This week, we are SUPER excited to welcome author Andy Weir (The Martian), back to the show to chat with us about his new book, Artemis. Viewers who have seen Andy’s first appearance on our show on January 9, 2015, will remember just how awesome he is as a guest – and why we can’t wait to catch up with him this week.
Andy began his career as a software engineer but wrote science fiction stories in his spare time. His novel, THE MARTIAN, was a blockbuster success which has allowed him to pursue his writing full-time. He is a lifelong space nerd and a devoted hobbyist of subjects such as relativistic physics, orbital mechanics, and the history of manned spaceflight.
The WSH Crew is doing another book giveaway – this time in conjunction with Dean Regas‘ joining us again on November 29th in a pre-recorded interview. Dean’s new book, “100 Things to See in the Night Sky” hits the stores on November 28th, but we are giving our viewers a chance to win one of two copies of Dean’s book! (Note: telescope not included!)
To enter for a chance to win, send an email to [email protected] with the Subject ‘100 Things’. Be sure to include your name and email address in the body of your message so that we can contact our winners afterward.
To be eligible, your entry must be postmarked no later than 11:59:59 PM EST on Monday, November 27, 2017. Two winners will be selected at random from all eligible entries live on the show, by Fraser, on Wednesday, November 29th. No purchase is necessary. You do not need to be watching the show live to win. Contest is open to all viewers worldwide. Limit: One entry per person – duplicate entries will be ignored.
The man in the moon, the pyramids on Mars. Every cloud, ever. Humans have a tendency to pattern match when they’re looking around the Universe – it’s called pareidolia. What causes this behavior, and how can we use this to debunk some hilarious conspiracy theories?
John B. Charles, Ph.D., is the Chief Scientist of NASA’s Human Research Program (HRP), responsible for the scientific direction of human research and technology development enabling astronauts to go beyond low Earth orbit and eventually to Mars.
If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!
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Following the Moon and wondering where are the fleeting inner solar system planets are this month?
While Jupiter and Saturn sink into the dusk on the far side of the Sun this month, the real action transpires in the dawn sky in mid-September, with a complex set of early morning conjunctions, groupings and occultations.
First, let’s set the stage for the planetary drama. Mercury just passed greatest elongation 18 degrees west of the Sun on September 12th.
The action warms up with a great pre-show on the morning of Saturday, September 16th, when the closest conjunction of two naked eye planets for 2017 occurs, as Mercury passes just 3′ north of Mars. The conjunction occurs at 16:00 UT, favoring the western Pacific region in the dawn hours. The pair is just 17 degrees from the Sun. As mentioned previously, this is the closest conjunction of two naked eye planets in 2017, so close the two will seem to merge to the naked eye and make a nice split with binoculars. This is also one of the first good chances to spy Mars for this apparition, fresh off of its solar conjunction on July 27th, 2017. Mars is now headed towards a favorable opposition next summer on July 27th, 2018, one that’s very nearly as favorable as the historic grand opposition of 2003.
Mars shines at magnitude +1.8 on Saturday morning with a disk 3.6” across, while Mercury shines at magnitude +0.05 with a 64% illuminated disk 6.4” across. Mars is actually 389 million km (2.6 AU) from the Earth this weekend, while Mercury is 158 million km (1.058 AU) distant.
Follow that planet, as Mars also makes a close (12′) pass near Venus on October 5th. At the eyepiece, Venus will look like it has a large moon, just like the Earth!
Think this pass is close? Stick around until August 10th, 2079 and you can actually see Mercury occult (pass in front of) Mars… our cyborg body should be ready to download our consciousness into by then.
The waning crescent Moon joins the view on Monday, September 18th, making a spectacular series of passes worldwide as it threads its way through the stellar-planetary lineup. Occultations involving the waning Moon are never as spectacular as those involving the waxing Moon, as the bright limb of the Moon leads the way for ingress instead of the dark edge. The best sight to behold will be the sudden reappearance of the planet of star (egress) from behind the waning crescent Moon’s dark limb.
First up is an occultation of Venus on September 18th centered on 00:55 UT. Unfortunately, this favors the eastern Indian Ocean at dawn, though viewers in Australia and New Zealand can watch the occultation under post dawn daytime skies. The pair is 22 degrees west of the Sun, and the Moon is two days from New during the event. Shining at magnitude -4, it’s actually pretty easy to pick out Venus near the crescent Moon in the daytime. Observers worldwide should give this a try on the 18th as well… folks are always amazed when I show them Venus in the daytime. The last time the Moon occulted Venus was September 3rd, 2016 and the two won’t cross paths again until February 16th, 2018.
