Space and astronomy news
It turns out that nature figured out how to use electricity long before humans did. Lightning storms are common across the Earth, and even the Solar System. What causes this electricity in the sky, and how can science use it?
Visit the Astronomy Cast Page to subscribe to the audio podcast!
We usually record Astronomy Cast as a live Google+ Hangout on Air every Friday at 1:30 pm Pacific / 4:30 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.
Watch how Schiaparelli will land on Mars. Touchdown will occur at 10:48 a.m. EDT (14:48 GMT) Wednesday Oct. 19.
Cross your fingers for good weather on the Red Planet on October 19. That’s the day the European Space Agency’s Schiaparelli lander pops open its parachute, fires nine, liquid-fueled thrusters and descends to the surface of Mars. Assuming fair weather, the lander should settle down safely on the wide-open plains of Meridiani Planum near the Martian equator northwest of NASA’s Opportunity rover. The region is rich in hematite, an iron-rich mineral associated with hot springs here on Earth.
The 8-foot-wide probe will be released three days earlier from the Trace Gas Orbiter (TGO) and coast toward Mars before entering its atmosphere at 13,000 mph (21,000 km/hr). During the 6-minute-long descent, Schiaparelli will decelerate gradually using the atmosphere to brake its speed, a technique called aerobraking. Not only is Meridiani Planum flat, it’s low, which means the atmosphere is thick enough to allow Schiaparelli’s heat shield to reduce its speed sufficiently so the chute can be safely deployed. The final firing of its thrusters will ensure a soft and controlled landing.
The lander is one-half of the ExoMars 2016 mission, a joint venture between the European Space Agency and Russia’s Roscosmos. The Trace Gas Orbiter (TGO) will fire its thrusters to place itself in orbit about the Red Planet the same day Schiparelli lands. Its job is to inventory the atmosphere in search of organic molecules, methane in particular. Plumes of methane, which may be biological or geological (or both) in origin, have recently been detected at several locations on Mars including Syrtis Major, the planet’s most prominent dark marking. The orbiter will hopefully pinpoint the source(s) as well as study seasonal changes in locations and concentrations.
Methane (CH4) has long been associated with life here on Earth. More than 90% of the colorless, odorless gas is produced by living organisms, primarily bacteria. Sunlight breaks methane down into other gases over a span of about 300 years. Because the gas relatively short-lived, seeing it on Mars implies an active, current source. There may be several:
Will it turn out to be burping bacteria or mineral processes? Let’s hope TGO can point the way.
The Trace Gas Orbiter will also use the Martian atmosphere to slow its speed and trim its orbital loop into a 248-mile-high (400 km) circle suitable for science observations. But don’t expect much in the way of scientific results right away; aerobraking maneuvers will take about a year, so TGO’s job of teasing out atmospheric ingredients won’t begin until December 2017. The study runs for 5 years.
The orbiter will also examine Martian water vapor, nitrogen oxides and other organics with far greater accuracy than any previous probe as well as monitor seasonal changes in the atmosphere’s composition and temperature. And get this — its instruments can map subsurface hydrogen, a key ingredient in both water and methane, down to a depth of a meter (39.4 inches) with greater resolution compared to previous studies. Who knows? We may discover hidden ice deposits or methane sinks that could influence where future rovers will land. Additional missions to Mars are already on the docket, including ExoMars 2020. More about that in a minute.
While TGO’s mission will require years, the lander is expected to survive for only four Martian days (called ‘sols’) by using the excess energy capacity of its batteries. A set of scientific sensors will measure wind speed and direction, humidity, pressure and electric fields on the surface. A descent camera will take pictures of the landing site on the way down; we’ll should see those photos the very next day. Data and imagery from the lander will be transmitted to ESA’s Mars Express and a NASA Relay Orbiter, then relayed to Earth.
This animation shows the paths of the Trace Gas Orbiter and Schiaparelli lander on Oct. 19 when they arrive at Mars.
