Universe Today

October 26, 2016October 26, 2016 by Matt Williams

Evidence Continues To Mount For Ninth Planet

Artist's concept of the hypothetical "Planet Nine." Could it have moons? Credit: NASA/JPL-Caltech/Robert Hurt

Ever since its existence was first proposed, the evidence for Planet 9 continues to mount. But of course, said evidence has been entirely indirect, consisting mostly of studies that show how the orbits of Trans-Neptunian Objects (TNOs) are consistent with a large object crossing their path. However, evidence is also emerging that comes from the center of the Solar System itself.

This latest line of evidence comes from Caltech, where researchers Elizabeth Bailey, Konstantin Batygin, and Michael E. Brown (the latter of whom were the ones who first proposed Planet 9’s existence) have published a new study linking solar obliquity to the existence of Planet 9. Essentially, they claim that the axial tilt of the Sun (6°) could be due to the gravitational influence a large planet with an extreme orbit.

To recap, the issue of Planet was first raised in 2014 by astronomers Scott Sheppard and Chadwick Trujillo. Noting the similarities in the orbits of distant Trans-Neptunian Objects (TNOs), they postulated that a massive object was likely influencing them. This was followed in 2016 by Konstantin Batygin and Michael E. Brown of Caltech suggesting that an undiscovered planet was the culprit.

*The orbits of several KBOs provide indications about the possible existence of Planet 9. Credit: Caltech/R. Hurt (IPAC)*

Calling this body Planet 9, they speculated that it had a mass 10 times greater than that of Earth, and took 20,000 years to complete a single orbit of our Sun. They also speculated that its orbit was tilted relative to the other planets of our Solar System, and extremely eccentric. And little by little, examinations of other Solar bodies have shown that Planet 9 is likely out there.

For the sake of their study – “Solar Obliquity Induced by Planet Nine“, which was recently published in the Astrophysical Journal – the research team (led by Bailey) looked to the obliquity of the Sun. As they state in their paper, the six-degree axial tilt of the Sun can only be explained in one of two ways – either as a result of an asymmetry that was present during the formation of Solar System, or because of an external source of gravity.

To test this hypothesis, Bailey, Batygin and Brown used an analytic model to test how interactions between Planet 9 and the rest of the Solar System would effect their orbits over the course of the last 4.5 billion years. As Elizabeth Bailey, a graduate student at Caltech’s Division of Geological and Planetary Sciences and the lead author on the paper, told Universe Today via email:

“We simulated the solar system’s motion. Planet 9 forces the solar system to slowly wobble. If Planet 9 is out there, we are in the process of wobbling right now, as we speak! But it happens very slowly, a few degrees tilt per billion years. Meanwhile the sun is not wobbling much, so it looks like the sun is tilted. A range of Planet 9 parameters cause exactly the configuration of the sun that we see today.

*Animated diagram showing the spacing of the Solar Systems planet’s, the unusually closely spaced orbits of six of the most distant KBOs, and the possible “Planet 9”. Credit: Caltech/nagualdesign*

In the end, they concluded that the Sun’s obliquity could only be explained by the influence of giant planet with an extreme orbit, one that is consistent with the characteristics attributed to Planet 9. In other words, the existence of Planet 9 offers an explanation for the Sun’s peculiar behavior, something which has remained a mystery until now.

“Planet Nine was first hypothesized because the orbits of objects in the outer reaches of the solar system are confined in physical space,” said Bailey. “Those orbits would be all over the place unless something is currently stopping them. The only explanation so far is Planet Nine. For over 150 years, people have wondered why the sun is tilted. Personally I’d say that Planet 9 offers the first satisfying explanation. If it exists, it tilted the sun.”

In addition, the subject of Planet 9 was also raised at the joint 48th meeting of the American Astronomical Society’s Division for Planetary Sciences and 11th European Planetary Science Congress, which took place from Oct 16th to 21st in Pasadena, California. During the course of the meeting, researchers from Arizona University shared the results of their own study, which was published back in August.

The Arizona research team was led by Renu Malhotra, a Regents’ Professor of Planetary Sciences in the University of Arizona’s Lunar and Planetary Lab. For the sake of their study, titled “Corralling a Distant Planet with Extreme Resonant Kuiper Belt Objects“, they examined the orbital patterns of four extreme Kuiper Belt Objects (KBOs), which have the longest orbital periods of any known objects.

Artist's impression of the the possible Planet 9 at the edge of the Solar System. Credit: Robin Dienel/Carnegie Science — *Artist’s impression of the the possible Planet 9 at the edge of the Solar System. Credit: Robin Dienel/Carnegie Science*

According to their calculations, the presence of a massive planet – one that would complete an orbit around the Sun every 17,117 years, and at an average distance (semimajor axis) of 665 AU – would explain the orbital pattern of these four objects. These results were consistent with the estimates concerning the orbital period of Planet 9, its orbital path, and it mass.

“We analyzed the data of these most distant Kuiper Belt objects,” Malhotra said, “and noticed something peculiar, suggesting they were in some kind of resonances with an unseen planet… Our paper provides more specific estimates for the mass and orbit that this planet would have, and, more importantly, constraints on its current position within its orbit.”