Next up, the Moon occults the +1.4 magnitude star Regulus on the 18th at 4:56 UT. Observers across north-central Africa are best placed to observe this event. This is the 11th occultation of Regulus by the Moon in a series of 19, spanning December 2016 to April 2018.
The brightest star in the constellation Leo, Regulus is actually 79 light years distant.
Next up, the dwindling waning crescent Moon meets the Red Planet Mars and occults it for the western Pacific at 19:42 UT. Shining at magnitude +1.8 low in the dawn sky, Mars is currently only 3.6” in size, a far cry from its magnificent apparition next summer when it will appear 24.3” in size… very nearly the largest it can appear from the Earth.
And finally, the slim 2% illuminated Moon will occult the planet Mercury on September 18th centered on 23:21 UT.
Mercury occultations are tough, as the planet never strays very far from the Sun. The only known capture I’ve seen was out of Japan back in 2013:
This week’s occultation favors southeast Asia at dawn, and the pair is only 16 degrees west of the Sun. Mercury is gibbous 74% illuminated and 6” in size during the difficult occultation.
We just miss having a simultaneous “multiple occultation” this week. The Moon moves at the span of its half a degree size about once every hour with respect to the starry background, meaning an occultation must occur about 60 minutes apart for the Moon to cover two planets or a planet and a bright star at the same time, a rare once in a lifetime event indeed. The last time this transpired, the Moon covered Venus and Jupiter simultaneously for observers on Ascension Island on the morning of April 23rd 1998.
When is the next time this will occur? We’re crunching the numbers as we speak… watch this space!
Looking into next week, the Moon reaches New phase on Wednesday, September 20th at 5:31 UT/1:31 AM EDT, marking the start of lunation 1172. Can you spy the razor thin Moon Wednesday evening low to the west? Sighting opportunities improve on Thursday night.
Don’t miss this weekend’s dance of the planets in the early dawn sky, a great reason to rise early.
SANTEE, SOUTH CAROLINA – Witnessing ‘Totality’ during Monday’s ‘Great American Solar Eclipse’ was a truly mesmerizing experience far beyond anything I imagined and something I will never forget -That’s a sentiment shared by millions upon millions of fellow gushing spectators.
I was stationed in Santee, South Carolina, near Lake Marion and close to the centerline of Totality, along with space journalist friend and colleague Jeff Seibert. And we could not have asked for clearer skies to enjoy this awesome natural event made possible by a uniquely rare confluence of miraculous celestial mechanics.
Check out our expanding gallery of personal photos and videos as well as many more gathered from friends and colleagues herein.
Totality was mesmerizing! Although I fully hoped to see a science spectacle (weather permitting) – I wasn’t really prepared for the majesty of the ‘coronal fire’ of Totality on display in the sky that started with what seemed like a startling electric flash – – The sun was alive far beyond anything I imagined beforehand. An out of body experience truly beyond my wildest dreams.
And we really lucked out with the weather – – as the odds of good weather are apparently better near Lake Marion, local residents told me. Just 15 miles south in Saint George, SC where I held a well attended eclipse outreach event at my hotel the night before, it was sadly socked in.
Despite a less than promising weather forecast, the threatening Carolina storm clouds obscuring our sun as we awoke and got our camera gear together Monday morning, fortunately scooted away.
Just in the nick of time the rainy gray breakfast clouds miraculously parted as eclipse time approached and almost completely disappeared by lunchtime – fully an hour prior to the eclipses beginning from our viewing location in Santee; near beautiful Lake Marion, South Carolina, which intersects the heavily traveled I-95 North/South Interstate highway corridor.
Like tens of millions of others, I’ve seen several partial solar eclipses, but this was my first total solar eclipse and it did not disappoint!
And there is just no comparison between seeing a partial and a total solar eclipse – sort of like a family before and after having a baby.
A few hundred excited people from across the East Coast including some families with kids had coincidentally gathered at our Santee location by the Water Park.
At Santee, SC, we enjoyed unobstructed totality for all 2 minutes, 34 seconds – very close to the longest possible duration of 2 min 43 seconds experienced by folks congregated in Carbondale, Illinois.
Overall our eclipse experience began at 1:14:55 p.m. EDT and concluded at 4:08:01 EDT – nearly three hours.
Totality started at 2:43:42 p.m. EDT and concluded at 2:46:16 p.m. EDT.