If you’re wondering why the lander’s mission is so brief, it’s because Schiaparelli is essentially a test vehicle. Its primary purpose is to test technologies for landing on Mars including the special materials used for protection against the heat of entry, a parachute system, a Doppler radar device for measuring altitude and liquid-fueled braking thrusters.
Martian dust storms can be cause for concern during any landing attempt. Since it’s now autumn in the planet’s northern hemisphere, a time when storms are common, there’s been some finger-nail biting of late. The good news is that storms of recent weeks have calmed and Mars has entered a welcome quiet spell.
To watch events unfold in real time, check out ESA’s live stream channel, Facebook page and Twitter updates. The announcement of the separation of the lander from the orbiter will be made around 11 a.m. Eastern Time (15:00 GMT) Sunday October 16. Live coverage of the Trace Gas Orbiter arrival and Schiaparelli landing on Mars runs from 9-11:15 a.m. Eastern (13:00-15:15 GMT) on Wednesday October 19. Photos taken by Schiaparelli’s descent camera will be available starting at 4 a.m. Eastern (8:00 GMT) on October 20. More details here. We’ll also keep you updated on Universe Today.
Everything we learn during the current mission will be applied to planning and executing the next — ExoMars 2020, slated to launch in 2020. That venture will send a rover to the surface to search and chemically test for signs of life, present or past. It will collect samples with a drill at various depths and analyze the fines for bio-molecules. Getting down deep is important because the planet’s thin atmosphere lets through harsh UV light from the sun, sterilizing the surface.
Are you ready for adventure? See you on Mars (vicariously)!
Back in 2007, astronomers observed a series of unusual eclipses coming from a star 420 light years from Earth. In 2012, a team from Japan and the Netherlands reasoned that this phenomena was due to the presence of a large exoplanet – designated J1407b – with a massive ring system orbiting the star. Since then, several surprising finds have been made.
For example, in 2015, the same team concluded that the ring system is one-hundred times larger and heavier than Saturn’s (and may be similarly sculpted by exomoons). And in their most recent study, they have shown that these giant rings may last for over 100,000 years, assuming they have a rare and unusual orbit around their planet.
In their previous work, Rieder and Kenworth determined that the ring system around J1407b consisted about 37 rings that extend to a distance of 0.6 AU (90 million km) from the planet. They also estimated that these rings are 100 times as massive as our Moon – 7342 trillion trillion metric tons. What’s more, while J1407b’s existence is yet to be confirmed, they were able to rule out the possibility of it having a circular orbit around the star.
As a result, there were doubts that such a ring system could exist. Given the fact that the planet periodically gets closer to its star, the ring system would experience gravitational disruption. Therefore, Steven Rieder (of the RIKEN institute in Japan) and Matthew Kenworth (of Leiden University in the Netherlands) set out to assess how long such a ring system could remain stable for.
For the sake of their study, titled “Constraints on the Size and Dynamics of the J1407b Ring System“, they conducted a series of simulations using the Astrophysical Multi-purpose Software Environment (AMUSE) framework. In the end, their results showed that a ring structure with an 11 year orbital period and a retrograde orbit could survive for at least 10,000 orbits.
In other words, the ring system that they hypothesized back in 2012 could endure for 110,000 years. As Rieder (the lead author on the paper) explained in a statement, the results were surprising, but happened to fit the facts:
“The system is only stable when the rings rotate opposite to how the planet orbits the star. It might be far-fetched: massive rings that rotate in opposite direction, but we now have calculated that a ‘normal’ ring system cannot survive.”
How such a ring system could have come about is a mystery, as retrograde ring systems are quite uncommon. But Rieder and Kenworth have stated that they think it might be the result of a catastrophic event – such as a massive collision – that caused the rings (or the planet) to change the direction of their rotation.
Their results also indicated that a retrograde ring system would allow for eclipses, like the one that was observed in 2007. While there was some chance of these being caused by another object, the results suggested otherwise. “The chance of that is minimal,” said Rieder. “Also, the velocity measured with previous observations may not be right, but that would be very strange, because those measurements are very accurate.”