Looks like Planet 9’s days of hiding in the outer Solar System may be numbered!

Further Reading: arXiv, Caltech, Europlanet

October 25, 2016October 25, 2016 by Nancy Atkinson

New ‘Selfie’ MicroSatellite Captures Images of Chinese Space Station

Banxing-2 snaps Tiangong-2 and Shenzhou-11 using a fisheye camera. (Credit: Chinese Academy of Sciences.

Here’s a great new view of China’s Tiangong II space station, taken by a new ‘selfie’ satellite. The Banxing-2 satellite is about the size of a desktop printer and was released from the station on Sunday. It has been nicknamed the “Selfie Stick” by Chinese officials and is taking pictures of the station and the docked Shenzhou XI spacecraft. The Chinese astronauts who boarded the station last week aren’t just joining the selfie craze; the 25 megapixel camera with wide-angle and infrared imagers has a specific job.

“The companion satellite monitors the conditions of Tiangong II and Shenzhou XI all the time, which is helpful in detecting failures,” said Chen Hongyu, chief engineer of the satellite program and a researcher with the Chinese Academy of Sciences’ Micro-satellite Innovation Institute.

The Banxing-2 microsatellite. Credit: China Daily.

The microsatellite as three solar panels, so can generate enough power to adjust its orbit to shoot pictures of the lab and spacecraft. Its predecessor, Banxing-1, accomplished the same mission for Shenzhou VII in 2008. The Chinese Academy of Sciences says the new model is smaller and has a higher capacity.

Now well into their 30-day mission, astronauts Jing Haipeng and Chen Dong boarded China’s second version of its “Heavenly Palace” last week. They launched Monday, October 17 from the Jiuquan Satellite Launch Center in the Gobi Desert on a Long March 2F rocket and Shenzhou-11 completed a fully automated approach and docking to Tiangong-2 on Tuesday.

During their mission, the two crew members will perform experiments from 14 different areas including biology, space life science and technological demonstrations. They have set up plant cultivation and growing experiments and have six silkworms on board for a student-based study to see how silkworms produce silk in microgravity. The crew is also doing medical testing on themselves using Tiangong II’s on board ultrasound equipment to scan their cardiovascular and pulmonary systems. They’ll also be checking for bone and muscle degradation and track any changes to their eyesight. NASA and ESA has discovered that the majority of astronauts doing long-duration space flights on the International Space Station have suffered various kinds of vision problems while in space, or upon their return.

This 30-day medium duration mission is China’s longest space mission to date, and the main task of the Tiangong crew is to help prepare for longer future missions on a larger, modular space station that, according to reports, China hopes to launch by 2018.

Further reading: Chinese Academy of Sciences, Spaceflight 101.

October 25, 2016October 27, 2016 by Susie Murph

Carnival of Space #480

Carnival of Space. Image by Jason Major.

Welcome, come in to the 480th Carnival of Space! The Carnival is a community of space science and astronomy writers and bloggers, who submit their best work each week for your benefit. I’m Susie Murph, part of the team at Universe Today and CosmoQuest. So now, on to this week’s stories!
Continue reading “Carnival of Space #480”

October 25, 2016 by Mark Mortimer

Book Review: A History of the Solar System

The value of a good analyst is priceless. They can synthesize data from disparate sources and weave a reasonable story to bring sense out of historical events and to provide guidance to planning for the future. Adding a sense of scale to space analysis so as to make things relevant to people living on the Earth today adds even more to their value. This is what Claudio Vita-Finzi provides in his book “A History of the Solar System.” It’s a collection of analyses of our grand backyard from a variety of perspectives and it offers great value to the reader.

We know so much about our solar system. And at the same time we realize that we know so little. That’s the main story of this book. It notes the common lore: there are planets, asteroids, comets and dust. That’s today. Long, long ago, a great expanse of dust got localised and made the Milky Way, so at least is postulated in the book. The future should see our Sun expand, larger than the orbit of the nearest planets.

But this book also connects lots of current scientific research to these stories. This is where the spirit of the analyst comes into play. For instance, the inner planets have certain ratios of crust to mantle to core while the outer bodies could be awash in oceans that are slightly sealed with solid caps. Why? The book provides some ideas but we’re still just learning to ask the questions.

The book postulates, “Why does water have different Hydrogen/Deuterium ratios throughout the solar system”. Or “What do calcium-aluminium-rich inclusions tell us about the construction of our universe”. And the book goes on to hypothesize on possible accretion processes for our solar system as based upon observations of other planetary systems. With explanations helped by current events, such as the “record of cosmogenic isotopes … that can be recovered from ice cores and tree rings” we see how the analysis extends to particulars of the heliosphere.

Be warned though, the book expects a deep level of knowledge from the reader, such as with its comparison of our Sun to the star ?⁰¹ Uma or the magnetic lineations offsets across Valles Marineris indicating crustal plate interactions. And where might all this knowledge lead the reader? Perhaps the author’s frequent allusions to abiotic and living processes, together with methods to determine the presence of life gives a clue. That is, the reader might realize just how possible yet how difficult would be to detect life elsewhere in our solar system and indeed elsewhere in the universe.