At lunchtime it was a boiling hot, skin stinging 95+ degrees F. But barely half an hour into the eclipse and with the sun perhaps only a third covered the area noticeably cooled and darkened and the sunburn was gone.
As the eclipse deepened, the sky really darkened to the point we almost needed a flashlight and it was downright comfortable temperature wise.
I’m over the Moon so to speak and still replaying the totality event in my mind from start to finish.
You can follow along by watching this thrilling solar eclipse video produced by Jeff Seibert, and listen to the cheering crowd to get a sense of our Carolina Totality adventure:
Video Caption: Total Solar eclipse from Santee, SC on August 21, 2017. We were 4.8 miles South of the Umbra center line, and had clear weather until just before last contact. Credit: Jeff Seibert
At Santee we were 87% into the umbra with a 70 mile wide (115 km) lunar shadow path width, at 136 feet elevation above sea level.
There is just nothing like ‘Totality’ in my experience as a research scientist and journalist – working with and seeing cool science and space hardware up close.
Totality is a natural wonder of the Universe and it was an electrifying event.
At the moment that totality commenced, day turned almost instantly to night as though someone threw a light switch.
I distinctly heard crackling sounds burst through the air, akin to a thunderbolt clap at that very moment – heralding our sudden jolt to totality.
Cheers broke out. Everyone and myself were so totally in awe of totality. And the sun’s brilliant while corona suddenly became visible, alive and in motion as the solar surface was completely blocked, hidden behind our moon. So I just stared at the stunning beauty, barely able to function as a photographer.
The planet Venus quickly and suddenly and incredibly popped out brilliantly from the darkness of the daytime sky. Some stars were also visible.
You absolutely must experience this incomparable wonder of nature with you own eyeballs.
Focus on the fleeting moment.
Because in a flash of just 2.5 minutes #Eclipse2017 was gone & done!
The all natural light switch had been turned back on by mother nature herself.
If only a replay or restart were possible – someone in the crowd yelled in glee. And we all thought the same way.
Totality, like rockets and science can be addictive in a very positive way.
Furthermore, we also saw the famed partial solar crescents reflecting through trees onto the ground during the partial eclipse phases.
We very luckily enjoyed virtually perfect weather and clear blue skies for the entirely of the eclipse – from first contact, through totality and the last limb of contact of Earth’s moon covering the sun.
Only a few scattered cloud patches dotted overhead at the start and rapidly exited.
And very happily we were not alone.
The Aug. 21 ‘Total Solar ‘Eclipse Across America’ was enjoyed by tens of millions more lucky spectators, including many friends lining the solar eclipses narrow path of Totality from coast to coast.
The 70-mile-wide (115 km) swath of the Moons shadow raced across America from Oregon to South Carolina in a thrilling event that became sort of a communal experience with all the explanatory news coverage foreshadowing what was to come.
Everyone in North America was able to witness at least a partial solar eclipse, weather permitting- and many did either on there own or at special solar eclipse events organized at towns and cities at museums, parks and open spaces across the country.
12 million people live directly in the path of 2017 solar eclipse totality as it passed through 14 states.
It was the first total solar eclipse visible from the United States since Feb. 26, 1979. And it was the first such coast to coast eclipse crossing the entire continental United States in 99 years since June 8, 1918 during World War 1.
The umbra (or dark inner shadow) of the Moon moved west to east at 3000 MPH in Oregon and 1500 MPH by the time it reached our location in South Carolina.
The 2017 solar eclipse began on the west coast with the lunar shadow entering the US near Lincoln City, Oregon at 9:05 PDT, with totality beginning at 10:15 PDT, according to a NASA description.
Totality ended along the US East Coast in the coastal city of Charleston, South Carolina at 2:48 p.m. EDT. The last remnants of lunar shadow departed at 4:09 p.m. EDT. Charleston is about an hour or so east of my viewing location in Santee and folks there enjoyed stunning views too.
For as long as I live the 2017 Solar Eclipse Totality will be burned into my mind!
“I’m pretty sure it was not nearly as epic as the total eclipse. It was fun to watch with teenagers though. I think what was unique to me was that I was capturing the equivalent of a crescent sun. Did it get dark here, of course not, but there were a few minutes where the Space Coast went a bit dim. The most fun was looking for the shadows,” writes Julia Bergeron from Port Canaveral, FL.
Watch for Ken’s continuing onsite Minotaur IV ORS-5, TDRS-M, CRS-12 and NASA and 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.
