The partial lunar eclipse on August 7, 2017 as seen from Bucharest, Romania. Credit and copyright: Loredana Jucan.
Just to get you in the mood for the upcoming total solar eclipse — now less than two weeks away — our Solar System put on a little eclipse display of the lunar kind on August 7. The full Moon passed through part of the Earth’s umbral shadow, and the timing made this partial lunar eclipse visible in parts of Europe and Africa.
Thanks to our friends around the world who posted in Universe Today’s Flickr page, we’ve got images to share! Enjoy the views! Click on all the images to see larger versions of them on Flickr. The lead image link is here.
And for those of you in the path of the August 21 solar eclipse, please feel free to share your images on our Flickr page, and we may feature them in an upcoming article.
A composite of images take during the August 2017 lunar eclipse, as see from Kuala Lumpur. Credit and copyright: Shahrin Ahmad.Partial lunar eclipse seen from Lausanne’s lakeshore in Switzerland … The Moon had just moved up from behind the Tour d’Aï Peaks. Credit and copyright: Hicham Dennaoui.Partial Eclipse of Moon over the Church of Our Lady of the Bell in Casarano, Sicily, Italy. Single photo taken with a Konus 80/400 telescope and Canon 700d camera. Credit and copyright: Gianluca Belgrado. Eclipsed full moon over the eastern horizon as seen from Treppendorf, Brandenburg, Germany. Credit and copyright: Andreas Schnabel.Partial lunar eclipse of August 7th 2017, as seen from Bavaria, Germany at around 19:17 UTC. Shot with an EOS 550D mounted to a Meade ETX 70 Telescope. Exposure was 1/125 seconds with ISO 100. Credit and copyright: Stephan Haverland. The partial lunar eclipse as see from Czolpino, Pomerania, Poland. Credit and copyright: Pawel Warchal. A view of the partial lunar eclipse on August 7, 2017 as seen from Malta in the Mediterranean Sea. Credit and copyright: Leonard Ellul-Mercer.
Here is a video of additional images from Leonard Mercer:
You can watch a reply of a live webcast from the Virtual Telescope Project of the partial lunar eclipse seen from Rome:
The Spallation Neutron Source, located at the Oak Ridge National Laboratory. Credit: neutrons.ornl.gov
Neutrinos are one of the fundamental particles that make up the Universe. Compared to other types of particles, they have very little mass, no charge, and only interact with others via the weak nuclear force and gravity. As such, finding evidence of their interactions is extremely difficult, requiring massive instruments located deep underground to shield them from any interference.
However, using the Spallation Neutron Source (SNS), a research facility located at the Oak Ridge National Laboratory (ORNL) – an international team of researchers recently made a historic discovery about neutrinos using an entirely different method. As part of the COHERENT experiment, these results confirm a prediction made 43 years ago and offers new possibilities for neutrino research.
Messier 53, as imaged by the Hubble Space Telescope. Credit: ESA/Hubble & NASA
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at globular cluster known as Messier 53!
During the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of these objects so others would not make the same mistake he did. In time, this list (known as the Messier Catalog) would come to include 100 of the most fabulous objects in the night sky.
One of these objects is Messier 53, a globular cluster located in the northern Coma Berenices constellation. Located about 58,000 light years from the Solar System, it is almost equidistant from Galactic Center (about 60,000 light years). As Messier Objects go, it is relatively easy to find since it lies in the same area of the sky as Arcturus, the fourth brightest star in the night sky.
Description:
Heading towards us at a speed of 112 kilometers per second, globular cluster M53 is one of the furthest distant globular clusters in our Milky Way halo and lay almost equally distant between our solar system and the galactic center. This 220 light year diameter ball of stars in tightly compacted towards its core – where low metal is the name of the game and RR Lyra type variable stars once ruled. But recent studies have found that there are some new kids on the block. The blue stragglers…
Messier 53, as imaged by the Hubble Space Telescope. Credit: ESA/Hubble & NASA
According to G. Beccari (et al) the population of these definitely appears to violate standard theories of stellar evolution. And there not just a few blues… There’s a whole host of them. As Beccari noted in a 2008 study:
“We used a proper combination of high-resolution and wide-field multiwavelength observations collected at three different telescopes (HST, LBT, and CFHT) to probe the blue straggler star (BSS) population in the globular cluster M53. Almost 200 BSSs have been identified over the entire cluster extension. We have also used this database to construct the radial star density profile of the cluster; this is the most extended and accurate radial profile ever published for this cluster, including detailed star counts in the very inner region. A deviation from the model is noted in the most external region of the cluster. This feature needs to be further investigated in order to address the possible presence of a tidal tail in this cluster.”
Is this possible? Then take a closer look into this research. One where a millisecond pulsar was discovered inside. As S.R. Kulkarni (et al) indicated in a 1991 study:
“Millisecond pulsars are conventionally assumed to be spun up through the action of binary companions, although some subsequently lose their companions and appear as isolated pulsars. Such objects should therefore be more numerous in dense stellar systems. We report here the surprising discovery of two pulsars in low-density globular clusters: one is a single 10-ms pulsar (1639+36) in M13 (NGC 6205), the other a 33-ms pulsar (1310+18) in a 256-d binary in M53 (NGC 5024). Their ages, inferred from their luminosities and constraints on their period derivatives, seem to be 10 9 years, significantly greater than previously reported ages ( ! 10 8 years) of cluster pulsars. The implied birth rate is inconsistent with the conventional two-body tidal capture model, suggesting that an alternative mechanism such as tidal capture between primordial binaries and a reservoir of (hundreds of) primordial neutron stars may dominate the production of tidal binaries in such clusters. The period derivative of PSR1639+36 is surprisingly small, and may be corrupted by acceleration due to the mean gravitational potential of the cluster.”
The Messier 53 globular star cluster. Credit: Ole Nielsen
History of Observation:
This globular cluster was first discovered on February 3, 1775 by Johann Elert Bode, but independently recovered on February 26, 1777 by Charles Messier who writes:
“Nebula without stars discovered below & near Coma Berenices, a little distant from the star 42 in that constellation, according to Flamsteed. This nebula is round and conspicuous. The Comet of 1779 was compared directly with this nebula, & M. Messier has reported it on the chart of that comet, which will be included in the volume of the Academy for 1779. Observed again April 13, 1781: It resembles the nebula which is below Lepus [M79].”
