases were noted in both long and short duration stays in space. The research also shows an increase in harmful microorganisms such as E. coli. and staphylococcus. But so far, the same research hasn’t been done on female astronauts.

It’s well understood that women and men have different microbial profiles, and that their microbiomes are different. But there’s a lot we still don’t know about the specifics. This is an important area of research for NASA. According to Urbaniak, though, previous studies of the human microbiome and its response to space travel have focused on male astronauts, not female astronauts. Reid and Urbaniak are hopeful that their work will start a conversation that results in a greater understanding of the effects of space travel on women.

April 1, 2016 by Evan Gough

Don’t Want Aliens Dropping By? Engage Laser Cloaking Device

Lasers like this one, at the VLT in Paranal, help counteract the blurring effect of the atmosphere. Powerful arrays of much larger lasers could hide our presence from aliens. (ESO/Y. Beletsky)

Of course we all know that aliens want to take over Earth. It’s in all the movies. And after they take over, they could do whatever they want to us puny, weak Earthlings. Enslavement? Yup. Forced breeding programs? Sure. Lay eggs in our bellies and consume our guts for their first meal? Why not.

But here at Universe Today, we’re science-minded types. We love the science fiction, but don’t take it too seriously. But someone we do take seriously when he has something to tell us is Stephen Hawking. And when he warned us that aliens might want to conquer and colonize us, it lent gravity to the whole discussion around contact with aliens. Should we reach out to alien civilizations? Will we be safe if they find us? Or should we try to conceal our presence?

If we choose concealment, then a new paper from two astronomers at New York’s Columbia University have good news for humanity. The authors of the paper, Professor David Kipping and graduate student Alex Teachey, say that lasers could be used to hide Earth from alien prying eyes.

At the heart of this whole idea are transits. When a planet passes in between its star and a distant observer, the star’s light is dimmed, and that’s called a transit. This is how the Kepler spacecraft detects exo-planets, and it’s been remarkably successful. If alien species are using the same method, which makes sense, then Earth would be easily detectable in the Sun’s habitable zone.

According to Kipping and Teachey, lasers could be used to mask this effect. A 30 MW laser would be enough to counter the dimming effect of Earth’s transit in front of the Sun. And it would only need to be turned on for 10 hours, once every year, since that’s how long Earth’s transit takes.

But that would only take care of the dimming effect in visible light. To counter-act the transit dimming across the whole electromagnetic spectrum would require much more energy: a 250 MW cloak of lasers tuned all across the spectrum. But there might be a middle way.

According to an interview with the paper’s authors in Science Daily, it might take only 160 MW of lasers to mask biological signatures in the atmosphere. Any prying alien eyes would not notice that life had ever come into being on Earth.

Should we decide that we do indeed want to be colonized, or forced to take part in breeding programs, or be enslaved, then the same system of lasers could be used to amplify the transit effect. This would make it easier, rather than harder, for aliens to detect us. In fact, according to the authors, these lasers could even be used to communicate with aliens, by transmitting information.

Of course, there’s one other element to all this. For this to work, we have to know where to aim the lasers, which means we have to know where the alien civilization is. And if we’re worried about them coming to get us, they will have more advanced technology than us. And if they have more advanced technology than us, they will for sure already have laser cloaking like the type talked about here.

So who’ll be the first to blink, and turn off their laser cloaking and allow detection?

You first, aliens.

April 1, 2016April 15, 2016 by Evan Gough

Andromeda’s First Spinning Neutron Star Found

Andromeda's spinning neutron star. Though astronomers think there are over 100 million of these objects in the Milky Way, this is the first one found in Andromeda. Image: ESA/XMM Newton.

On a clear night, away from the bright lights of a city, you can see the smudge of the Andromeda galaxy with the naked eye. With a backyard telescope, you can take a good look at the Milky Way’s sister galaxy. With powerful observatories, it’s possible to see deep inside Andromeda, which is what astronomers have been doing for decades.

Now, astronomers combing through data from the ESA’s XMM Newton space telescope have found something rare, at least for Andromeda; a spinning neutron star. Though these objects are common in the Milky Way, (astronomers think there are over 100 million of them) this is the first one discovered in Andromeda.

A neutron star is the remnant of a massive star that went supernova. They are the smallest and most dense stellar objects known. Neutron stars are made entirely of neutrons, and have no electrical charge. They spin rapidly, and can emit electromagnetic energy.

If the neutron star is oriented toward Earth in just the right way, we can detect their emitted energy as pulses. Think of them as lighthouses, with their beam sweeping across Earth. The pulses of energy were first detected in 1967, and given the name pulsar.” We actually discovered pulsars before we knew that neutron stars existed.