In the future, Rieder and Kenswoth hope to investigate the mysteries of this ring formation more closely. This will include how it could have formed in the first place, and how it has evolved over time. Their study has been accepted for publication in the journal Astronomy & Astrophysics and be viewed online at arXiv.
Further Reading: astronomie.nl, arXiv
A gigantic piece of the famous Campo del Cielo meteorite fall that was found on September 10, 2016 has been un-earthed, and is now on display in Gancedo, Chaco, Argentina. Photographer Pelin Rodriguez shared some images with Universe Today that he took of the newly found behemoth during a recent “Celebration of the Meteorite.”
And in a surprise finding during a weigh-in of both the new Gancedo meteorite and another meteorite named el Chaco that what was thought to be the biggest meteorite from the Campo del Cielo site, the Gancedo meteorite may actually be bigger. El Chaco was originally billed as 37 tons, but a recent tip of the scales put el Chaco at only 28 tons. Rodriguez said both meteorites will be weighed again in order to verify the tonnage. If confirmed, that would make the Gancedo meteorite the second largest meteorite chunk in the world after the 66-ton Hoba meteorite discovered in Namibia, Africa.
Rodriguez said the Gancedo meteorite contains many colors ranging from red, yellow, green, white and different shades of brown.
Scientists estimate about 4,500 years ago, a 600 ton space rock entered Earth’s atmosphere and broke apart, sending a shower of metallic meteorites across a 1,350 square km region northwest of Buenos Aires. The region has at least 26 craters, with the largest crater being about 100 meters wide. The AstronoR group said that the Gancedo meteorite was buried only 3 meters deep.
Rodriguez is a member of the AstronoR astronomy group in Argentina that held a two-day astronomy outreach event at the Village of Gancedo, located 312 km from Resistencia, the capital city of Chaco.
Thanks to Pelin Rodriguez for sharing his images with Universe Today. You can see some additional photos and videos from the event on the AstronoR Facebook page.
I seem like a pretty calm and collected guy, but if you want to see me go on an epic rant, all you have to do is ask me some variation on the question: “why should we bother exploring space when we’ve got problems to fix here on Earth.”
I see this question all the time. All the time, in forums, comments on videos, and from people in audiences.
I think the question is ridiculous on many levels, and I’ve got a bunch of reasons why, but allow me to explain them here.
Before I do, however, I want you to understand that I believe that we human beings are indeed messing up the environment. We’re wiping out species faster than any natural disaster in the history of planet Earth. We’re performing a dangerous experiment on the climate of the planet, increasing temperatures worldwide, with devastating consequences, for both ecosystems and human civilization.
Unless we get this under control, and there’s no reason to believe we will, we’re going to raise temperatures to levels unseen in millions of years.
There are islands of plastic garbage in the oceans, collected into huge toxic rafts by the currents. Colonies of bees are dying through pesticides and habitat loss.
We’re even polluting the space around the Earth with debris that might tear apart future space missions.
I believe the science, and the science says we’re making a mess.
The first thing is that this whole question is a false dilemma fallacy. Why do we have to choose between space exploration and saving the planet? Why can’t we do both?
The world spent nearly $750 billion on cigarettes in 2014. NASA’s total budget is less than $20 billion, and Elon Musk thinks he can start sending colonists to Mars for less than $10 billion.
How about the whole world stops smoking, and we spend $20 billion on colonizing Mars and the other $730 billion on renewable fuels and cleaning up our negative impact on the environment, reducing poverty and giving people access to clean water?
Americans spend $27 billion on takeout pizza. Don’t get me wrong, pizza’s great, but I’d be willing to forego pizza if it meant a vibrant and healthy industry of space exploration.
Gambling, lawn care, hood ornaments, weapons of war. Humans spend a lot of money on a lot of things that could be redirected towards both space exploration and reducing our environmental impact.