Sir William Herschel would revisit M53, but he did not publish his findings when studying Messier objects. Very seldom did Herschel wax poetic in his writings, but of this particular object he said: “A cluster of very close stars; one of the most beautiful objects I remember to have seen in the heavens. The cluster appears under the form of a solid ball, consisting of small stars, quite compressed into one blaze of light, with a great number of loose ones surrounding it, and distinctly visible in the general mass.”
He would return again in later years to include in his notes: “From what has been said it is obvious that here the exertion of a clustering power has brought the accumulation and artificial construction of these wonderful celestial objects to the highest degree of mysterious perfection.”
The Messier 53 globular cluster. Credit: NASA/ESA/Hubble
Although it did not touch Sir John Herschel quite so much, M53 also engaged Admiral Smyth who wrote:
“A globular cluster, between Berenice’s tresses and the Virgin’s left hand, with a coarse pair of telescopic stars in the sf [south following, SE] quadrant, and a single one in the sp [south preceding, SW]. This is a brilliant mass of minute stars, from the 11th to the 15th magnitude, and from thence to gleams of star-dust, with stragglers to the np [north preceding, NW], and pretty diffused edges. From the blaze at the centre, it is evidently a highly compressed ball of stars, whose law of aggregation into so dense and compact a mass, is utterly hidden from our imperfect senses. It was enrolled by Messier in 1774 as No. 53, and resolved into stars by Sir W. Herschel. The contemplation of so beautiful an object, cannot but set imagination to work, though the mind may be soon lost in astonishment at the stellar dispositions of the great Creator and Maintainer. Thus, in reasoning by analogy, these compressed globes of stars confound conjecture as to the models in which the mutual attractions are prevented from causing the universal destruction of their system. Sir John Herschel thinks, that no pressure can be propagated through a cluster of discrete stars; whence it would follow, that the permanence of its form must be maintained in a way totally different from that which our reasoning suggest. Before quitting this interesting ball of innumerable worlds, I may mention that it was examined by Sir John Herschel, with Mr. Baily, in the 20-foot reflector; and that powerful instrument showed the cluster with curved appendages of stars, like the short claws of a crab running out from the main body. A line through Delta and Epsilon Virginis, northward, meeting another drawn from Arcturus to Eta Bootis, unite upon this wonderful assemblage; or it is also easily found by its being about 1 deg northeast of 42 Comae Berenices, the alignment of which is already given.”
Locating Messier 53:
M53 can be easily found just about a degree northeast of 42 Alpha Comae Berenices, a visual binary star. To located Alpha, draw a mental line from Arcturus via Eta Bootis where you’ll see it about a fist width west. Alternately you can starhop from Gamma Viginis to Delta and on to Epsilon where you can locate M53 approximately 4 fingerwidths to the north/northeast.
To see this small globular cluster in binoculars will require dark skies and it will appear very small, like a large, out of focus star. In small telescopes it will appear almost cometary – and thus why Messier cataloged these objects! However, with telescopes approaching the 6″ range, resolution will begin and larger telescopes will shatter this gorgeous globular cluster. Requires dark skies.
The location of Messier 53 in the northern Coma Berenices constellation. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
A ball of worlds… What a unique description! May you enjoy your observations as well!
And here are the quick facts on this Messier Object to help you get started!
Object Name: Messier 53 Alternative Designations: M53, NGC 5024 Object Type: Class V Globular Cluster Constellation: Coma Berenices Right Ascension: 13 : 12.9 (h:m) Declination: +18 : 10 (deg:m) Distance: 58.0 (kly) Visual Brightness: 7.6 (mag) Apparent Dimension: 13.0 (arc min)
Welcome, come in to the 521st 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 #521”
SpaceX Falcon Heavy rocket poised for launch from the Kennedy Space Center in Florida in this artists concept. Credit: SpaceX
SpaceX Falcon Heavy rocket poised for launch from the Kennedy Space Center in Florida in this artists concept. Credit: SpaceX
Before the year is out, the long awaited debut launch of the triple barreled Falcon Heavy rocket may at last be in sight says SpaceX CEO and founder Elon Musk, as he forthrightly acknowledges it comes with high risk and released a stunning launch and landing animation earlier today, Aug. 4.
After years of painstaking development and delays, the inaugural blastoff of the SpaceX Falcon Heavy is currently slated for November 2017 from NASA’s Kennedy Space Center in Florida, according to Musk.
“Falcon Heavy maiden launch this November,” SpaceX CEO and billionaire founder Elon Musk tweeted last week.
“Lot that can go wrong in the November launch …,” Musk said today on Instagram, downplaying the chances of complete success.
And to whet the appetites of space enthusiasts worldwide, just today Musk also published a one minute long draft animation illustrating the Falcon Heavy triple booster launch and how the individual landings of the trio of first stage booster cores will take place – nearly simultaneously.
https://www.instagram.com/p/BXXiVWFgphb/
Video Caption: SpaceX Falcon Heavy launch from KSC pad 39A pad and first stage booster landings. Credit: SpaceX
“Side booster rockets return to Cape Canaveral,” explains Musk on twitter. “Center lands on droneship.”
The two side boosters will be recycled from prior Falcon 9 launches and make precision guided propulsive, upright ground soft landings back at Cape Canaveral Air Force Station, Florida. Each booster is outfitted with a quartet of grid fins and landing legs. The center core is newly built and heavily modified.
“Sides run high thrust, center is lower thrust until sides separate & fly back. Center then throttles up, keeps burning & lands on droneship. If we’re lucky!” Musk elaborated.
The center booster will touch down on an ocean going droneship prepositioned in the Atlantic Ocean some 400 miles (600 km) off of Florida’s east coast.