Many neutron stars, including this one, exist in binary systems, which makes them easier to detect. They cannibalize their companion star, drawing gas from the companion into their magnetic fields. As they do so, they emit high energy pulses of X-ray energy.

The star in question, which astronomers, with their characteristic flair for language, have named 3XMM J004301.4+413017, spins rapidly: once every 1.2 seconds. It’s neighbouring star orbits it once every 1.3 days. While these facts are known, a more detailed understanding of the star will have to wait for more analysis. But 3XMM J004301.4+413017 does appear to be an exotic object.

“It could be what we call a ‘peculiar low-mass X-ray binary pulsar’ – in which the companion star is less massive than our Sun – or alternatively an intermediate-mass binary system, with a companion of about two solar masses,” says Paolo Esposito of INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan, Italy. “We need to acquire more observations of the pulsar and its companion to help determine which scenario is more likely.”

“We’re in a better position now to uncover more objects like this in Andromeda, both with XMM-Newton and with future missions such as ESA’s next-generation high-energy observatory, Athena,” added Norbert Schartel, ESA’s XMM-Newton project scientist.

This discovery is a result of EXTraS, a European Project that combs through XMM Newton data. “EXTraS discovery of an 1.2-s X-ray pulsar in M31” by P. Esposito et al, is published in the Monthly Notices of the Royal Astronomical Society, Volume 457, pp L5-L9, Issue 1 March 21, 2016.

March 30, 2016 by Evan Gough

Inflatable Space Habitat To Be Tested On The ISS

The Bigelow Expandable Activity Module (BEAM) will be launched onboard a SpaceX Dragon on Friday April 8th for a 2-year mission. Astronauts will test the module during that time. Image Bigelow Aerospace.

Space habitats have long been an object of fascination for thinkers, dreamers, and engineers. Science fiction is littered with space habitats, whether in books or movies. And their designs have ranged from titanic, uber-engineered types to fanciful, organic types.

Bigelow Aerospace is one company that is focused on creating affordable, practical space habitats. Inflatability is the name of the game for Bigelow, and now, one of their habitat modules is going to be tested on the ISS for a 2-year period. The BEAM, or Bigelow Expandable Activity Module, will be launched aboard a SpaceX Dragon on Friday April 8th, for a 2-day journey to the ISS.

The BEAM travels as an 8 foot bundle, but once it’s attached to the ISS, and inflated by astronauts, it will be large enough to hold a car. However, astronauts won’t be living inside it; rather, the BEAM will be tested for 2 years to see how it holds up. The objectives for this 2 year mission include:

Demonstrating launch and deployment, as well as folding and packing techniques.
Determining radiation protection capability.
Demonstrating design performance such as thermal, structural, mechanical durability, long-term leak performance, etc.
Increasing Technology Readiness Level (TRL) of expandable habitat technology

The BEAM with human figure for scale. Image: Bigelow Aerospace.

“The International Space Station is a uniquely suited test bed to demonstrate innovative exploration technologies like the BEAM,” said William Gerstenmaier, associate administrator for human exploration and operations at NASA Headquarters in Washington. “As we venture deeper into space on the path to Mars, habitats that allow for long-duration stays in space will be a critical capability. Using the station’s resources, we’ll learn how humans can work effectively with this technology in space, as we continue to advance our understanding in all aspects for long-duration spaceflight aboard the orbiting laboratory.”

The obvious risk to an inflatable space habitat is puncturing; not only from meteoroids, but from the growing population of space junk that inhabits Earth’s orbit. But BEAM is designed with this hazard in mind. It’s a thick-walled design, made from multiple layers of fabric similar to Kevlar. As far as space junk goes, BEAM should be impenetrable.

The BEAM is just a test module. It will hold only monitoring equipment, and will be entered by astronauts retrieving data and performing inspections. Bigelow Aerospace’s design for a usable habitat is the B330, a module large enough for 6 occupants, with a projected lifespan of 20 years. Test results from BEAM’s 2 years in space will help refine the design of the B330.

After its 2 years are up, BEAM will be released from the ISS and will be destroyed when it enters Earth’s atmosphere.

March 29, 2016 by Evan Gough

Japan’s Black Hole Telescope Is In Trouble

An artist's drawing of Japan's Hitomi observatory. Image Credit: JAXA/Akihiro Ikeshita

The Japanese Aerospace Exploration Agency (JAXA) has lost contact with its X-ray Astronomy Satellite Hitomi (ASTRO-H.) Hitomi was launched on February 17th, for a 3-year mission to study black holes. But now that mission appears to be in jeopardy.