Number two, it might turn out that space exploration is the best way to save the Earth. I totally agree with Blue Origin’s Jeff Bezos when he says that we already know that Earth is the best place in the Solar System. Let’s keep it that way.
Mars might be a fascinating place to visit and an adventure to colonize, but I want to swim in rivers, climb mountains, walk in forests, watch birds, sail in the ocean.
But the way we’re using up the natural environment will take away from all that. As Bezos says, we should move all the heavy industry off Earth and up into space. Use solar collectors to gather power, mine asteroids for their raw materials. Keep Earth as pristine as possible.
We won’t know how to do that unless we actually go into space and learn how to survive and run that industry, from space.
Number three, it might be that we’ve already crossed the point of no return. There’s a great science fiction story by Spider Robinson called “In the Olden Days”. It’s about how modern society turned its back on technology, and lost the ability to ever recover.
Humanity used up the entire technology ladder that nature put in front of us; the chunks of iron just sitting on the ground, the oil bubbling out of the Earth, the coal that was easily accessible. Now it takes an offshore drilling rig to get at the oil.
These resources took the Earth millions and even billions of years to accumulate for us to use, and transcend. When the cockroaches evolve intelligence and opposable thumbs, they won’t have those easily accessible resources to jumpstart their own space exploration program.
Number four, as Elon Musk says, we have to protect the cradle of consciousness. Until we find proof otherwise, we have to assume that the Earth is the only place in the Universe that evolved intelligent life.
And until the alien overlords show up and say, “don’t worry humans, we’ve got this,” we have to assume that the responsibility for seeding the life with intelligence rests on us. And we’re one asteroid strike or nuclear apocalypse away from snuffing that out.
I don’t entirely agree that Mars is the best place to do it, but we should at least have another party going on somewhere.
And number five, it’ll be fun. Humans need adventure. We need great challenges to push us to become the best versions of ourselves. We climb mountains because they’re there.
Ask anyone who’s built their own house or tried their hand at homesteading. It’s a tremendous amount of work, but it’s also rewarding in ways that buying stuff just isn’t.
The next time someone uses that argument on you, I hope this gives you some ammunition.
Phew, now I’ll get off my soapbox. Next week, I’m sure we’ll return to poop jokes, obscure science fiction references with a smattering of space science.
This week’s Carnival of Space is hosted by Brian Wang at his Next Big Future blog.
Click here to read Carnival of Space #478
Continue reading “Carnival of Space #478”
Ready for some lunar action of proxigean proportions? This weekend’s Full Moon ushers in that most (infamous?) of internet ready cultural memes: that of the Supermoon. This moniker stands above the Blood, Mini, and Full Moons both Black and Blue as the Full Moon of the year that folks can’t seem to get enough of, and astronomers love to hate.
But wait a minute: is this weekend’s Full Moon really the closest of the year?
Nope, though it’s close. But this month’s Full Moon does, however, usher in what we like to call Supermoon season.
Let us explain.
First, we’ll let you in on the Supermoon’s not so secret history. Yes, the meme arose over the last few decades, mostly due to the dastardly deeds of astrologers. Y’know, that well meaning friend/coworker/relative/anonymous person on Twitter that constantly mistakes your passion for the night sky as ‘astrology.’ Anyhow, the idea of the Supermoon has gained new life via the internet, and loosely translates as the closest Full Moon of the year. Sometimes, its dressed up with the slightly science-y sounding ‘a Full Moon along the closest 90% of its orbit’ (!) definition.
Now, to know the orbit of the Moon is to understand celestial mechanics. The Moon’s orbit is indeed elliptical, ranging from an average perigee (its closest point to the Earth) of 362,600 kilometers, to an apogee of 405,400 kilometers distant.
Fun fact: the time it takes the Moon to go from one perigee to the next (27.55 days) is one anomalistic month, a fine pedantic point to bring up to said relative/coworker the next time they refer to you as an astrologer.