The launch of the extremely complicated Falcon Heavy booster with 27 first stage Merlin 1D engines also comes associated with a huge risk – and he hopes that it at least rises far enough off the ground to minimize the chances of damage to the historic pad 39A at the Kennedy Space Center.
“There’s a lot of risk associated with Falcon Heavy, a real good chance that that vehicle does not make it to orbit,” Musk said recently while speaking at the International Space Station Research and Development Conference in Washington, D.C. on July 19.
“I want to make sure to set expectations accordingly. I hope it makes it far enough beyond the pad so that it does not cause pad damage. I would consider even that a win, to be honest.”
Musk originally proposed the Falcon Heavy in 2011 and targeted a maiden mission in 2013.
Whenever it does launch, the Falcon Heavy will become the world’s most powerful rocket.
“I think Falcon Heavy is going to be a great vehicle,” Musk stated. “There’s just so much that’s really impossible to test on the ground, and we’ll do our best.
“Falcon Heavy requires the simultaneous ignition of 27 orbit-class engines. There’s a lot that can go wrong there.”
Designing and building Falcon Heavy has proven to be far more difficult than Musk ever imagined, and the center booster had to be significantly redesigned.
“It actually ended up being way harder to do Falcon Heavy than we thought,” Musk explained.
“At first it sounds real easy! You just stick two first stages on as strap-on boosters. How hard can that be?” But then everything changes. All the loads change, aerodynamics totally change. You’ve tripled the vibration and acoustics. You sort of break the qualification levels on so much of the hardware.”
“The amount of load you’re putting through that center core is crazy because you’ve got two super-powerful boosters also shoving that center core. So we had to redesign the whole center core airframe,” Musk added. “It’s not like the Falcon 9 – because it’s got to take so much load. Then you’ve got separation systems.”
Due to the high risk, there will be no payload from a paying customer housed inside the nose cone atop the center core. Only a dummy payload will be installed on the maiden mission.
However future Falcon Heavy missions have been manifested with commercial and science payloads.
Falcon Heavy will blast off with about twice the thrust of the Delta IV Heavy, currently the worlds most powerful rocket. The United Launch Alliance (ULA) Delta IV Heavy (D4H) has been the world’s mightiest rocket since the retirement of NASA’s Space Shuttles in 2011.
The Falcon Heavy sports about 2/3 the liftoff thrust of NASA’s Saturn V manned moon landing rockets – last launched in the 1970s.
SpaceX Falcon 9 blasts off with Intelsat 35e – 4th next gen ‘Epic’ TV and mobile broadband comsat for Intelsat – on July 5, 2017 at 7:38 p.m. EDT from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
The Falcon Heavy is comprised of three Falcon 9 cores. The Delta IV Heavy is comprised of three Delta Common Core Boosters.
The combined trio of Falcon 9 cores will generate about 5.1 million pounds of liftoff thrust upon ignition from Launch Complex 39A at the Kennedy Space Center in Florida.
“With the ability to lift into orbit over 54 metric tons (119,000 lb)–a mass equivalent to a 737 jetliner loaded with passengers, crew, luggage and fuel–Falcon Heavy can lift more than twice the payload of the next closest operational vehicle, the Delta IV Heavy, at one-third the cost,” according to the SpaceX website.
“The nice thing is when you fully optimize it, it’s about two-and-a-half times the payload capability of a Falcon 9,” Musk notes. “It’s well over 100,000 pounds to LEO of payload capability, 50 tons. It can even get up a little higher than that if optimized.”
ULA Delta 4 Heavy rocket delivers NROL-37 spy satellite to orbit on June 11, 2016 from Space Launch Complex-37 on Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com
The two stage Falcon Heavy stands more than 229.6 feet (70 meters) tall and is 39.9 feet wide (12.2 meters).
It weighs more than 3.1 million pounds (1.4 million kilograms).
Like the Falcon 9 it will be fueled with liquid oxygen and RP-1 kerosene propellants.
The thunder, power and roar of over 5 million pounds of liftoff thrust from the Falcon Heavy’s 27 engines is absolutely certain to be a thrilling, earth-shaking space spectacular !! Thus placing it in a class of its own unlike any US launch since NASA’s Saturn V and Space Shuttles rocketed to the high frontier from the same pad.
“I encourage people to come down to the Cape to see the first Falcon Heavy mission,” Musk said. “It’s guaranteed to be exciting.”
But before the Falcon Heavy can actually be rolled up to launch position at pad 39A, SpaceX must first complete repairs and refurbishment to nearby pad 40.
That Cape pad was heavily damaged nearly a year ago during a catastrophic launch pad explosion that took place in Sept. 2016 during a routine prelaunch fueling and static fire engine test of a Falcon 9 rocket with the Amos-6 commercial comsat payload bolted on top.
Pad 40 must achieve operational launch status again before SpaceX can commit to the Falcon Heavy launches at Pad 39A. Workers will also need to finish construction work at pad 39A to support the Heavy launches.
SpaceX Falcon 9 booster deploys quartet of landing legs moments before precision propulsive ground touchdown at Landing Zone 1 on Canaveral Air Force Station barely nine minutes after liftoff from Launch Complex 39A on 3 June 2017 from the Kennedy Space Center in Florida on the Dragon CRS-11 resupply mission to the International Space Station for NASA. Credit: Ken Kremer/Kenkremer.com
To date SpaceX has successfully demonstrated the recovery of thirteen boosters by land and sea.
Furthermore SpaceX engineers have advanced to the next step and successfully recycled, reflown and relaunched two ‘flight-proven first stages this year in March and June of 2017 from the Kennedy Space Center in Florida involving the SES-10 and BulgariaSat-1 launches respectively.
SpaceX CEO and Chief Designer Elon Musk and SES CTO Martin Halliwell exuberantly shake hands of congratulation following the successful delivery of SES-10 TV comsat to orbit using the first reflown and flight proven booster in world history at the March 30, 2017 post launch media briefing at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/Kenkremer.com
The next SpaceX Falcon 9 launch is slated for Aug. 13 on the NASA contracted CRS-12 resupply mission to the ISS.