As far as writing styles, this book could be considered tight. In less than a hundred pages it covers a huge amount of the key indicators used to define our solar system. The text is heavily referenced with 20-30 for each of the 8 chapters. A sprinkling of pictures and illustrations amplify its explanations. But, as the author says, this is not a textbook of “one era after another”. Rather the author tries to link how today derives from a long ago cloud of dust which will likely lead to some very interesting times for tomorrow. And this may be indicative of what’s happening throughout the universe. As the reader will learn, humans are gaining the knowledge that can bring some order into the understanding of processes of the universe and we have only to appreciate the connections in order to heighten our understanding.

With a few billion years of formation behind it, our solar system certainly seems special. The obvious is that we know it harbours life. Us! Yet a complex web of processes and interactions bind all substances together and are the baseline to our future. Perhaps by looking at the past then we can better hypothesize what the future will hold. If you want to try this then Claudio Vita-Finzi’s book “A History of the Solar System” is a great place to get ideas and capture some of excitement of the vivacity of our life. Take if for a read and from it free up your imagination to wonder and assess where we stand in time and space.

The book is available through Springer. Learn more about the author, Claudio Vita-Finzi here.
Cheers,

October 25, 2016 by Fraser Cain

Can We Get Space Madness?

If you’ve watched any Ren and Stimpy cartoons, you know that one of the greatest hazards of spaceflight is “space madness”. Only exposure to the isolation and all pervasive radiation of deep space could drive an animated chihuahua into such a state of lunacy.

What will happen if they press the history eraser button? Maybe something good? Maybe something bad? I guess, we’ll never know.

Of course, Ren and Stimpy weren’t the first fictionalized account of people losing their marbles when they fly into the inky darkness of space. There were the Reavers from Firefly, that crazy Russian cosmonaut in Armageddon, almost everyone in the movie Sunshine, and it was the problem in every second episode of Star Trek.

The Icarus Pathfinder starship passing by Neptune. Credit: Adrian Mann

According to movies and television, if you’ve got space madness, you and your crewmates are in for a rough ride. If you’re lucky, you merely hallucinate those familiar space sirens, begging you to take off your space helmet and join them for eternity on that asteroid over there.

But you’re just as likely to go homicidal, turning on your crewmates, killing them one by one as a dark sacrifice to the black hole that powers your ship’s stardrive. And whatever you do, don’t stare too long at that pulsar, with its hypnotic, rhythmic pulse. The isolation, the alien psycho-waves, dark whisperings from eldritch gods speak to you though the paper-thin membrane of sanity. If we go to space, does only madness await us?

If you’ve spent any time around human beings, you know that we’ve got our share of mental disease right here on Earth. You don’t have to travel to space to suffer depression, anxiety, and other mental disorders.

Once we’re in orbit, or prancing about on the surface, of Mars, we’re going to experience our share of human physical and mental frailties. We’re going to take our basic humanity to space, including our brains.

According to the National Institute of Mental Health, 18% of the US population, or 40 million Americans suffer from some variety of anxiety-related disorder. 6.7% of adults had a major, crippling depressive episode over the course of a year.

Unless we improve treatment outcomes for mental disorders here on Earth, we can expect to see similar outcomes in space. Especially once we make exploration a little safer, and we’re not concerned with our immediate exposure to the vacuum of space. But will going to space make things worse?

Outside view of the Mir space station. Credit: NASA

NASA has carried out two studies on astronaut psychological health studies. One for the cosmonauts and astronauts on the Mir space station, and a second study for the folks on the International Space Station. They tested both the folks in space as well as their ground support staff once a week, to see how they were doing.

Although they reported some tension, there was no loss in mood or group cohesion during the mission. The crews had better cohesion when they had an effective leader on board.

Isolation working in close quarters has been heavily studied here on Earth, with submarine crews and isolated groups at research bases in Antarctica.

United States members of the second HI-SEAS (Hawaii Space Exploration Analog and Simulation) crew celebrate Independence Day during their simulated 120-day Mars mission. Credit: Casey Stedman/Instagram — A previous HI-SEAS simulated Mars mission. This one was only for 120 days. Credit: Casey Stedman/Instagram

Earlier this year, a crew of simulated Mars astronauts emerged, unharmed from a year-long isolation experiment in Hawaii. The six international crewmembers were part of the Hawaii Space Exploration Analog and Simulation experiment, to see what would happen to potential Mars explorers, stuff on the surface of the red planet for a year.

They couldn’t leave their 110 square-meter (1,200 square-foot) habitat without a spacesuit on. What did they report? Mostly boredom. Some interpersonal issues. Now that they’re out, some are good friends, and others probably won’t stay in contact, or pay too much attention to them in their Facebook feed.

The bottom line is that it doesn’t seem like there’s too much of a risk from the isolation and close quarters. Well, nothing that we’re not used to dealing with as human beings.

But there is another problem that has revealed itself, and might be much more severe: space dementia. And we’re not talking about the song from Muse.

According to researchers from the University of California, Irvine, long term exposure to the radiation of deep space will cause significant damage to our fragile human brains. Or at least, that’s what happened to a group of rats bathed in radiation at the NASA Space Radiation Laboratory at New York’s Brookhaven National Laboratory.