Learn more about the 2017 Total Solar Eclipse, upcoming Minotaur IV ORS-5 military launch on Aug. 25, recent ULA Atlas TDRS-M NASA comsat on Aug. 18, 2017 , SpaceX Dragon CRS-12 resupply launch to ISS on Aug. 14, NASA missions and more at Ken’s upcoming outreach events at Kennedy Space Center Quality Inn, Titusville, FL:
Aug 24-26: “2017 Total Solar Eclipse Minotaur IV ORS-5, TDRS-M NASA comsat, SpaceX CRS-12 resupply launches to the ISS, Intelsat35e, BulgariaSat 1 and NRO Spysat, SLS, Orion, Commercial crew capsules from Boeing and SpaceX , Heroes and Legends at KSCVC, ULA Atlas/John Glenn Cygnus launch to ISS, SBIRS GEO 3 launch, GOES-R weather satellite launch, OSIRIS-Rex, Juno at Jupiter, InSight Mars lander, SpaceX and Orbital ATK cargo missions to the ISS, ULA Delta 4 Heavy spy satellite, Curiosity and Opportunity explore Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings
“Astonished at the vivacity and brightness of the corona, and the contrast with the infinitely dark moon. Through binos it almost had me in tears,” writes John Gould from Red Bank, SC.
Human space exploration is going to kick into high gear in the coming decades. Within the inner Solar System alone, missions are being planned that will see robotic explorers and crews sent to Near Earth Objects (NEOs), back to the Moon, and even on to Mars. Beyond that, there are even plans to send robotic missions to Europa, Enceladus, Titan, and other “ocean worlds” to look for signs of life.
In all cases, questions natural arise as to what kinds of missions will be most suited to them. In the case of places like Titan (which have low gravity and dense atmospheres) aerial drones are considered the best bet. But when it comes to rocky place like asteroids, the Moon and Mars, the best candidate may be robot snakes, which could find their way through tight spaces and travel underground.
This concept was proposed three years ago by the Foundation for Scientific and Industrial Research (SINTEF), the largest independent research organization in Scandinavia. As part of a project commissioned by the ESA – known as SERPEX – they began studying how robots designed to mimic the movements of snakes could assist astronauts aboard the International Space Station.
But as Aksel Transeth, a senior research scientist at SINTEF, explained in a recent press statement, the possibilities go far beyond the ISS:
“More ambitious applications include potential activities on comets and the Moon. [A] Snake Robot that can assist ISS astronauts in maintaining their equipment is perhaps a solution which can be possible to realize on a more short term.”
Compared to other robotic explorers, the main selling point of a robot snake is that it offers better mobility. For two decades now, NASA has been exploring the Red Planet with robotic rovers, starting with Pathfinder and Sojourner in 1997, Spirit and Opportunity in 2003, and then Curiosity in 2012. And in a little over two years, they will be sending the Mars 2020 rover.
In all cases, these robots get around on six wheels and conduct experiments using instruments on robotic arms. But as the missions teams behind these rovers have learned, mobility can be a challenge. For instance, after five years on the Martian surface, the Spirit rover became stuck in soft soil, where its mission ended. And as successful as these missions have been at conducting research, there are locations that they simply can’t get to.
The SINTEF researchers decided to tackle these issues through biomimicry – i.e. robots that mimic the functions of living creatures. By combining a rover that can navigate over large distances with a snake robot that can crawl along the ground and get into inaccessible places, they believe that future missions would be able to go places and collect samples in ways that other missions could not.
As Transeth explained back in 2013, this pairing would open up all kinds of possibilities. “We are looking at several alternatives to enable a rover and a robot to work together,” he said. “Since the rover has a powerful energy source, it can provide the snake robot with power through a cable extending between the rover and the robot. If the robot had to use its own batteries, it would run out of power and we would lose it.”
In the configuration Transeth and his colleagues are envisioning, the rover would handle the task of traveling over long distances and then be able to dispatch the snake to crawl into tight inaccessible areas. They would be connected by a cable that would provide electricity, communication signals and would be used to pull the snake back in. In this sense, the snake would act like one of the rover’s arms, but would have the ability to travel autonomously.
“We believe that we can design a robot that can hold on, roll itself up and then extend its body in order to reach new contact points,” said Transeth. “Moreover, we believe that it can creep in among equipment components on the ISS and use equipment surfaces to gain traction in order to keep moving forward – much in the same way as real snakes do in the wild.”