Watch for Ken’s onsite space mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
SpaceX Falcon 9 Booster leaning atop OCISLY droneship upon which it landed after 23 June launch from KSC floats into Port Canaveral, FL, on 29 June 2017, hauled by tugboat as seen from Jetty Park Pier. Credit: Ken Kremer/kenkremer.com
Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida- as seen from the crawlerway. Credit: Ken Kremer/kenkremer.com
Earth's Greatest Hits: the Golden Record attached to the Voyager 1 and 2 spacecraft. Credit: NASA/JPL.
Forty years ago, the Voyager 1 and 2 missions began their journey from Earth to become the farthest-reaching missions in history. In the course of their missions, the two probes spent the next two decades sailing past the gas giants of Jupiter and Saturn. And while Voyager 1 then ventured into the outer Solar System, Voyager 2 swung by Uranus and Neptune, becoming the first and only probe in history to explore these worlds.
This summer, the probes will be marking the fortieth anniversary of their launch – on September 5th and August 20th, respectively. Despite having traveled for so long and reaching such considerable distances from Earth, the probes are still in contact with NASA and sending back valuable data. So in addition to being the most distant missions from Earth, they are the longest-running mission in history.
In addition to their distance and longevity, the Voyager spacecraft have also set numerous other records for robotic space missions. For example, in 2012, the Voyager 1 probe became the first and only spacecraft to have entered interstellar space. Voyage 2, meanwhile, is the only probe that has explored all four of the Solar System’s gas/ice giants – Jupiter, Saturn, Uranus and Neptune.
The launch of the Voyager 2 probe, which took place on August 20th, 1977. Credit: NASA
Their discoveries also include the first active volcanoes beyond Earth – on Jupiter’s moon Io – the first evidence of a possible subsurface ocean on Europa, the dense atmosphere around Titan (the only body beyond Earth with a dense, nitrogen-rich atmosphere), the craggy surface of Uranus’ “Frankenstein Moon” Miranda, and the ice plume geysers of Neptune’s largest moon, Triton.
These accomplishments have had immeasurable benefits for planetary science, astronomy and space exploration. They’ve also paved the way for future missions, such as the Galileo and Juno probes, the Cassini-Huygens mission, and the New Horizons spacecraft. As Thomas Zurbuchen, the associate administrator for NASA’s Science Mission Directorate (SMD), said in a recent press statement:
“I believe that few missions can ever match the achievements of the Voyager spacecraft during their four decades of exploration. They have educated us to the unknown wonders of the universe and truly inspired humanity to continue to explore our solar system and beyond.”
But what is perhaps most memorable about the Voyager missions is the special cargo they carry. Each spacecraft carries what is known as the Golden Record, a collection of sounds, pictures and messages that tell of Earth, human history and culture. These records were intended to serve as a sort of time capsule and/or message to any civilizations that retrieved them, should they ever be recovered.
Each of the two Voyager spacecraft launched in 1977 carry a 12-inch gold-plated phonograph record with images and sounds from Earth. Credit: NASA
As noted, both ships are still in contact with NASA and sending back mission data. The Voyager 1 probe, as of the writing of this article, is about 20.9 billion km (13 billion mi; 140 AU) from Earth. As it travels northward out of the plane of the planets and into interstellar space, the probe continues to send back information about cosmic rays – which are about four times as abundant in interstellar space than around Earth.
From this, researchers have learned that the heliosphere – the region that contains the Solar System’s planets and solar wind – acts as a sort of radiation shield. Much in the say that Earth’s magnetic field protects us from solar wind (which would otherwise strip away our atmosphere), the heliopause protects the Solar planets from atomic nuclei that travel at close to the speed of light.
Voyager 2, meanwhile, is currently about 17.7 billion km (11 billion mi; 114.3 AU) from Earth. It is traveling south out of the plane of the planets, and is expected to enter interstellar space in a few years. And much like Voyager 1, it is also studying how the heliosphere interacts with the surroundings interstellar medium, using a suite of instruments that measure charged particles, magnetic fields, radio waves and solar wind plasma.
Once Voyager 2 crosses into interstellar space, both probes will be able to sample the medium from two different locations simultaneously. This is expected to tell us much about the magnetic environment that encapsulates our system, and will perhaps teach us more about the history and formation of the Solar System. On top of that, it will let us know what kinds of hazards a possible interstellar mission will have to contend with.
Illustration showing how NASA’s Hubble Space Telescope is looking along the paths of NASA’s Voyager 1 and 2 spacecraft as they journey through the solar system and into interstellar space. Credit: NASA/ESA/Z. Levy (STScI)
The fact that the two probes are still active after all this time is nothing short of amazing. As Edward Stone – the David Morrisroe Professor of Physics at Caltech, the former VP and Director of NASA’s Jet Propulsion Laboratory, and the Voyager project scientist – said:
“None of us knew, when we launched 40 years ago, that anything would still be working, and continuing on this pioneering journey. The most exciting thing they find in the next five years is likely to be something that we didn’t know was out there to be discovered.”
Keeping the probes going has also been a challenge since the amount of power they generate decreases at a rate of about four watts per year. This has required that engineers learn how to operate the twin spacecraft with ever-decreasing amounts of power, which has forced them to consult documents that are decades old in order to understand the probes’ software and command functions.
Luckily, it has also given former NASA engineers who worked on the Voyager probes the opportunity to offer their experience and expertise. At present, the team that is operating the spacecraft estimate that the probes will run out of power by 2030. However, they will continue to drift along their trajectories long after they do so, traveling at a speed of 48,280 km per hour (30,000 mph) and covering a single AU every 126 days.
The Voyager 1 spacecraft has started to transverse what JPL has dubbed as a “cosmic purgatory” between our solar system – and interstellar space. Credit: NASA/JPL
At this rate, they will be within spitting distance of the nearest star in about 40,000 years, and will have completed an orbit of the Milky Way within 225 million years. So its entirely possible that someday, the Golden Records will find their way to a species capable of understanding what they represent. Then again, they might find their way back to Earth someday, informing our distant, distant relatives about life in the 20th century.
And if the craft avoid any catastrophic collisions and can survive in the interstellar medium of space, it is likely that they will continue to be emissaries for humanity long after humanity is dead. It’s good to leave something behind!