And yes, the perigee Full Moon is a thing. We even like to throw about the quixotic term of the proxigean Moon, a time when tidal variations are at an extreme. Plus, all perigees are not created equal, but range from 356,400 kilometers to 370,400 kilometers distant, as the Earth-Moon system not only swings around its common barycenter, but the Sun also drags the entire orbit of the Moon around the Earth, completing one complete revolution every 8.85 years in what’s known as the precession of the line of apsides. Note that the nodes of the Moon’s orbit actually move in the opposite direction, with an 18.6 year period.
Yup, the motion of the Moon has given humanity a fine study in Celestial Mechanics 101. Anyhow, we contend that a more succinct definition for a perigee ‘Supermoon’ is simply a Full Moon that falls within 24 hours of perigee. Under this definition, the Full Moon this Sunday on October 16th occurring at 4:23 Universal Time (UT) certainly meets the criterion, occurring 19 hours and 24 minutes before perigee… as does the Full Moon of November 14th (2.4 hours from perigee) and December 13th (just under 24 hours from perigee).
For extra fun, said November 14th perigee Full Moon is the closest in 30 years; expect Supermoon lunacy to ensue.
A fun place to play with Full and New Moons vs perigee and apogee past present and future is Fourmilab’s Lunar Apogee and Perigee Calculator. Hey, it’s what we do for fun. Looking over these cycles, you’ll notice a pattern of ‘supermoon seasons’ emerge, which moves forward along the calendar about a lunation a year. (that’s our friend the precession of the line of apsides at work again).
(another fun fact: the time it takes for the Moon to return to a similar phase—for example, Full back to Full—is 29.5 days, and known as a synodic month.)
The Full Moon does appear slightly larger at perigee than apogee, to the tune of 29.3′ versus 34.1′ across. This change is enough to notice with the unaided eye, though the Moon is deceptively smaller than it appears: you could, for example, line up 654 ‘Supermoons’ around the local horizon from end to end.
The October Moon is also referred to by the Algonquin Native Americans as the ‘Hunter’s Moon,’ a time to use that extra illumination to track down vital sustenance as the harsh winter approaches. Very occasionally, the Harvest Full Moon falling near the September southward equinox falls in early October (as occurs next year in 2017) and bumps the Hunter’s Moon from its monthly slot.
Be sure to stalk the rising Hunter’s Moon near perigee this weekend. Of course, we’ll be shooting at our prey with nothing more than a camera, as the Full Moon rises from behind the Andalusian foothills.
The longest living Martian rover ever – Opportunity – has just surpassed another unfathomable milestone – 4500 Sols (or days) exploring the Red Planet !! That’s 50 times beyond her “warrantied” life expectancy of merely 90 Sols.
And as we are fond of reporting – the best is yet to come. After experiencing 4500 Martian sunsets, Opportunity has been granted another mission extension and she is being targeted to drive to an ancient gully where life giving liquid water almost certainly once flowed on our solar systems most Earth-like planet.
See Opportunity’s current location around ‘Spirit Mound” – illustrated in our new photo mosaic panoramas above and below.
After a scorching ‘6 minutes of Terror’ plummet through the thin Martian atmosphere, Opportunity bounced to an airbag cushioned landing on the plains of Meridiani Planum on January 24, 2004 – nearly 13 years ago!
Opportunity was launched on a Delta II rocket from Cape Canaveral Air Force Station in Florida on July 7, 2003.
“We have now exceeded the prime-mission duration by a factor of 50,” noted Opportunity Project Manager John Callas of NASA’s Jet Propulsion Laboratory, Pasadena, California.
“Milestones like this are reminders of the historic achievements made possible by the dedicated people entrusted to build and operate this national asset for exploring Mars.”
The newest 2 year extended mission phase just began on Oct. 1 as the rover was stationed at the western rim of Endeavour crater at the bottom of Marathon Valley at a spot called “Bitterroot Valley.”
And at this moment, as Opportunity reached and surpassed the 4500 Sol milestone, she is investing an majestic spot dubbed “Spirit Mound” – and named after her twin sister “Spirit” – who landed 3 weeks earlier!