On Mars, sample collection is crucial to many space agency’s research. For the Curiosity rover, the presence of hydrated minerals and clays in soil samples confirmed that Mars once had a warmer, wetter climate. And in the future, scientists hope to find biomakers in Martian soil that could indicate the presence (past or present) of biological life. In this respect, a snake robot would prove very useful since it could access underground recesses the rover cannot.
On the Moon, snake robots could be especially useful in helping the ESA establish it’s proposed “Moon Village” – a permanent base for scientific activity, tourism and mining that would also act as a successor to the ISS. The most likely location for this base could be within stable lava tubes or subterranean tunnels, which would provide natural shielding from meteors, solar radiation and cosmic rays.
But before such construction of this base can take place, these tunnels and lava tubes will have to be inspected to ensure that they are safe for human habitation. The ESA has also been committed to studying comets in recent years, which included sending the Rosetta space probe and Philae lander to rendezvous with the comet 67P/Tsjurjumov–Gerasimenko in 2014.
Unfortunately, the lander experienced problems when its system of harpoons (designed to hold it in place) failed to deploy. As a result, it was forced to make another soft landing which left it in a position and location that was not optimal for research. In the future, the ESA could get avoid this by sending a probe to the surface that would deploy the snakes to the surface, which could then burrow into the comet’s interior.
But in the meantime, operations aboard the ISS remain the most realistic and likely application for these robots. Here, astronauts are engaged in ongoing scientific experiments, but are also responsible for maintaining the station and all of its equipment. In this latter respect, the SERPEX project could certainly prove useful, providing them with robot helpers that could help with the regular maintenance.
“It’s possible that a robot could carry out some of the routine inspection and maintenance work,” said Transeth. “The experiments are stacked in the shelf sections, behind which corrosion can occur. To find this out, inspections have to be made. A snake robot could creep behind the sections, carry out an inspection, and perhaps even perform small maintenance tasks.”
Some of the concepts developed by SINTEF so far include the Aiko robot, which was developed to produce a portable system for experimenting with snake robot locomotion. The robot consists of several identical joint modules with two motorized degrees of freedom each. As you can see from the video above, it is propelled by contact forces between the robot and the obstacles in its way.
But of course, developing snake robots that can handle various tasks while working in different environments – ranging from working in micro-gravity aboard the ISS to snaking their way through tunnels on a body with gravity – presents many challenges. And in the coming years, Transeth and his colleagues will be looking for ways to address all of them.
“We want to find out what specifications a snake robot system requires,” he said. “For example, what kind of sensors does the robot need to obtain an adequate understand its surroundings? What technologies are available to help us meet these needs, and what new technologies will have to be developed? What uncertainties are involved in terms to what it may be possible to achieve?”
Already, astronauts aboard the ISS have robotic helpers in the form of the Synchronized Position Hold Engage and Reorient Experimental Satellite (SPHERES). These free flying satellites serve as test beds for a diverse range of hardware and software, all of which is critical for future space missions that use distributed spacecraft architecture.
Soon enough, they will be replaced by a drone called Astrobee – a robotic cube packed with sensors, cameras, computers, and a propulsion system. The brainchild of the Ames Research Center’s Intelligent Robotics Group, this drone will be flying around the ISS and making inspections.
Some of the technology used by Astrobee will be similar to what Transeth and his colleague are hoping to apply to their snake robot system. As such, they hope to learn much from this drone’s time aboard the ISS and incorporate the lessons that are learned from it.
In February of 2015, the National Observatory of Athens and the European Space Agency launched theNear-Earth object Lunar Impacts and Optical TrAnsients (NELIOTA) project. Using the 1.2 meter telescope at the Kryoneri Observatory, the purpose of this project is to the determine the frequency and distribution of Near-Earth Objects (NEOs) by monitoring how often they impact the Moon.
Last week, on May 24th, 2017, the ESA announced that the project had begun to detect impacts, which were made possible thanks to the flashes of light detected on the lunar surface. Whereas other observatories that monitor the Moon’s surface are able to detect these impacts, NELIOTA is unique in that it is capable of not only spotting fainter flashes, but also measuring the temperatures of they create.
Projects like NELIOTA are important because the Earth and the Moon are constantly being bombarded by natural space debris – which ranges in size from dust and pebbles to larger objects. While larger objects are rare, they can cause considerable damage, like the 20-meter object that disintegrated above the Russian city of Chelyabinsk in February of 2013, causing extensive injuries and destruction of property.
What’s more, whereas particulate matter rains down on Earth and the Moon quite regularly, the frequency of pebble-sized or meter-sized objects is not well known. These objects remain too small to be detected by telescopes directly, and cameras are rarely able to picture them before they break up in Earth’s atmosphere. Hence, scientists have been looking for other ways to determine just how frequent these potentially-threatening objects are.