Artist’s impression of Proxima b, which was discovered using the Radial Velocity method. Credit: ESO/M. Kornmesser
Back in of August of 2016, the existence of an Earth-like planet right next door to our Solar System was confirmed. To make matters even more exciting, it was confirmed that this planet orbits within its star’s habitable zone too. Since that time, astronomers and exoplanet-hunters have been busy trying to determine all they can about this rocky planet, known as Proxima b. Foremost on everyone’s mind has been just how likely it is to be habitable.
However, numerous studies have emerged since that time that indicate that Proxima b, given the fact that it orbits an M-type (red dwarf), would have a hard time supporting life. This was certainly the conclusion reached in a new study led by researchers from NASA’s Goddard Space Flight Center. As they showed, a planet like Proxima b would not be able to retain an Earth-like atmosphere for very long.
Red dwarf stars are the most common in the Universe, accounting for an estimated 70% of stars in our galaxy alone. As such, astronomers are naturally interested in knowing just how likely they are at supporting habitable planets. And given the distance between our Solar System and Proxima Centauri – 4.246 light years – Proxima b is considered ideal for studying the habitability of red dwarf star systems.
This infographic compares the orbit of the planet around Proxima Centauri (Proxima b) with the same region of the Solar System. Credit: Pale Red Dot
On top of all that, the fact that Proxima b is believed to be similar in size and composition to Earth makes it an especially appealing target for research. The study was led by Dr. Katherine Garcia-Sage of NASA’s Goddard Space Flight Center and the Catholic University of America in Washington, DC. As she told Universe Today via email:
“So far, not many Earth-sized exoplanets have been found orbiting in the temperate zone of their star. That doesn’t mean they don’t exist – larger planets are found more often because they are easier to detect – but Proxima b is of interest because it’s not only Earth-sized and at the right distance from its star, but it’s also orbiting the closest star to our Solar System.”
For the sake of determining if Proxima b could be habitable, the research team sought to address the chief concerns facing rocky planets that orbit red dwarf stars. These include the planet’s distance from its stars, the variability of red dwarfs, and the presence (or absence) of magnetic fields. Distance is of particular importance since habitable zones (aka. temperate zones) around red dwarfs are much closer and tighter.
“Red dwarfs are cooler than our own Sun, so the temperate zone is closer to the star than Earth is to the Sun,” said Dr. Garcia-Sage. “But these stars may be very magnetically active, and being so close to a magnetically active star means that these planets are in a very different space environment than what the Earth experiences. At those distances from the star, the ultraviolet and x-ray radiation may be quite large. The stellar wind may be stronger. There could be stellar flares and energetic particles from the star that ionize and heat the upper atmosphere.”
At one time, Mars had a magnetic field similar to Earth, which prevented its atmosphere from being stripped away. Credit: NASA
In addition, red dwarf stars are known for being unstable and variable in nature when compared to our Sun. As such, planets orbiting in close proximity would have to contend with flare ups and intense solar wind, which could gradually strip away their atmospheres. This raises another important aspect of exoplanet habitability research, which is the presence of magnetic fields.
To put it simply, Earth’s atmosphere is protected by a magnetic field that is driven by a dynamo effect in its outer core. This “magnetosphere” has prevented solar wind from stripping our atmosphere away, thus giving life a chance to emerge and evolve. In contrast, Mars lost its magnetosphere roughly 4.2 billion years ago, which led to its atmosphere being depleted and its surface becoming the cold, desiccated place it is today.
To test Proxima b’s potential habitability and capacity to retain liquid surface water, the team therefore assumed the presence of an Earth-like atmosphere and a magnetic field around the planet. They then accounted for the enhanced radiation coming from Proxima b. This was provided by the Harvard Smithsonian Center for Astrophysics (CfA), where researchers determined the ultraviolet and x-ray spectrum of Proxima Centauri for this project.
From all of this, they constructed models that began to calculate the rate of atmospheric loss, using Earth’s atmosphere as a template. As Dr. Garcia-Sage explained:
“At Earth, the upper atmosphere is ionized and heated by ultraviolet and x-ray radiation from the Sun. Some of these ions and electrons escape from the upper atmosphere at the north and south poles. We have a model that calculates how fast the upper atmosphere is lost through these processes (it’s not very fast at Earth)… We then used that radiation as the input for our model and calculated a range of possible escape rates for Proxima Centauri b, based on varying levels of magnetic activity.”
Artist’s impression of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. The double star Alpha Centauri AB is visible to the upper right of Proxima itself. Credit: ESO
What they found was not very encouraging. In essence, Proxima b would not be able to retain an Earth-like atmosphere when subjected to Proxima Centauri’s intense radiation, even with the presence of a magnetic field. This means that unless Proxima b has had a very different kind of atmospheric history than Earth, it is most likely a lifeless ball of rock.
However, as Dr. Garcia-Sage put it, there are other factors to consider which their study simply can’t account for:
“We found that atmospheric losses are much stronger than they are at Earth, and the for high levels of magnetic activity that we expect at Proxima b, the escape rate was fast enough that an entire Earth-like atmosphere could be lost to space. That doesn’t take into account other things like volcanic activity or impacts with comets that might be able to replenish the atmosphere, but it does mean that when we’re trying to understand what processes shaped the atmosphere of Proxima b, we have to take into account the magnetic activity of the star. And understanding the atmosphere is an important part of understanding whether liquid water could exist on the surface of the planet and whether life could have evolved.”
So it’s not all bad news, but it doesn’t inspire a lot of confidence either. Unless Proxima b is a volcanically-active planet and subject to a lot of cometary impacts, it is not likely be temperate, water-bearing world. Most likely, its climate will be analogous to Mars – cold, dry, and with water existing mostly in the form of ice. And as for indigenous life emerging there, that’s not too likely either.
These and other recent studies have painted a rather bleak picture about the habitability of red dwarf star systems. Given that these are the most common types of stars in the known Universe, the statistical likelihood of finding a habitable planet beyond our Solar System appears to be dropping. Not exactly good news at all for those hoping that life will be found out there within their lifetimes!