Endeavour crater spans some 22 kilometers (14 miles) in diameter. Opportunity has been exploring Endeavour since arriving at the humongous crater in 2011.
Endeavour crater was formed when it was carved out of the Red Planet by a huge meteor impact billions of years ago.
But now for the first time she will explore the craters interior, after spending 5 years investigating the exterior and climbing to a summit on the rim and spending several year exploring the top before finally descending down the Marathon Valley feature to investigate clay minerals formed in water.
“The longest-active rover on Mars also will, for the first time, visit the interior of the crater it has worked beside for the last five years,” said NASA officials.
Marathon Valley measures about 300 yards or meters long. It cuts downhill through the west rim of Endeavour crater from west to east – the same direction in which Opportunity drove downhill from a mountain summit area atop the crater rim. See our route map below showing the context of the rovers over dozen year long traverse spanning more than the 26 mile distance of a Marathon runners race.
Opportunity is now being targeted to explore a gully carved out by water.
“We are confident this is a fluid-carved gully, and that water was involved,” said Opportunity Principal Investigator Steve Squyres of Cornell University, Ithaca, New York.
“Fluid-carved gullies on Mars have been seen from orbit since the 1970s, but none had been examined up close on the surface before. One of the three main objectives of our new mission extension is to investigate this gully. We hope to learn whether the fluid was a debris flow, with lots of rubble lubricated by water, or a flow with mostly water and less other material.”
Furthermore, in what’s a very exciting announcement the team “intends to drive Opportunity down the full length of the gully, onto the crater floor” – if the rover continues to function well during the two year extended mission which will have to include enduring her 8th frigid Martian winter in 2017.
And as is always the case, scientists will compare these interior crater rocks to those on the exterior for clues into the evolution, environmental and climatic history of Mars over billions of years.
“We may find that the sulfate-rich rocks we’ve seen outside the crater are not the same inside,” Squyres said. “We believe these sulfate-rich rocks formed from a water-related process, and water flows downhill. The watery environment deep inside the crater may have been different from outside on the plain — maybe different timing, maybe different chemistry.”
As of today, Sol 4522, Oct 12, 2016, Opportunity has taken over 214,400 images and traversed over 26.99 miles (43.44 kilometers) – more than a marathon.
The power output from solar array energy production is currently 472 watt-hours, before heading into another southern hemisphere Martian winter in 2017.
Meanwhile Opportunity’s younger sister rover Curiosity traverses and drills into the basal layers at the base of Mount Sharp.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
The Kuiper Belt has been an endless source of discoveries over the course of the past decade. Starting with the dwarf planet Eris, which was first observed by a Palomar Observatory survey led by Mike Brown in 2003, many interesting Kuiper Belt Objects (KBOs) have been discovered, some of which are comparable in size to Pluto.
And according to a new report from the IAU Minor Planet Center, yet another body has been discovered beyond the orbit of Pluto. Officially designated as 2014 UZ224, this body is located about 14 billion km (90 AUs, or 8.5 billion miles) from the Sun. This dwarf planet is not only the latest member of the our Solar family, it is also the second-farthest body from our Sun with a stable orbit.
The discovery was made by David Gerdes, a professor of astrophysics at the University of Michigan, and various colleagues associated with at the Dark Energy Survey (DES) – a project which relies on the Cerro Tololo Inter-American Observatory in Chile. In the past, Gerdes’ research has focused on the detection of dark energy and the expansion of the Universe.
Towards this end, DES has spent the past five years surveying roughly one-eighth of the sky using the Dark Energy Camera (DECam), a 570-Megapixel camera mounted on the Victor M. Blanco telescope at Cerro Tololo. This instrument was commissioned by the US. Dept of Energy to conduct surveys of distant galaxies, and Dr. Gerdes had a hand in creating.