Hitomi is a collaboration between JAXA and NASA. Its mission was to investigate how galaxy clusters were formed and influenced by dark matter and dark energy, and to understand how super-massive black holes form and evolve at the center of galaxies. Hitomi was also to “unearth the physical laws governing extreme conditions in neutron stars and black holes,” according to JAXA.

Japan has managed two very short communications with Hitomi, but they were very brief, and JAXA has not been able to determine the nature of the problem. Now, JSpOC, the US Joint Space Operations Center, say they have detected debris in the vicinity of Hitomi, and in a press release this morning (March 29th), JAXA says “it is estimated that Hitomi separated to five pieces at about 10:42 a.m.”

Hitomi was going to be an important contribution to the fleet of space telescopes used by astrophysicists and cosmologists. It has a cutting edge instrument called the X-ray micro-calorimeter, which would have observed X-rays from space with the greatest sensitivity of any instrument so far. If all that is lost, it will be quite a blow.

There’s no definitive word yet on what exactly has happened to Hitomi. Japan is using ground stations in different parts of the world to try to communicate with their observatory. It’s important to note that there is no agreement that the craft has broken apart. The press releases are translations from Japanese to English, so the exact meaning of “separated to five pieces” is unclear.

It’s possible that there was a small explosion of some sort, and that some debris from that explosion is in the vicinity of Hitomi. It’s also possible that JAXA will re-establish communications with the craft as time goes on.

Other observatories have suffered serious problems, and have eventually been brought back under control and completed their missions. The ESA/NASA Solar and Heliospheric Observatory (SOHO) suffered serious problems at the beginning of its mission in 1995, entering emergency mode 3 times before all contact was lost. Eventually, SOHO was brought under control, and what was supposed to be a 2-year mission has lasted 20.

Universe Today will be following this story to see if Hitomi can be made operational. For readers wanting to know more about Hitomi’s mission, read JAXA’s excellent Hitomi press kit.

March 24, 2016April 12, 2016 by Evan Gough

The Moon’s Other Axis

A six degree True Polar Wander occurred on the Moon due to ancient volcanic activity. Image: University of Arizona/James Tuttle Keane

It’s tempting to think that the Moon never changes. You can spend your whole life looking at it, and see no evidence of change whatsoever. In fact, the ancients thought the whole Universe was unchanging.

You may have heard of a man named Aristotle. He thought the Universe was eternal and unchanging. Obviously, with our knowledge of the Big Bang, stellar evolution, and planetary formation, we know better. Still, the placid and unchanging face of the Moon can tempt us into thinking astronomers are making up all this evolving universe stuff.

But now, according to a new paper in Nature, the Moon’s axis of rotation is different now than it was billions of years ago. Not only that, but volcanoes may been responsible for it. Volcanoes! On our placid little Moon.

The clue to this lunar True Polar Wander (TPW) is in the water ice locked in the shadows of craters on the Moon. When hydrogen was discovered on the surface of the Moon in the 1990s by the Lunar Prospector probe, scientists suspected that they would eventually find water ice. Subsequent missions proved the presence of water ice, especially in craters near the polar regions. But the distribution of that water-ice wasn’t uniform.

You would expect to see ice uniformly distributed in the shadows of craters in the polar regions, but that’s not what scientists have found. Instead, some craters had no evidence of ice at all, which led the team behind this paper to conclude that these ice-free craters must have been exposed to the Sun at some point. What else would explain it?

The way that the ice in these craters is distributed forms two trails that lead away from each pole. They’re mirror images of each other, but they don’t conform with the Moon’s current axis of rotation, which is what led the team to conclude that the Moon underwent a 6 degree TPW billions of years ago.

The paper also highlights the age of the water on the Moon. Since the TPW, and the melting of some of the ice as a result of it, occurred some billions of years ago, then the water ice that is still frozen in the shadows of some of the Moon’s craters must be ancient. According to the paper, its existence records the “early delivery of water to the inner Solar System.” Hopefully, a future mission will return a sample of this ancient water for detailed study.

But even more interesting than the age of the ice in the craters and the TPW, to me anyways, is what is purported to have caused it. The team behind the paper reports that volcanic activity on the Moon in the Procellarum region, which was most active in the early history of the Moon, moved a substantial amount of material and “altered the density structure of the Moon.” This alteration would have changed the moments of inertia on the Moon, resulting in a TPW.

It’s strange to think of the Moon with volcanic activity viewable from Earth. I wonder what effect visible lunar volcanoes would have had on thinkers like Aristotle, if lunar volcanic activity had occurred during recorded history, rather than ending one billion years ago or so.

We know that events like eclipses and comets caused great confusion and sometimes upheaval in ancient civilizations. Would lunar volcanoes have had the same effect?