But it is important to remember that what we can say definitely at this point about extra-solar planets is limited. In the coming years and decades, next-generation missions – like the James Webb Space Telescope (JWST) and the Transiting Exoplanet Survey Satellite (TESS) – are sure to paint a more detailed picture. In the meantime, there’s still plenty of stars in the Universe, even if most of them are extremely far away!
Artist's concept of the hot Jupiter WASP-121b, which presents the best evidence yet of a stratosphere on an exoplanet - generated using Engine House VFX. Credit: Bristol Science Centre/University of Exeter
Extra-solar planet discoveries have been exploding in recent years. In fact, as of Aug. 1st, 2017, astronomers have identified 3,639 exoplanets in 2,729 planetary systems and 612 multiple planetary systems. And while the majority of these have been discovered by Kepler – which has detected a total of 5,017 candidates and confirmed the existence of 2,494 exoplanets since 2009 – other instruments have played an important role in these discoveries as well.
This includes the Hubble Space Telescope, which in recent years has been dedicated to the detection of atmospheres around distant planets. Most recently, it was used in a survey that produced the strongest evidence to date for the existence of a stratosphere – a layer of atmosphere in which temperature increases with altitude – around a gas giant located about 900 light-years from our Solar System.
The study, titled “An ultrahot gas-giant exoplanet with a stratosphere“, recently appeared in the journal Nature. Led by Thomas Evans, a Research Fellow from the Astrophysics Group at the University of Exeter, the team relied on data provided by NASA’s Hubble Space Telescope to study a planet known as WASP-121b, a gas giant that orbits a yellow-white star that is slightly larger than our own.
The top of the planet’s atmosphere is heated to a blazing 2,500 °C (4,600 °F), hot enough to boil some metals. Credit: NASA/ESA/G. Bacon (STSci)
The planet itself has roughly 1.2 times the mass of Jupiter, has a radius that is about 1.9 times that of Jupiter, and has an orbital period of just 1.3 days. This is due to its close proximity to its sun, which makes it a particularly “Hot Jupiter”. In fact, if this exoplanet were any closer to its star, it is estimated that WASP-121’s gravity would begin to tear it apart.
It is also this close proximity that super-heats the planet’s atmosphere, driving temperatures up to 2,500 °C (4,600 °F). As Mark Marley, a researcher with NASA’s Ames Research Center and a co-author on the study, indicated in a NASA press statement:
“This result is exciting because it shows that a common trait of most of the atmospheres in our solar system — a warm stratosphere — also can be found in exoplanet atmospheres. We can now compare processes in exoplanet atmospheres with the same processes that happen under different sets of conditions in our own solar system.”
Whereas Hubble has found possible signs of stratospheres around WASP-33b and other hot Jupiters in the past, this new study presents the strongest evidence to date for the existence of an exoplanet stratosphere. The reason for this has to do with the spectrographic data obtained by Hubble of WASP-121b’s atmosphere, which indicated the presence of water vapor – which is a first as far as hot-Jupiter’s are concerned.
As Tom Evans – also a Research Fellow at the University of Exeter and the lead author on the paper – explained, these findings confirmed something that astronomers have suspected for some time. “Theoretical models have suggested stratospheres may define a distinct class of ultra-hot planets, with important implications for their atmospheric physics and chemistry,” he said. “Our observations support this picture.”
To study WASP-121b’s stratosphere, the team relied on spectroscopic data gathered by Hubble’s Wide Field Camera 3. After analyzing the different wavelengths that were part of WASP-121b’s light cure, they noted that certain wavelengths were glowing rather brightly in the infrared band. This, they concluded, was due to the presence of water vapor at the top of the planet’s atmosphere.
“The emission of light from water means the temperature is increasing with height,” Tiffany Kataria, one of the co-authors on the study from NASA’s Jet Propulsion Laboratory, said. “We’re excited to explore at what longitudes this behavior persists with upcoming Hubble observations.”
Beyond being the most convincing case so far of an exoplanet having a stratosphere, WASP-121b is also interesting because of just how hot this hot Jupiter is. Based on their data, the team concluded that temperatures in the atmosphere increased with altitude – a defining characteristic of a stratosphere. In Earth’s stratosphere, this process is driven by ozone, which traps the Sun’s ultraviolet light and raises the temperature of the surrounding molecules.
Artist’s concept of “hot Jupiter” exoplanet, a gas giant that orbits very close to its star. Credit: NASA/JPL-Caltech)
However, the temperature of Earth’s stratosphere does not exceed 270 K (-3°C; 26.6°F). When one considers other Solar Planets that also have stratosphere’s – like Saturn’s moon Titan, which experiences heating due to the interaction of solar radiation, energetic particles and methane – temperatures don’t change by more than 56 °C (100 °F). But in the case of WASP-121b, temperatures in the stratosphere increase by about 560 °C (1,000 °F).
Not even Venus, the hottest planet in the Solar System, can compete with that! On Earth’s “Sister Planet”, temperatures remain steady at about 735 K (462 °C; 863 °F), which is hot enough to melt lead. But on WASP-121b, temperatures reach over four times as high! This means the planet’s atmosphere is hot enough to melt stainless steel and other metals – like beryllium, platinum and zirconium.
At present, scientists do not now what chemicals are driving this temperature increase. Some possibilities have been suggested though, such as vanadium oxide and titanium oxide. Not only are these compounds believed to be common to brown dwarfs (aka. “failed stars”, which have much in common with gas giants), they also require the hottest temperatures possible in order to keep them in a gaseous state.
In any case, this distant gas giant has proven to be an interesting case study. In the future, research into this and other “super-hot Jupiters” is likely to challenge and expand our current understanding of how atmospheric forms and behave over time.
In the future, planetary protection (where we ensure that missions do not contaminate other words with Earth-borne organisms) will be especially important. Credit: NASA, JPL-Caltech
NASA has always had its fingers in many different pies. This should come as no surprise, since the advancement of science and the exploration of the Universe requires a multi-faceted approach. So in addition to studying Earth and distant planets, the also study infectious diseases and medical treatments, and ensuring that food, water and vehicles are safe. But protecting Earth and other planets from contamination, that’s a rather special job!