Over time, the damage to their brains would cause astronauts to experience a type of dementia that causes anxiety. Brain cancer patients who receive radiation treatment are prone to this as well.

Artist's concept of a habitat for a Mars colony. Credit: NASA — Artist’s concept of a habitat for a Mars colony. Credit: NASA

During the months and years of a Mars mission, astronauts would take a large dose of radiation, even with shielding, and the effects would be harmful to their bodies and to their brains. In fact, even when the astronauts return to Earth, their condition might worsen, with more anxiety, depression, memory problems, and a loss of decision making ability. This is a serious problem that needs to be solved if humans are going to live for a long time outside the Earth’s protective magnetosphere.

It turns out, science fiction space madness isn’t a real thing, it’s a plot device like warp drives, teleporters, and light sabers.

Isolation and close proximity isn’t much of a problem, we’ve dealt with it before, and we can still work with people, even though we hate them and the way they slurp their coffee, and lean back on their chair, even though that thing is totally going to break and they’re going to hurt themselves. And they won’t stop doing it, no matter how many times we ask them to stop.

Once again, radiation in space is a big problem. It’s out there, it’s everywhere, and we don’t have a great way to protect against it. Especially when it wrecks our brains.

October 25, 2016 by David Dickinson

Boo! A Black Moon Halloween Weekend

This Halloween weekend’s top astronomical event features something that you won’t see in the sky.

By now, you’ve probably seen the stories circulating ’round ye ole web about how this month features a ‘Black Moon.’ The internet seems to love promulgating the passing of such curious calendrical oddities as Moons both Black, Blue and otherwise.

What’s all of the hoopla about? Well, simply put, the Moon reaches New phase this weekend on October 30^th at 17:38 Universal Time (UT), marking the start of lunation 1161. This is the second New Moon for the month, as the first fell on October 1^st, just 11 minutes into the month as reckoned in Universal Time.

Now, this isn’t at all rare or unusual; the synodic period of the Moon (that is, the time it takes to return to a similar phase, such as New back to New) is 29.5 days long, a period that shoehorns well in to a 31 day month like October, or occasionally, a 30 day month.

More Fun With Calendars

February is the only month that cannot contain a ‘repeat phase,’ leap year or no. Occasionally, a given phase such as New or Full can be absent from short February all together… sometimes, this oddity is also sometimes referred to as a ‘Black Moon.’ 2014 and 2033 are the nearest years to 2016 that are missing New Moons in February.

And then there’s the relict definition of a Blue Moon as the ‘3^rd in an astronomical season with 4…‘ that can also be ascribed to a Black Moon as relates to New phase, as if we already lack enough multi-hued Moons in or lives.

Keep in mind, the moment of New is but an instant, a point a which the Moon’s longitude along the ecliptic plane equals the Sun’s. The Moon makes a miss of the Sun on most lunations, and only directly passes between the Sun and the Earth during an annular or solar eclipse. We’ve got one each coming up in 2017: an annular solar eclipse crossing the southern tip of South America on February 26^th, and the historic return of totality to the United States on August 21^st, 2017.

Said high profile solar eclipse next August also has a lesser role, as it fits that old-timey definition of the 3^rd New Moon in an astronomical season with four. Of course, this is only the juxtaposition of the lunar cycle on our current Gregorian calendar, using time reckoned in UT/GMT.

Don’t fear the Black Moon. This year’s New Moon just misses Halloween. The next New Moon on Halloween (which, of course, is always a ‘Black Moon’) occurs in 2035.

The view looking eastward on the morning of Friday, October 28th. Image credit: Stellarium

And we’ll let you in on a secret: astronomers don’t spend nights in mountaintop observatories discussing Black or Blue Moons… the term has more of an astrological tinge to it. Even in amateur astronomy circles, you sometimes hear the term ‘the dark of the Moon’ used to refer to the weeks surrounding New Moon, a prime time for deep sky astrophotography.

Looking for a New Moon-related observing challenge? Spotting the razor thin waxing or waning Moon is a fun feat of visual athletics. Look for a thin waning crescent Moon hanging near Jupiter on the morning of Friday, October 28^th. This weekend, the first shot at catching the uber-thin Moon occurs for observers along a curve from southeastern Asia at dusk on October 31^st westward at dusk. For Spain (and Astroguyz basecamp) the Moon will be 24 hours past New, and for the United States, the Moon will be 28 to 32 hours old at sunset for roaming Halloween ghouls and goblins, an easy catch.

First sighting opportunities for the waxing crescent Moon on Halloween evening. Graphic created by the author.

A time change is also afoot this weekend, as folks in Europe and the UK ‘fall back’ one hour to standard time. This setback falls nearly as late as it can in 2016, and we now enter that wacky oneeek period where the world slowly slips back to standard time. Blame ‘Big Sugar’ for the latency in most of North America, as prospective trick-or-treaters now make their rounds during daylight hours. In most of the US and Canada, the switch occurs on Sunday, November 6^th.

And there’s one more astronomical tie-in for Halloween: the holiday traces its roots back as one of the four cross-quarter days of yore, including Lammas Day, Groundhog Day, and May Day. Of course, the fixing of Hallow’s Eve on October 31^st makes the midway date only approximate: in 2016, the actual mid-point occurs on November 10^th.