One way is to observe the areas of the lunar surface that are not illuminated by the Sun, where the impact of a small object at high speed will cause a bright flash. These flashes are created by the object burning up on impact, and are bright enough to be seen from Earth. Assuming the objects have a density and velocity common to NEOs, the brightness of the impact can be used to determine the size and mass of the object.
“These observations are very relevant for our Space Situational Awareness program. In particular, in the size range we can observe here, the number of objects is not very well known. Performing these observations over a longer period of time will help us to better understand this number.“
After being taken offline in 2016 for the sake of making upgrades, the NELIOTA project officially began conducting operations on March 8th, 2017. Using this refurbished telescope, which is operated by the National Observatory of Athens, NELIOTA is capable of detecting flashes that are much fainter than any current, small-aperture, lunar monitoring telescopes.
The telescope does this by observing the Moon’s night hemisphere whenever it is above the horizon and between phases. At these times – i.e. between a New Moon and the First Quarter, or between the Last Quarter and a New Moon – the surface is mostly dark and flashes are most visible. Incoming light is then split into two colors and the data is recorded by two advanced digital cameras that operate in different color ranges.
This data is then analyzed by automated software, which extrapolates temperatures based on the color data obtained by the cameras. As Alceste Bonanos – the Principal Investigator for NELIOTA – explained, all this sets the 1.2 meter telescope apart:
“Its large telescope aperture enables NELIOTA to detect fainter flashes than other lunar monitoring surveys and provides precise color information not currently available from other project. Our twin camera system allows us to confirm lunar impact events with a single telescope, something that has not been done before. Once data have been collected over the 22-month long operational period, we will be able to better constrain the number of NEOs (near-Earth objects) in the decimetre to metre size range.
The NELIOTA project scientists are currently collaborating with the Science Support Office of ESA to analyze the flashes and measure the temperatures of each flash. From this, they hope to be able to make accurate estimates of the mass and size of each impactor, which they will further corroborate by analyzing the size of the craters these impacts leave behind.
The study of impacts on the Moon will ultimately let scientists know exactly how often larger objects are raining down on Earth. Armed with this information, we will be able to make better predictions on when and how a potentially-threatening object could be entering our atmosphere. As the Chelyabinsk meteor demonstrated, one of the greatest dangers posed by meteorites is a general lack of preparedness. Where people can be forewarned, injury, damage and even deaths can be prevented.
NELIOTA is also contributing to public outreach and education through a number of initiatives. These include public tours of the Kryoneri Observatory – in which the details of the NELIOTA project are shared – as well as presentations to students and the general public about Near-Earth Asteroids. The project team are also training two PhD students in how to operate the Kryoneri telescope and conduct lunar observing, thus creating the next-generation of NEO observers.
This summer (Friday, June 30th), the Observatory will also be hosting a public event to coincide with Asteroid Day 2017. This international event will feature presentations, speeches and educational seminars hosted by astronomical institutions and organizations from all around the world. Save the date!
There’s a new type of planet in town, though you won’t find it in well-aged solar systems like our own. It’s more of a stage of formation that planets like Earth can go through. And its existence helps explain the relationship between Earth and our Moon.
The new type of planet is a huge, spinning, donut-shaped mass of hot, vaporized rock, formed as planet-sized objects smash into each other. The pair of scientists behind the study explaining this new planet type have named it a ‘synestia.’ Simon Lock, a graduate student at Harvard University, and Sarah Stewart, a professor in the Department of Earth and Planetary Sciences at the University of California, Davis, say that Earth was at one time a synestia.
The current theory of planetary formation goes like this: When a star forms, the left-over material is in motion around the star. This left-over material is called a protoplanetary disk. The material coagulates into larger bodies as the smaller ones collide and join together.
As the bodies get larger and larger, the force of their collisions becomes greater and greater, and when two large bodies collided, their rocky material melts. Then, the newly created body cools, and becomes spherical. It’s understood that this is how Earth and the other rocky planets in our Solar System formed.
Lock and Stewart looked at this process and asked what would happen if the resulting body was spinning quickly.
When a body is spinning, the law of conservation of angular momentum comes into play. That law says that a spinning body will spin until an external torque slows it down. The often-used example from figure skating helps explain this.