For decades, this responsibility has fallen to the NASA Office of Planetary Protection, the head of which is known as the Planetary Protection Officer (PPO). Last month, NASA announced that it was looking for a new PPO, the person whose job it will be to ensure that future missions to other planets don’t contaminate them with microbes that have come along for the ride, and that return missions don’t bring extra-terrestrial microbes back to Earth.
Since the beginning of the Space Age, federal agencies have understood that any and all missions carried with them the risk of contamination. Aside from the possibility that robotic or crewed missions might transport Earth microbes to foreign planets (and thus disrupt any natural life cycles there), it was also understood that missions returning from other bodies could bring potentially harmful organisms back to Earth.
Back when NASA was still in the midst of the Apollo Program, it was decided that steps needed to be taken to ensure that missions to other bodies did not cause contaminated. Credit: NASA
As such, the Office of Planetary Protection was established in 1967 to ensure that these risks were mitigated using proper safety and sterilization protocols. This was shortly after the United Nation’s Office of Outer Space Affairs (UNOOSA) drafted the Outer Space Treaty, which was signed by the United States, the United Kingdom, and the Soviet Union (as of 2017, 107 countries have become party to the treaty).
The goals of the Office of Planetary Protection are consistent with Article IX of the Outer Space Treaty; specifically, the part which states:
“States Parties to the Treaty shall pursue studies of outer space, including the Moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose.”
For decades, these directives have been followed to ensure that missions to the Moon, Mars and the Outer Solar System did not threaten these extra-terrestrial environments. For example, after eight years studying Jupiter and its largest moons, the Galileo probe was deliberately crashed into Jupiter’s atmosphere to ensure that none of its moons (which could harbor life beneath their icy surfaces) were contaminated by Earth-based microbes.
Artist’s concept of the Galileo space probe passing through the Jupiter system. Credit: NASA
The same procedure will be followed by the Juno mission, which is currently in orbit around Jupiter. Barring a possible mission extension, the probe is scheduled to be deorbited after conducting a total of 12 orbits of the gas giant. This will take place in July of 2018, at which point, the craft will burn up to avoid contaminating the Jovian moons of Europa, Ganymede and Callisto.
The same holds true for the Cassinispacecraft, which is currently passing between Saturn and its system of rings, as part of the mission’s Grand Finale. When this phase of its mission is complete – on September 15th, 2017 – the probe will be deorbited into Saturn’s atmosphere to prevent any microbes from reaching Enceladus, Titan, Dione, moons that may also support life in their interiors (or in Titan’s case, even on its surface!)
To be fair, the position of a Planetary Protection Officer is not unique to NASA. The European Space Agency (ESA), the Japanese Aerospace and Exploration Agency (JAXA) and other space agencies have similar positions. However, it is only within NASA and the ESA that it is considered to be a full-time job. The position is held for three years (with a possible extension to five) and is compensated to the tune of $124,406 to $187,000 per year.
The job, which can be applied for on USAJOBS.gov (and not through the Office of Planetary Protection), will remain open until August 18th, 2017. According to the posting, the PPO will be responsible for:
Leading planning and coordinating activities related to NASA mission planetary protection needs.
Leading independent evaluation of, and providing advice regarding, compliance by robotic and human spaceflight missions with NASA planetary protection policies, statutory requirements and international obligations.
Advising the Chief, SMA and other officials regarding the merit and implications of programmatic decisions involving risks to planetary protection objectives.
In coordination with relevant offices, leading interactions with COSPAR, National Academies, and advisory committees on planetary protection matters.
Recommending and leading the preparation of new or revised NASA standards and directives in accordance with established processes and guidelines.
What’s more, the fact that NASA is advertising the position is partly due to some recent changes to the role. As Catharine Conley*, NASA’s only planetary protection officer since 2014, indicated in a recent interview with Business Insider: “This new job ad is a result of relocating the position I currently hold to the Office of Safety and Mission Assurance, which is an independent technical authority within NASA.”
While the position has been undeniably important in the past, it is expected to become of even greater importance given NASA’s planned activities for the future. This includes NASA’s proposed “Journey to Mars“, a crewed mission which will see humans setting foot on the Red Planet sometime in the 2030s. And in just a few years time, the Mars 2020 rover is scheduled to begin searching the Martian surface for signs of life.
As part of this mission, the Mars 2020 rover will collect soil samples and place them in a cache to be retrieved by astronauts during the later crewed mission. Beyond Mars, NASA also hopes to conduct mission to Europa, Enceladus and Titan to look for signs of life. Each of these worlds have the necessary ingredients, which includes the prebiotic chemistry and geothermal energy necessary to support basic lifeforms.
Given that we intend to expand our horizons and explore increasingly exotic environments in the future – which could finally lead to the discovery of life beyond Earth – it only makes sense that the role of the Planetary Protection Officer become more prominent. If you think you’ve got the chops for it, and don’t mind a six-figure salary, be sure to apply soon!
*According to BI, Conley has not indicated if she will apply for the position again.
Artist's impression of the view from a hypothetical moon around a exoplanet orbiting a triple star system. Credit: NASA
Ever since it was deployed in March of 2009, the Kepler mission has detected thousands of extra-solar planet candidates. In fact, between 2009 and 2012, it detected a total of 4,496 candidates, and confirmed the existence of 2,337 exoplanets. Even after two of its reaction wheels failed, the spacecraft still managed to turn up distant planets as part of its K2 mission, accounting for another 521 candidates and confirming 157.
However, according to a new study conducted by a pair of researches from Columbia University and a citizen scientist, Kepler may also have also found evidence of an extra-solar moon. After sifting through data from hundreds of transits detected by the Kepler mission, the researchers found one instance where a transiting planet showed signs of having a satellite.