Out of this world stuff to consider, as you inventory the night’s sugary bounty and contemplate the night sky.

October 24, 2016October 25, 2016 by Matt Williams

How Many Planets are There in the Galaxy?

Artist's impression of The Milky Way Galaxy. Based on current estimates and exoplanet data, it is believed that there could be tens of billions of habitable planets out there. Credit: NASA

On a clear night, and when light pollution isn’t a serious factor, looking up at the sky is a breathtaking experience. On occasions like these, it is easy to be blown away by the sheer number of stars out there. But of course, what we can see on any given night is merely a fraction of the number of stars that actually exist within our Galaxy.

What is even more astounding is the notion that the majority of these stars have their own system of planets. For some time, astronomers have believed this to be the case, and ongoing research appears to confirm it. And this naturally raises the question, just how many planets are out there? In our galaxy alone, surely, there must be billions!

Number of Planets per Star:

To truly answer that question, we need to crunch some numbers and account for some assumptions. First, despite the discovery of thousands of extra-solar planets, the Solar System is still the only one that we have studied deeply. So it could be that ours possesses more star systems than others, or that our Sun has a fraction of the planets that other stars do.

So let’s assume that the eight planets that exist within our Solar System (not taking into account Dwarf Planets, Centaurs, KBOs and other larger bodies) represent an average. The next step will be to multiply that number by the amount of stars that exist within the Milky Way.

Number of Stars:

To be clear, the actual number of stars in the Milky Way is subject to some dispute. Essentially, astronomers are forced to make estimates due to the fact that we cannot view the Milky Way from the outside. And given that the Milky Way is in the shape of a barred, spiral disc, it is difficult for us to see from one side to the other – thanks to light interference from its many stars.

As a result, estimates of how many stars there are come down to calculations of our galaxy’s mass, and estimates of how much of that mass is made up of stars. Based on these calculations, scientists estimate that the Milky Way contains between 100 and 400 billion stars (though some think there could be as many as a trillion).

Doing the math, we can then say that the Milky Way galaxy has – on average – between 800 billion and 3.2 trillion planets, with some estimates placing that number as high a 8 trillion! However, in order to determine just how many of them are habitable, we need to consider the number of exoplanets discovered so far for the sake of a sample analysis.

Habitable Exoplanets:

As of October 13th, 2016, astronomers have confirmed the presence of 3,397 exoplanets from a list of 4,696 potential candidates (which were discovered between 2009 and 2015). Some of these planets have been observed directly, in a process known as direct imaging. However, the vast majority have been detected indirectly using the radial velocity or transit method.

In the case of the former, the existence of planets is inferred based on the gravitational influence they have on their parent star. Essentially, astronomers measure how much the star moves back and forth to determine if it has a system of planets and how massive they are. In the case of the transit method, planets are detected when they pass directly in front of their star, causing it to dim. Here, size and mass are estimated based on the level of dimming.

In the course of its mission, the Kepler mission has observed about 150,000 stars, which during its initial four year mission consisted primarily of M-class stars. Also known as red dwarfs, these low-mass, lower-luminosity stars are harder to observe than our own Sun.

*Histogram showing the number of exoplanets discovered by year. Credit: NASA Ames/W. Stenzel, Princeton/T. Morton*

Since that time, Kepler has entered a new phase, also known as the K2 mission. During this phase, which began in November of 2013, Kepler has been shifting its focus to observe more in the way of K- and G-class stars – which are nearly as bright and hot as our Sun.

According to a recent study from NASA Ames Research Center, Kepler found that about 24% of M-class stars may harbor potentially habitable, Earth-size planets (i.e. those that are smaller than 1.6 times the radius of Earth’s). Based upon the number of M-class stars in the galaxy, that alone represents about 10 billion potentially habitable, Earth-like worlds.

Meanwhile, analyses of the K2 phase suggests that about one-quarter of the larger stars surveyed may also have Earth-size planet orbiting within their habitable zones. Taken together, the stars observed by Kepler make up about 70% of those found within the Milky Way. So one can estimate that there are literally tens of billions of potentially habitable planets in our galaxy alone.

In the coming years, new missions will be launching, like the James Webb Space Telescope (JWST) and the Transitting Exoplanet Survey Satellite (TESS). These missions will be able to detect smaller planets orbiting fainter stars, and maybe even determine if there’s life on any of them.

Once these new missions get going, we’ll have better estimates of the size and number of planets that orbit a typical star, and we’ll be able to come up with better estimates of just many planets there are in the galaxy. But until then, the numbers are still encouraging, as they indicate that the chances for extra-terrestrial intelligence are high!

We have written many articles about galaxies for Universe Today. Here’s How Many Stars are there in the Milky Way?, How Many Planets are there in the Solar System?, What are Extra-Solar Planets?, Planets Plentiful Around Abundant Red Dwarf Stars, Study Says, Life After Kepler: Upcoming Exoplanet Missions.

If you’d like more info on galaxies, check out Hubblesite’s News Releases on Galaxies, and here’s NASA’s Science Page on Galaxies.

We have also recorded an episode of Astronomy Cast about galaxies – Episode 97: Galaxies.