Not surprisingly, this same technology has also allowed for discoveries to be made at the edge of the Solar System. Two years ago, this is precisely what Gerdes challenged a group of undergraduate students to do (as part of a summer project). These students examined images taken by DES between 2013-2016 for indications of moving objects. Since that time, the analysis team has grown to include senior scientists, postdocs, graduate and undergraduate students.
Whereas distant stars and galaxies would appear stationary in these images, distant TNOs showed up in different places over time – hence why are called “transients”. As Dr. Gerdes explains in his 2014 UZ224 Fact Sheet, which is available through his University of Michigan homepage:
“To identify transients, we used a technique known as “difference imaging”. When we take a new image, we subtract from it an image of the same area of the sky taken on a different night. Objects that don’t change disappear in this subtraction, and we’re left with only the transients… This process yields millions of transients, but only about 0.1% of them turn out to be distant minor planets. To find them, we must “connect the dots” and determine which transients are actually the same thing in different positions on different nights. There are many dots and MANY more possible ways to connect them.”
This was a difficult process. In addition to needing thousands of computers at Fermilab to process the hundreds of terabytes of data, the team had to write special programs to do it. Gerdes and his colleagues also relied on help from Professors Masao Sako and Gary Bernstein of the University of Pennsylvania, who contributed the key breakthroughs that allowed them to perform difference imaging over the entire survey area.
In the end, dozens of new Trans-Neptunian Objects (TNOs) were discovered, one of which was 2014 UZ224. According to their observations, its diameter could be anywhere from 350 to 1200 km, and it takes 1,136 years to complete a single orbit of our Sun. For the sake of perspective, Pluto is 2370 km in diameter, and has an orbital period of 248 years.
Stephanie Hamilton, a graduate student at the University of Michigan, was personally involved with the project. Her role was to determine the size of 2014 UZ224, which was difficult from initial observations alone. As she told Universe Today via email:
“The object’s brightness in visible light alone depends both on its size and how reflective it is, so you can’t uniquely determine one of those properties without assuming a value for the other. Fortunately there’s a solution to that problem – the heat the object emits is also proportional to its size, so obtaining a thermal measurement in addition to the optical measurements means we would then be able to calculate the object’s size and albedo (reflectance) without having to assume one or the other.
“We were able to obtain an image of our object at a thermal wavelength using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. I am working on combining all of our data together to determine the size and albedo, and we expect to submit a paper on our results around mid-November or so.”
But as with all things related to “dwarf planets”, there has been some disagreement over this discovery. Given the dimensions of the object, there are some who question whether or not the label applies. But as Gerdes indicates on the Fact Sheet, this body fits most of the prerequisites:
“According to the official IAU guidelines, a dwarf planet must satisfy four criteria. It must a) orbit the sun (check!), b) not be a satellite (check!) c) not have cleared the neighborhood around its orbit (check!) and d) have enough mass to be round. It’s this last item that’s uncertain, and the only way for sure is to get a picture that’s detailed enough to actually see its shape. Nevertheless, an object over 400 km in diameter is likely to be round.”
Gerdes and his team expect to be busy, authoring the paper that will detail their findings, using the ALMA array to get more assessments of 2014 UZ224 size, and sifting through the data to look for more objects in the Kuiper Belt. This includes the fabled Planet 9, which astronomers have been seeking out for years.
Given its distance from the Sun, 2014 UZ224’s orbit would not be influenced by the presence of Planet 9, and is therefore of no help. However, Gerdes is optimistic that the evidence of this massive body is there in the data. Given time, and a lot of data-processing, they just might find it! In the meantime, this newly discovered object is likely to be the focal point of a lot of fascinating research.
“It’s an interesting object in its own right – distant objects like this are ‘cosmic leftovers’ from the primordial disk that gave birth to the solar system,” writes Gerdes. “By studying them and learning more about their distribution, orbital characteristics, sizes, and surface properties, we can learn more about the processes that gave birth to the solar system and ultimately to us.”