If you’ve ever watched figure skaters, and who hasn’t, their actions are very instructive. When a single skater is spinning rapidly, she stretches out her arms to slow the rate of spin. When she folds her arms back into her body, she speeds up again. Her angular momentum is conserved.
This short video shows figure skaters and physics in action.
If you don’t like figure skating, this one uses the Earth to explain angular momentum.
Now take the example from a pair of figure skaters. When they’re both turning, and the two of them join together by holding each other’s hands and arms, their angular momentum is added together and conserved.
Replace two figure skaters with two planets, and this is what the two scientists behind the study wanted to model. What would happen if two large bodies with high energy and high angular momentum collided with each other?
If the two bodies had high enough temperatures and high enough angular momentum, a new type of planetary structure would form: the synestia. “We looked at the statistics of giant impacts, and we found that they can form a completely new structure,” Stewart said.
“We looked at the statistics of giant impacts, and we found that they can form a completely new structure.” – Professor Sarah Stewart, Department of Earth and Planetary Sciences at the University of California, Davis.
As explained in a press release from the UC Davis, for a synestia to form, some of the vaporized material from the collision must go into orbit. When a sphere is solid, every point on it is rotating at the same rate, if not the same speed. But when some of the material is vaporized, its volume expands. If it expands enough, and if its moving fast enough, it leaves orbit and forms a huge disc-shaped synestia.
Other theories have proposed that two large enough bodies could form an orbiting molten mass after colliding. But if the two bodies had high enough energy and temperature to vaporize some of the rock, the resulting synestia would occupy a much larger space.
“The main issue with looking for synestias around other stars is that they don’t last a long time. These are transient, evolving objects that are made during planet formation.” – Professor Sarah Stewart, UC Davis.
These synestias likely wouldn’t last very long. They would cool quickly and condense back into rocky bodies. For a body the size of Earth, the synestia might only last one hundred years.
The synestia structure sheds some light on how moons are formed. The Earth and the Moon are very similar in terms of composition, so it’s likely they formed as a result of a collision. It’s possible that the Earth and Moon formed from the same synestia.
These synestias have been modelled, but they haven’t been observed. However, the James Webb Space Telescope will have the power to peer into protoplanetary disks and watch planets forming. Will it observe a synestia?
“These are transient, evolving objects that are made during planet formation.” – Professor Sarah Stewart, UC Davis
In an email exchange with Universe Today, Dr. Sarah Stewart of UC Davis, one of the scientists behind the study, told us that “The main issue with looking for synestias around other stars is that they don’t last a long time. These are transient, evolving objects that are made during planet formation.”
“So the best bet for finding a rocky synestia is young systems where the body is close to the star. For gas giant planets, they may form a synestia for a period of their formation. We are getting close to being able to image circumplanetary disks in other star systems.”
Once we have the ability to observe planets forming in their circumstellar disks, we may find that synestias are more common than rare. In fact, planets may go through the synestia stage multiple times. Dr. Stewart told us that “Based on the statistics presented in our paper, we expect that most (more than half) of rocky planets that form in a manner similar to Earth became synestias one or more times during the giant impact stage of accretion.”
Besides Earth, Saturn may be the only other planet where you can order rings with a side of ravioli. Closeup photos taken by the Cassini probe of the the planet’s second-innermost moon, Pan, on March 7 reveal remarkable new details that have us grasping at food analogies in a feeble attempt to describe its unique appearance.
The two-part structure of the moon is immediately obvious: a core body with a thin, wavy ridge encircling its equator. How does such a bizarre object form in the first place? There’s good reason to believe that Pan was once part of a larger satellite that broke up near Saturn long ago. Much of the material flattened out to form Saturn’s rings while large shards like Pan and another ravioli lookalike, Atlas, orbited within or near the rings, sweeping up ring particles about their middles. Tellingly, the ridges are about as thick as the vertical distances each satellite travels in its orbit about the planet.
Today, Pan orbits within and clears the narrow Encke Gap in Saturn’s outer A-ring of debris. It also helps create and shape the narrow ringlets that appear in the gap It’s lookalike cousin Atlas orbits just outside the A-ring.
Moons embedded in rings can have profound effects on that material from clearing gaps to creating new temporary ringlets and raising vertical waves of material that rise above and below the ring plane. All these effects are produced by gravity, which gives even small objects like Pan dominion over surprisingly vast regions.
PORT CANAVERAL – Bit by bit, piece by piece, the first of NASA’s SLS megarockets designed to propel American astronauts on deep space missions back to the Moon and beyond to Mars is at last coming together on the Florida Space Coast. And the first big integrated piece of actual flight hardware – the powerful second stage named the Interim Cryogenic Propulsion Stage (ICPS) – has just arrived by way of barge today (Mar. 7) at Port Canaveral, Fl.