Sources:

October 24, 2016November 5, 2016 by Matt Williams

Seasonal Change On Titan Is Dynamic Business

A halo of light surrounds Saturn's moon Titan in this backlit picture, showing its atmosphere. Credit: NASA/JPL/Space Science Institute

Ever since the Cassini probe arrived at Saturn in 2004, it has revealed some startling things about the planet’s system of moons. Titan, Saturn’s largest moon, has been a particular source of fascination. Between its methane lakes, hydrocarbon-rich atmosphere, and the presence of a “methane cycle” (similar to Earth’s “water cycle”), there is no shortage of fascinating things happening on this Cronian moon.

As if that wasn’t enough, Titan also experiences seasonal changes. At present, winter is beginning in the southern hemisphere, which is characterized by the presence of a strong vortex in the upper atmosphere above the south pole. This represents a reversal of what the Cassini probe witnessed when it first started observing the moon over a decade ago, when similar things were happening in the northern hemisphere.

These finding were shared at the joint 48th meeting of the American Astronomical Society’s Division for Planetary Sciences and 11th European Planetary Science Congress, which took place from Oct 16th to 21st in Pasadena, California. As the second joint conference between these bodies, the goal of this annual meeting is to strengthen international scientific collaboration in the field of planetary science.

This cloud in the stratosphere over Titan’s north pole (left) is similar to Earth’s polar stratospheric clouds (right). NASA scientists found that Titan’s cloud contains methane ice, which was not previously thought to form in that part of the atmosphere. Cassini first spotted the cloud in 2006. Image Credit: L. NASA/JPL/U. of Ariz./LPGNantes; R. NASA/GSFC/M. Schoeberl — *The large cloud in the stratosphere over Titan’s north pole (left) is similar to Earth’s polar stratospheric clouds (right). Credit: L. NASA/JPL/U. of Ariz./LPGNantes; R. NASA/GSFC/M. Schoeberl*

During the course of the meeting, Dr. Athena Coustenis – the Director of Research (1^st class) with the National Center for Scientific Research (CNRS) in France – shared the latest atmospheric data retrieved by Cassini. As she stated:

“Cassini’s long mission and frequent visits to Titan have allowed us to observe the pattern of seasonal changes on Titan, in exquisite detail, for the first time. We arrived at the northern mid-winter and have now had the opportunity to monitor Titan’s atmospheric response through two full seasons. Since the equinox, where both hemispheres received equal heating from the Sun, we have seen rapid changes.”

Scientists have been aware of seasonal change on Titan for some time. This is characterized by warm gases rising at the summer pole and cold gases settling down at the winter pole, with heat being circulated through the atmosphere from pole to pole. This cycle experiences periodic reversals as the seasons shift from one hemisphere to the other.

In 2009, Cassini observed a large scale reversal immediately after the equinox of that year. This led to a temperature drop of about 40 °C (104 °F) around the southern polar stratosphere, while the northern hemisphere experienced gradual warming. Within months of the equinox, a trace gas vortex appeared over the south pole that showed glowing patches, while a similar feature disappeared from the north pole.

High in the atmosphere of Titan, large patches of two trace gases glow near the north pole, on the dusk side of the moon, and near the south pole, on the dawn side. Brighter colors indicate stronger signals from the two gases, HNC (left) and HC3N (right); red hues indicate less pronounced signals. Image (Credit: NRAO/AUI/NSF) — *High in the atmosphere of Titan, large patches of two trace gases glow near the north pole, on the dusk side of the moon, and near the south pole, on the dawn side. Credit: NRAO/AUI/NSF*

A reversal like this is significant because it gives astronomers a chance to study Titan’s atmosphere in greater detail. Essentially, the southern polar vortex shows concentrations of trace gases – like complex hydrocarbons, methylacetylne and benzene – which accumulate in the absence of UV light. With winter now upon the southern hemisphere, these gases can be expected to accumulate in abundance.

As Coustenis explained, this is an opportunity for planetary scientists to test out their models for Titan’s atmosphere:

“We’ve had the chance to witness the onset of winter from the beginning and are approaching the peak time for these gas-production processes in the southern hemisphere. We are now looking for new molecules in the atmosphere above Titan’s south polar region that have been predicted by our computer models. Making these detections will help us understand the photochemistry going on.”

Previously, scientists had only been able to observe these gases at high northern latitudes, which persisted well into summer. They were expected to undergo slow photochemical destruction, where exposure to light would break them down depending on their chemical makeup. However, during the past few months, a zone of depleted molecular gas and aerosols has developed at an altitude of between 400 and 500 km across the entire northern hemisphere .

View of Titan's South Pole, showing a vortex. Credit: NASA — *Titan’s south polar vortex. Credit: NASA/JPL-Caltech/Space Science Institute*

This suggests that, at high altitudes, Titan’s atmosphere has some complex dynamics going on. What these could be is not yet clear, but those who have made the study of Titan’s atmosphere a priority are eager to find out. Between now and the end of Cassini mission (which is slated for Sept. 2017), it is expected that the probe will have provided a complete picture of how Titan’s middle and upper atmospheres behave.