Further Reading: 2014 UZ224 Fact Sheet (University of Michigan)
In August of 2016, the European Southern Observatory announced that the nearest star to our own – Proxima Centauri – had an exoplanet. Since that time, considerable attention has been focused on this world (Proxima b) in the hopes of determining just how “Earth-like” it really is. Despite all indications of it being terrestrial and similar in mass to Earth, there are some lingering doubts about its ability to support life.
This is largely due to the fact that Proxima b orbits a red dwarf. Typically, these low mass, low temperature, slow fusion stars are not known for being as bright and warm as our Sun. However, a new study produced by researchers at the Harvard Smithsonian Center for Astrophysics (CfA) has indicated that Proxima Centauri might be more like our star than we thought.
For instance, our Sun has what is known as a “Solar Cycle“, an 11-year period in which it experiences changes in the levels of radiation it emits. This cycle is driven by changes in the Sun’s own magnetic field, and corresponds to the appearance of Sunspots on its surface. During a “solar minimum”, the Sun’s surface is clear of spots, while at a solar maximum, one hundred sunspots can appear on an area the size of 1% the Sun’s surface area.
For the sake of their research, the Harvard Smithsonian team examined Proxima Centauri over the course of several years to see if it too had a cycle. As they explain in their research paper, titled “Optical, UV, and X-Ray Evidence for a 7-Year Stellar Cycle in Proxima Centauri” they relied on several years worth optical, UV, and X-ray observations made of the star.
This included 15 years of visual data and 3 years of infrared data from the All Sky Automated Survey (ASAS), 4 years of x-ray and UV data from the Swift x-ray telescope (XRT), and 22 years worth of x-ray observations taken by the Advanced Satellite for Cosmology and Astrophysics (ASCA), the XXM-Newton mission and the Chandra X-ray Observatory.
What they found was that Proxima Centauri does indeed have a cycle that involves changes in its minimum and maximum amount of emitting radiation, which corresponds to “starspots” on its surface. As Dr. Wargelin told Universe Today via email:
“The optical/ASAS data showed a nice 7-year cycle, as well as an 83-day rotation period. When we broke down that data by year we saw the period vary from around 77 to 90 days. We interpret that as ‘differential rotation’ like that found on the Sun. The rotation rate differs at different latitudes; on the Sun it’s around 35 days at the poles and 24.5 at the equator. The “average” rotation is usually given as 27.3 days.”
In essence, Proxima Centauri has its own cycle, but one that is a lot more dramatic than our Sun’s. Besides lasting 7 years from peak to peak, it involves spots covering over 20% of its surface at one time. These spots are apparently much bigger than the ones we regularly observe on our Sun as well.
This was surprising, given that Proxima’s interior is very different from our Sun’s. Because of its low mass, the interior of Proxima Centauri is convective, where material in the core is transferred outward. In contrast, only the outer layer of our Sun undergoes convection while the core remains relatively still. This means that, unlike our Sun, energy is transferred to the surface through physical movement, and not radiative processes.
While these findings cannot tell us anything directly about whether or not Proxima b might be habitable, the existence of this solar cycle is an interesting find that might be leading in that general direction. As Dr. Wargelin explained:
“Magnetic fields are what drive high energy emission (UV and X rays) and stellar winds (like the solar wind) in solar-type and smaller stars, AND a stellar cycle (if it has one). That X-ray/UV emission and stellar wind can ionize/evaporate/strip the atmosphere of close-in planets, particularly if the planet doesn’t have a protective magnetic field of its own.
“Therefore….. a necessary but not sufficient requirement for understanding (i.e., modeling) the evolution of a planet’s atmosphere is understanding the magnetic field of the host star. If you don’t understand why a star has a cycle (and standard theory says fully convective stars like Proxima can NOT have cycles) then you don’t understand its magnetic field.”
As always, further observations and research will be necessary before we can fully understand Proxima Centauri, and whether or not any planets that orbit it could support life. But then again, we’ve only known about Proxima b for a short time, and the rate at which we are learning new things about it is quite impressive!