Their study – which recently published online under the title “HEK VI: On the Dearth of Galilean Analogs in Kepler and the Exomoon Candidate Kepler-1625b I” – was by led Alex Teachey, a graduate student at Columbia University and a Graduate Research Fellow with the National Science Foundation (NSF). He was joined by David Kipping, an Assistant Professor of Astronomy at Columbia University and the Principal Investigator of The Hunt for Exomoons with Kepler (HEK) project, and Allan Schmitt, a citizen scientist.
Artist’s impression of NASA’s Kepler spacecraft. Credit: NASA
For years, Dr. Kipping has been searching the Kepler database for evidence of exomoons, as part of the HEK. This is not surprising, considering the kinds of opportunities that exomoons present for scientific research. Within our Solar System, the study of natural satellites has revealed important things about the mechanisms that drive early and late planet formation, and moons possess interesting geological features that are commonly found on other bodies.
It is for this reason that extending that research to the hunt for exoplanets is seen as necessary. Already, exoplanet-hunting missions like Kepler have turned up a wealth of planets that challenge conventional ideas about how planet formation and what kinds of planets are possible. The most noteworthy example are gas giants that have observed orbiting very close to their stars (aka. “Hot Jupiters”).
As such, the study of exomoons could yield valuable information about what kinds of satellites are possible, and whether or not our own moons are typical. As Teachey told Universe Today via email:
“Exomoons could tell us a lot about the formation of our Solar System, and other star systems. We see moons in our Solar System, but are they common elsewhere? We tend to think so, but we can’t know for sure until we actually see them. But it’s an important question because, if we find out there aren’t very many moons out there, it suggests maybe something unusual was going on in our Solar System in the early days, and that could have major implications for how life arose on the Earth. In other words, is the history of our Solar System common across the galaxy, or do we have a very unusual origin story? And what does that say about the chances of life arising here? Exomoons stand to offer us clues to answering these questions.”
A montage of some of the potentially-habitable moons in our Solar System. From top to bottom, left to right, these include Europa, Enceladus, TItan and Ceres. Credit: NASA/JPL
What’s more, many moons in the Solar System – including Europa, Ganymede, Enceladus and Titan – are thought to be potentially habitable. This is due to the fact that these bodies have steady supplies of volatiles (such as nitrogen, water, carbon dioxide, ammonia, hydrogen, methane and sulfur dioxide) and possess internal heating mechanisms that could provide the necessary energy to power biological processes.
Here too, the study of exomoons presents interesting possibilities, such as whether or not they may be habitable or even Earth-like. For these and other reasons, astronomers want to see if the planets that have been confirmed in distant star systems have systems of moons and what conditions are like on them. But as Teachey indicated, the search for exomoons presents a number of challenges compared to exoplanet-hunting:
“Moons are difficult to find because 1) we expect them to be quite small most of the time, meaning the transit signal will be quite weak to begin with, and 2) every time a planet transits, the moon will show up in a different place. This makes them more difficult to detect in the data, and modeling the transit events is significantly more computationally expensive. But our work leverages the moons showing up in different places by taking the time-averaged signal across many different transit events, and even across many different exoplanetary systems. If the moons are there, they will in effect carve out a signal on either side of the planetary transit over time. Then it’s a matter of modeling this signal and understanding what it means in terms of moon size and occurrence rate.”
To locate signs of exomoons, Teachey and his colleagues searched through the Kepler database and analyzed the transits of 284 exoplanet candidates in front of their respective stars. These planets ranged in size from being Earth-like to Jupiter-like in diameter, and orbited their stars at a distance of between ~0.1 to 1.0 AU. They then modeled the light curve of the stars using the techniques of phase-folding and stacking.
An artist’s conception of a habitable exomoon. Credit: NASA
These techniques are commonly used by astronomers who monitor stars for dips in luminosity that are caused by the transits of planets (i.e. the transit method). As Teachey explained, the process is quite similar:
“Basically we cut up the time-series data into equal pieces, each piece having one transit of the planet in the middle. And when we stack these pieces together we’re able to get a clearer picture of what the transit looks like… For the moon search we do essentially the same thing, only now we’re looking at the data outside the main planetary transit. Once we stack the data, we take the average values of all the data points within a certain time window and, if a moon is present, we ought to see some missing starlight there, which allows us to deduce its presence.”
What they found was a single candidate located in the Kepler-1625 system, a yellow star located about 4000 light years from Earth. Designated Kepler-1625B I, this moon orbits the large gas giant that is located within the star’s habitable zone, is 5.9 to 11.67 times the size of Earth, and orbits its star with a period of 287.4 days. This exomoon candidate, if it should be confirmed, will be the first exomoon ever discovered
The team’s results (which await peer review) also demonstrated that large moons to be a rare occurrence in the inner regions of star systems (within 1 AU). This was something of a surprise, though Teachey acknowledges that it is consistent with recent theoretical work. According to what some recent studies suggest, large planets like Jupiter could lose their moons as they migrate inward.
If this should prove to be the case, then what Teachey and his colleagues witnessed could be seen as evidence of that process. It could also be an indication our current exoplanet-hunting missions may not be up to the task of detecting exomoons. In the coming years, next-generations missions are expected to provide more detailed analyses of distant stars and their planetary systems.
An artist’s conception of a distance exomoon blocking out a star’s light. Credit: Dan
However, as Teachey indicated, these too could be limited in terms of what they can detect, and new strategies may ultimately be needed:
“The rarity of moons in the inner regions of these star systems suggests that individual moons will remain difficult to find in the Kepler data, and upcoming missions like TESS, which should find lots of very short period planets, will also have a difficult time finding these moons. It’s likely the moons, which we still expect to be out there somewhere, reside in the outer regions of these star systems, much as they do in our Solar System. But these regions are much more difficult to probe, so we will have to get even more clever about how we look for these worlds with present and near-future datasets.”
In the meantime, we can certainly be exited about the fact that the first exomoon appears to have been discovered. While these results await peer review, confirmation of this moon will mean additional research opportunities for Kepler-1625 system. The fact that this moon orbits within the star’s habitable zone is also an interesting feature, though its not likely the moon itself is habitable.
Still, the possibility of a habitable moon orbiting a gas giant is certainly interesting. Does that sound like something that might have come up in some science fiction movies?