By mission’s end, the Cassini space probe will have conducted more than 100 targeted flybys of Saturn. In so doing, it has effectively witnessed what a full year on Titan looks like, complete with seasonal variability. Not only will this information help us to understand the deeper mysteries of one of the Solar System’s most mysterious moons, it should also come in handy if and when we send astronauts (and maybe even settlers) there someday!

Further Reading: Europlanet

October 23, 2016October 23, 2016 by Matt Williams

What are Molecules?

For millennia, scientists have pondered the mystery of life – namely, what goes into making it? According to most ancient cultures, life and all existence was made up of the basic elements of nature – i.e. Earth, Air, Wind, Water, and Fire. However, in time, many philosophers began to put forth the notion that all things were composed of tiny, indivisible things that could neither be created nor destroyed (i.e. particles).

However, this was a largely philosophical notion, and it was not until the emergence of atomic theory and modern chemistry that scientists began to postulate that particles, when taken in combination, produced the basic building blocks of all things. Molecules, they called them, taken from the Latin “moles” (which means “mass” or “barrier”). But used in the context of modern particle theory, the term refers to small units of mass.

Definition:

By its classical definition, a molecule is the smallest particle of a substance that retains the chemical and physical properties of that substance. They are composed of two or more atoms, a group of like or different atoms held together by chemical forces.

Both simple and complex organic (carbon-containing) molecules have been found in space. Carbon is formed in the cores of red giant stars, where it gets cycled to the surface and dispensed into space. Credit: IAC; original image of the Helix Nebula (NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner, STScI, & T.A. Rector, NRAO — *Artist’s impression of simple and complex organic (carbon-containing) molecules that have been found in space. Credit: IAC/NASA/NOAO/ESA/Hubble Helix Nebula Team/M. Meixner/STScI/T.A. Rector/NRAO*

It may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O). As components of matter, molecules are common in organic substances (and therefore biochemistry) and are what allow for life-giving elements, like liquid water and breathable atmospheres.

Types of Bonds:

Molecules are held together by one of two types of bonds – covalent bonds or ionic bonds. A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. And the bond they form, which is the result of a stable balance of attractive and repulsive forces between atoms, is known as covalent bonding.

Ionic bonding, by contrast, is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions. The ions involved in this kind of bond are atoms that have lost one or more electrons (called cations), and those that have gained one or more electrons (called anions). In contrast to covalence, this transfer is termed electrovalance.

In the simplest of forms, covelant bonds take place between a metal atom (as the cation) and a nonmetal atom (the anion), leading to compounds like Sodium Chloride (NaCl) or Iron Oxide (Fe²O³) – aka. salt and rust. However, more complex arrangements can be made too, such as ammonium (NH⁴⁺) or hydrocarbons like methane (CH⁴) and ethane (H³CCH³).

*Diagram of a water molecule, which is made up of two hydrogen atoms and one oxygen atom. Credit: britannica.com*

History of Study

Historically, molecular theory and atomic theory are intertwined. The first recorded mention of matter being made up of “discreet units” began in ancient India where practitioners of Jainism espoused the notion that all things were composed of small indivisible elements that combined to form more complex objects.

In ancient Greece, philosophers Leucippus and Democritus coined the term “atomos” when referring to the “smallest indivisible parts of matter”, from which we derive the modern term atom.

Then in 1661, naturalist Robert Boyle argued in a treatise on chemistry – titled “The Sceptical Chymist“- that matter was composed of various combinations of “corpuscules”, rather than earth, air, wind, water and fire. However. these observations were confined to the field of philosophy.

It was not until the late 18th and early 19th century when Antoine Lavoisier’s Law of Conservation of Mass and Dalton’s Law of Multiple Proportions brought atoms and molecules into the field of hard science. The former proposed that elements are basic substances that cannot be broken down further while the latter proposed that each element consists of a single, unique type, of atom and that these can join together to form chemical compounds.

Various atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy (1808). Credit: Public Domain — *Various atoms and molecules as depicted in John Dalton’s A New System of Chemical Philosophy (1808). Credit: Public Domain*

A further boon came in 1865 when Johann Josef Loschmidt measured the size of the molecules that make up air, thus giving a sense of scale to molecules. The invention of the Scanning Tunneling Microscope (STM) in 1981 allowed for atoms and molecules to be observed directly for the first time as well.

Today, our concept of molecules is being refined further thanks to ongoing research in the fields of quantum physics, organic chemistry and biochemistry. And when it comes to the search for life on other worlds, an understanding of what organic molecules need in order to emerge from the combination of chemical building blocks, is essential.

We have written many interesting articles about molecules for Universe Today. Here’s Molecules From Space May Have Affected Life On Earth, Prebiotic Molecules May Form in Exoplanet Atmospheres, Organic Molecules Found Outside our Solar System, ‘Ultimate’ Prebiotic Molecules Found in Interstellar Space.

For more information, check out Encyclopaedia Britannica‘s page on molecules.

We’ve also recorded an entire episode of Astronomy Cast all about Molecules in Space. Listen here, Episode 116: Molecules in Space.