The ICPS will propel NASA’s new Orion crew capsule on its maiden uncrewed mission around the Moon – currently slated for blastoff on the inaugural SLS monster rocket on the Exploration Mission-1 (EM-1) mission late next year.
SLS-1/Orion EM-1 will launch from pad 39B at NASA’s Kennedy Space Center in late 2018. The SLS will be the most powerful rocket in world history.
The SLS upper stage – designed and built by United Launch Alliance (ULA) and Boeing – arrived safely by way of the specially-designed ship called the Delta Mariner early Tuesday morning, Mar. 7, into the channel of Port Canaveral, Florida – as witnessed by this author.
“We are proud to be working with The Boeing Company and NASA to further deep space exploration!” ULA said in a statement.
Major assembly of the ICPS was completed at ULA’s Decatur, Alabama, manufacturing facility in December 2016.
The ICPS is the designated upper stage for the first maiden launch of the initial Block 1 version of the SLS.
It is based on ULA’s Delta Cryogenic Second Stage which has successfully flown numerous times on the firm’s Delta IV family of rockets.
In the event that NASA decides to add a two person crew to the EM-1 mission, Bill Hill, NASA’s deputy associate administrator for Exploration Systems Development in Washington, D.C., stated that the agency would maintain the Interim Cryogenic Propulsion stage for the first flight, and not switch to the more advanced and powerful Exploration Upper Stage (EUS) planned for first use on the EM-2 mission.
The ICPS was loaded onto the Delta Mariner and departed Decatur last week to began its sea going voyage of more than 2,100 miles (3300 km). The barge trip normally takes 8 to 10 days.
“ULA has completed production on the interim cryogenic propulsion stage (ICPS) flight hardware for NASA’s Space Launch System and it’s on the way to Cape Canaveral aboard the Mariner,” ULA noted in a statement last week.
The 312-foot-long (95-meter-long) ULA ship docked Tuesday morning at the wharf at Port Canaveral to prepare for off loading from the roll-on, roll-off vessel.
The Delta Mariner can travel on both rivers and open seas and navigate in waters as shallow as nine feet.
“ICPS, the first integrated SLS hardware to arrive at the Cape, will provide in-space propulsion for the SLS rocket on its Exploration Mission-1 (EM-1) mission,” according to ULA.
The next step for the upper stage is ground transport to United Launch Alliance’s Delta IV Operation Center on Cape Canaveral Air Force Station in Florida for further testing and processing before being moved to the Kennedy Space Center.
ULA will deliver the ICPS to NASA in mid-2017.
“It will be the first integrated piece of SLS hardware to arrive at the Cape and undergo final processing and testing before being moved to Ground Systems Development Operations at NASA’s Kennedy Space Center,” said NASA officials.
“The ICPS is a liquid oxygen/liquid hydrogen-based system that will provide the thrust needed to send the Orion spacecraft and 13 secondary payloads beyond the moon before Orion returns to Earth.”
The upper stage is powered by a single RL-10B-2 engine fueled by liquid hydrogen and oxygen and generates 24,750 pounds of thrust. It measures 44 ft 11 in (13.7 m ) in length and 16 ft 5 in (5 m) in width.
All major elements of the SLS will be assembled for flight inside the high bay of NASA’s iconic Vehicle Assembly Building which is undergoing a major overhaul to accommodate the SLS. The VAB high bay was extensively refurbished to convert it from Space Shuttle to SLS assembly and launch operations.
For SLS-1 the mammoth booster will launch in its initial 70-metric-ton (77-ton) Block 1 configuration with a liftoff thrust of 8.4 million pounds – more powerful than NASA’s Saturn V moon landing rocket.
Components of the SLS-1 rocket are being manufactured at NASA’s Michoud Assembly Facility and elsewhere around the country by numerous suppliers.
Michoud is building the huge liquid oxygen/liquid hydrogen SLS core stage fuel tank, derived from the Space Shuttle External Tank (ET) – as I detailed here.
The ICPS sits on top of the SLS core stage.
The next Delta IV rocket launching with a Delta Cryogenic Second Stage is tentatively slated for March 14 from pad 37 at the Cape.
The Orion EM-1 capsule is currently being manufactured at the Neil Armstrong Operations and Checkout Building at the Kennedy Space Center by prime contractor Lockheed Martin.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.