Sources:

October 23, 2016October 23, 2016 by Ken Kremer

First Cygnus Cargo Ship from Virginia in Two Years Docks at Space Station

Installation complete! Orbital ATK's Cygnus cargo spacecraft was attached to the International Space_Station at 10:53 a.m. EDT on 23 Oct. 2016 after launching atop Antares rocket on 17 Oct. 2016 from NASA Wallops in Virginia. Credit: NASA

After a two year gap, the first Cygnus cargo freight train from Virginia bound for the International Space Station (ISS) arrived earlier this morning – restoring this critical supply route to full operation today, Sunday, Oct. 23.

The Orbital ATK Cygnus cargo spacecraft packed with over 2.5 tons of supplies was berthed to an Earth-facing port on the Unity module of the ISS at 10:53 a.m. EDT.

The Cygnus OA-5 resupply ship slowly approaches the space station before the Canadarm2 reaches out and grapples it on Oct. 23, 2016. Credit: NASA TV

The Cygnus OA-5 mission took flight atop the first re-engined Orbital ATK Antares rocket during a spectacular Monday night liftoff on Oct. 17 at 7:40 p.m. EDT from the Mid-Atlantic Regional Spaceport pad 0A at NASA’s Wallops Flight Facility on Virginia’s picturesque Eastern shore.

Antares pair of RD-181 first stage engines were firing with some 1.2 million pounds of liftoff thrust and brilliantly lighting up the crystal clear evening skies in every direction to the delight of hordes of spectators gathered from near and far.

The Orbital ATK Antares rocket topped with the Cygnus cargo spacecraft launches from Pad-0A, Monday, Oct. 17, 2016 at NASA’s Wallops Flight Facility in Virginia. Orbital ATK’s sixth contracted cargo resupply mission with NASA to the International Space Station. Credit: Ken Kremer/kenkremer

Cygnus is loaded with over 5,100 pounds of science investigations, food, supplies and hardware for the space station and its six-person multinational crew.

This was the first Antares launch from Virginia in two years following the rockets catastrophic failure just moments after liftoff on Oct. 28, 2014, which doomed the Orb-3 resupply mission to the space station – as witnessed by this author.

Orbital ATK’s Antares commercial rocket had to be overhauled with the completely new RD-181 first stage engines- fueled by LOX/kerosene – following the destruction of the Antares rocket and Cygnus supply ship two years ago.

The 14 story tall commercial Antares rocket launched for the first time in the upgraded 230 configuration – powered by a pair of the new Russian-built RD-181 first stage engines.

The RD-181 replaces the previously used AJ26 engines which failed shortly after the last liftoff on Oct. 28, 2014 and destroyed the rocket and Cygnus cargo freighter.

The launch mishap was traced to a failure in the AJ26 first stage engine turbopump and forced Antares launches to immediately grind to a halt.

After a carefully choreographed five day orbital chase, Cygnus approached the million pound orbiting outpost this morning.

After it was within reach, Expedition 49 Flight Engineers Takuya Onishi of the Japan Aerospace Exploration Agency and Kate Rubins of NASA carefully maneuvered the station’s 57.7-foot (17.6-meter) Canadian-built robotic arm to reach out and capture the Cygnus OA-5 spacecraft at 7:28 a.m. EDT.

It was approximately 30 feet (10 meters) away from the station as Onishi and Rubins grappled the resupply ship with the robotic arms snares.

Today’s installation of the Orbital ATK Cygnus OA-5 resupply ship makes four spaceships attached to the International Space Station on 23 October 2016. Credit: NASA

After leak checks, the next step is for the crew to open the hatches between the pressurized Cygnus and Unity and begin unloading the stash aboard.

The 21-foot-long (6.4-meter) spacecraft is scheduled to spend about five weeks attached to the station. The crew will pack the ship with trash and no longer needed supplies and gear.

It will be undocked in November and then conduct several science experiments, including the Saffire fire experiment and deploy cubesats.

Thereafter it will be commanded to conduct the customary destructive re-entry in Earth’s atmosphere.

Cygnus cargo spacecraft atop Orbital ATK Antares rocket on Pad-0A prior to blastoff on Oct. 17, 2016 from NASA’s Wallops Flight Facility in Virginia on Orbital ATK’s sixth contracted cargo resupply mission with NASA to the International Space Station. Credit: Ken Kremer/kenkremer

The Cygnus spacecraft for the OA-5 mission is named the S.S. Alan G. Poindexter in honor of former astronaut and Naval Aviator Captain Alan Poindexter.

Under the Commercial Resupply Services (CRS) contract with NASA, Orbital ATK will deliver approximately 28,700 kilograms of cargo to the space station. OA-5 is the sixth of these missions.

Antares launch on Oct. 17, 2016 from NASA's Wallops Flight Facility in Virginia. Credit: © Patrick J. Hendrickson / Highcamera.com — Antares launch on Oct. 17, 2016 from NASA’s Wallops Flight Facility in Virginia. Credit: © Patrick J. Hendrickson / Highcamera.com

Watch for Ken’s continuing Antares/Cygnus mission and launch reporting. He was reporting from on site at NASA’s Wallops Flight Facility, VA during the launch campaign.

On-Ramp to the International Space Station (ISS) with Orbital ATL Antares rocket and Cygnus cargo freighter which launched on 17 Oct. 2016 and berthed at the Unity docking port on 23 Oct. 2016. Credit: Ken Kremer/kenkremer

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer