Mining asteroids might be necessary for humanity to expand into the Solar System. But what effect would asteroid mining have on the world's economy? Credit: ESA.
Yesterday (on May 8th, 2017), an asteroid swung past Earth on its way towards the Sun. This Near Earth Object (NEO), known as 2017 HX4, measures between 10 and 33 meters (32.8 and 108 feet) and made its closest approach to Earth at 11:58 am UT (7:58 am EDT; 4:58 am PT). Naturally, there were surely those who wondered if this asteroid would hit us and trigger a terrible cataclysm!
But of course, like most NEOs that periodically make a close pass to Earth, 2017 HX4 passed us by at a very safe distance. In fact, the asteroid’s closest approach to Earth was estimated to be at a distance of 3.7 Lunar Distances (LD) – i.e. almost four times the distance between the Earth and the Moon. This, and other pertinent information was tweeted in advance by the International Astronomical Union’s Minor Planet Center (IAU MPC) on April 29th.
This object was first spotted on April 26th, 2017, using the 1.8 meter Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), located at the summit of Haleakala in Hawaii. Since that time, it has been monitored by multiple telescopes around the world, and its tracking data and information about its orbit and other characteristics has been provided by the IAU MPC.
Interactive Orbit Sketch, showing the orbit of the Near Earth Object (NEO) known as 2017 HX4. Credit: IAU MPC
With funding provided by NASA’s Near-Earth Object Observations program, the IAU MPC maintains a centralized database that is responsible for the identification, designation and orbit computations of all the minor planets, comets and outer satellites of the Solar System. Since it’s inception, it has been maintaining information on 16,202 Near-Earth Objects, 729,626 Minor Planets, and 3,976 comets.
But it is the NEOs that are of particular interest, since they periodically make close approaches to Earth. In the case of 2017 HX4, the object has been shown to have an orbital period of 2.37 years, following a path that takes it from beyond the orbit of Venus to well beyond the orbit of Mars. In other words, it orbits our Sun at an average distance (semi-major axis) of 1.776 AU, ranging from about 0.88 AU at perihelion to 2.669 AU at aphelion.
PS1 at dawn. The mountain in the distance is Mauna Kea, about 130 kilometers southeast. Credit: pan-starrs.ifa.hawaii.edu
From these combined observations, the IAU MPC was able to compile information on the object’s orbital period, when it would cross Earth’s orbit, and just how close it would come to us in the process. So, as always, there was nothing to worry about here folks. These objects are always spotted before they cross Earth’s orbit, and their paths, periods and velocities and are known about in advance.
Even so, it’s worth noting that an object of this size was nowhere near to be large enough to cause an Extinction Level Event. In fact, the asteroid that struck Earth 65 millions year ago at the end of Cretaceous era – which created the Chicxulub Crater on the Yucatan Peninsula in Mexico and caused the extinction of the dinosaurs – was estimated to measure 10 km across.
At 10 to 33 meters (32.8 to 108 feet), this asteroid would certainly have caused considerable damage if it hit us. But the results would not exactly have been cataclysmic. Still, it might not be too soon to consider getting off this ball of rock. You know, before – as Hawking has warned – a single event is able to claim all of humanity in one fell swoop!
The MPC is currently tracking the 13 NEOs that were discovered during the month of May alone, and that’s just so far. Expect to hear more about rocks that might cross our path in the future.
The night sky, is the night sky, is the night sky. The constellations you learned as a child are the same constellations that you see today. Ancient people recognized these same constellations. Oh sure, they might not have had the same name for it, but essentially, we see what they saw.
But when you see animations of galaxies, especially as they come together and collide, you see the stars buzzing around like angry bees. We know that the stars can have motions, and yet, we don’t see them moving?
How fast are they moving, and will we ever be able to tell?
Stars, of course, do move. It’s just that the distances are so great that it’s very difficult to tell. But astronomers have been studying their position for thousands of years. Tracking the position and movements of the stars is known as astrometry.
We trace the history of astrometry back to 190 BC, when the ancient Greek astronomer Hipparchus first created a catalog of the 850 brightest stars in the sky and their position. His student Ptolemy followed up with his own observations of the night sky, creating his important document: the Almagest.
Printed rendition of a geocentric cosmological model from Cosmographia, Antwerp, 1539. Credit: Wikipedia Commons/Fastfission
In the Almagest, Ptolemy laid out his theory for an Earth-centric Universe, with the Moon, Sun, planets and stars in concentric crystal spheres that rotated around the planet. He was wrong about the Universe, of course, but his charts and tables were incredibly accurate, measuring the brightness and location of more than 1,000 stars.
A thousand years later, the Arabic astronomer Abd al-Rahman al-Sufi completed an even more detailed measurement of the sky using an astrolabe.
One of the most famous astronomers in history was the Danish Tycho Brahe. He was renowned for his ability to measure the position of stars, and built incredibly precise instruments for the time to do the job. He measured the positions of stars to within 15 to 35 arcseconds of accuracy. Just for comparison, a human hair, held 10 meters away is an arcsecond wide.
Also, I’m required to inform you that Brahe had a fake nose. He lost his in a duel, but had a brass replacement made.
In 1807, Friedrich Bessel was the first astronomer to measure the distance to a nearby star 61 Cygni. He used the technique of parallax, by measuring the angle to the star when the Earth was on one side of the Sun, and then measuring it again 6 months later when the Earth was on the other side.
With parallax technique, astronomers observe object at opposite ends of Earth’s orbit around the Sun to precisely measure its distance. Credit: Alexandra Angelich, NRAO/AUI/NSF.
Over the course of this period, this relatively closer star moves slightly back and forth against the more distant background of the galaxy.
And over the next two centuries, other astronomers further refined this technique, getting better and better at figuring out the distance and motions of stars.
But to really track the positions and motions of stars, we needed to go to space. In 1989, the European Space Agency launched their Hipparcos mission, named after the Greek astronomer we talked about earlier. Its job was to measure the position and motion of the nearby stars in the Milky Way. Over the course of its mission, Hipparcos accurately measured 118,000 stars, and provided rough calculations for another 2 million stars.
That was useful, and astronomers have relied on it ever since, but something better has arrived, and its name is Gaia.
Launched in December 2013, the European Space Agency’s Gaia in is in the process of mapping out a billion stars in the Milky Way. That’s billion, with a B, and accounts for about 1% of the stars in the galaxy. The spacecraft will track the motion of 150 million stars, telling us where everything is going over time. It will be a mind bending accomplishment. Hipparchus would be proud.
With the most precise measurements, taken year after year, the motions of the stars can indeed be calculated. Although they’re not enough to see with the unaided eye, over thousands and tens of thousands of years, the positions of the stars change dramatically in the sky.
The familiar stars in the Big Dipper, for example, look how they do today. But if you go forward or backward in time, the positions of the stars look very different, and eventually completely unrecognizable.
When a star is moving sideways across the sky, astronomers call this “proper motion”. The speed a star moves is typically about 0.1 arc second per year. This is almost imperceptible, but over the course of 2000 years, for example, a typical star would have moved across the sky by about half a degree, or the width of the Moon in the sky.
A 20 year animation showing the proper motion of Barnard’s Star. Credit: Steve Quirk, images in the Public Domain.
The star with the fastest proper motion that we know of is Barnard’s star, zipping through the sky at 10.25 arcseconds a year. In that same 2000 year period, it would have moved 5.5 degrees, or about 11 times the width of your hand. Very fast.
When a star is moving toward or away from us, astronomers call that radial velocity. They measure this by calculating the doppler shift. The light from stars moving towards us is shifted towards the blue side of the spectrum, while stars moving away from us are red-shifted.
Between the proper motion and redshift, you can get a precise calculation for the exact path a star is moving in the sky.
Credit: ESA/ATG medialab
We know, for example, that the dwarf star Hipparcos 85605 is moving rapidly towards us. It’s 16 light-years away right now, but in the next few hundred thousand years, it’s going to get as close as .13 light-years away, or about 8,200 times the distance from the Earth to the Sun. This won’t cause us any direct effect, but the gravitational interaction from the star could kick a bunch of comets out of the Oort cloud and send them down towards the inner Solar System.
The motions of the stars is fairly gentle, jostling through gravitational interactions as they orbit around the center of the Milky Way. But there are other, more catastrophic events that can make stars move much more quickly through space.
When a binary pair of stars gets too close to the supermassive black hole at the center of the Milky Way, one can be consumed by the black hole. The other now has the velocity, without the added mass of its companion. This gives it a high-velocity kick. About once every 100,000 years, a star is kicked right out of the Milky Way from the galactic center.
A rogue star being kicked out of a galaxy. Credit: NASA, ESA, and G. Bacon (STScI)
Another situation can happen where a smaller star is orbiting around a supermassive companion. Over time, the massive star bloats up as supergiant and then detonates as a supernova. Like a stone released from a sling, the smaller star is no longer held in place by gravity, and it hurtles out into space at incredible speeds.
Astronomers have detected these hypervelocity stars moving at 1.1 million kilometers per hour relative to the center of the Milky Way.
All of the methods of stellar motion that I talked about so far are natural. But can you imagine a future civilization that becomes so powerful it could move the stars themselves?
In 1987, the Russian astrophysicist Leonid Shkadov presented a technique that could move a star over vast lengths of time. By building a huge mirror and positioning it on one side of a star, the star itself could act like a thruster.
An example of a stellar engine using a mirror and a Dyson Swarm. Credit: Vedexent at English Wikipedia (CC BY-SA 3.0)
Photons from the star would reflect off the mirror, imparting momentum like a solar sail. The mirror itself would be massive enough that its gravity would attract the star, but the light pressure from the star would keep it from falling in. This would create a slow but steady pressure on the other side of the star, accelerating it in whatever direction the civilization wanted.
Over the course of a few billion years, a star could be relocated pretty much anywhere a civilization wanted within its host galaxy.
This would be a true Type III Civilization. A vast empire with such power and capability that they can rearrange the stars in their entire galaxy into a configuration that they find more useful. Maybe they arrange all the stars into a vast sphere, or some kind of geometric object, to minimize transit and communication times. Or maybe it makes more sense to push them all into a clean flat disk.
Amazingly, astronomers have actually gone looking for galaxies like this. In theory, a galaxy under control by a Type III Civilization should be obvious by the wavelength of light they give off. But so far, none have turned up. It’s all normal, natural galaxies as far as we can see in all directions.
For our short lifetimes, it appears as if the sky is frozen. The stars remain in their exact positions forever, but if you could speed up time, you’d see that everything is in motion, all the time, with stars moving back and forth, like airplanes across the sky. You just need to be patient to see it.
Composite image taken at Mount Bromo in Indonesia during the peak night of Eta Aquarid meteor shower. Credit and copyright: Justin Ng.
An Eta Aquarid meteor captured on video by astrophotographer Justin Ng shows an amazing explodingred meteor and what is known as a persistent train — what remains of a meteor fireball in the upper atmosphere as winds twist and swirl the expanding debris.
The meteor pierced through the clouds and the vaporized “remains” of the fireball persisted for over 10 minutes, Justin said. It lasts just a few seconds in the time-lapse.
Here’s the video:
Justin took this footage during an astrophotography tour to Mount Bromo in Indonesia, where he saw several Eta Aquarid meteors. The red, explody meteor occurred at around 4:16 am,local time. The Small Magellanic Cloud is also visible just above the horizon on the left.
Eta Aquarid meteor piercing through cloud and left behind a red smoke trail that lasted for over 10mins. Taken in Mt. Bromo 8hrs ago. pic.twitter.com/WtFl9TGRbj
Persistent trains occur when a meteoroid blasts through the air, ionizes gases in our atmosphere. Until recently, these have been difficult to study because they are rather elusive. But lately, with the widespread availability of ultra-fast lenses and highly sensitive cameras, capturing these trains is becoming more common, much to the delight of astrophotography fans!
Mount Bromo, 2,329 meters (7600 ft.) high is an active volcano in East Java, Indonesia.
Discovered on March 15th, 2015 by the prolific PanSTARRS-1 NEO survey atop Haleakala in Maui, Hawaii, Comet ER61 PanSTARRS made our who’s-who list of bright comets to watch for in 2017. The odd “ER61” designation stems from the early identification of the object as an asteroid, before it presented observers with a cometary appearance.
The path of Comet C/2015 ER61 PanSTARRS through the sky from early May through mid-August. Credit: Starry Night Education software.
Late northern hemisphere Spring through Summer sees the comet maintaining a decent elevation above the eastern horizon at dawn, gliding north and parallel to the ecliptic plane through the constellations Pisces, Aries and Taurus from May through mid-August. The comet passed 1.08 AU from the Earth last month on April 4th, and is now racing away from us. The comet’s location near the March equinoctial point on the celestial hemisphere assures an equally good apparition for both the northern and southern hemisphere. As seen from latitude 30 degrees north, the comet sits 30 degrees above the eastern horizon, through the remainder of May. Venus also makes a brilliant beacon to track down Comet ER61 PanSTARRS, as the planet heads towards greatest elongation 46 degrees west of the Sun on June 3rd.
The orbit of Comet ER61 PanSTARRS through the inner solar system. Credit: NASA/JPL.
The comet is also on a 7,591 year long orbit inbound, which takes it out nearly 2,500 AU from the Sun. That’s 190 times the Pluto-Sun distance, and the fourth most distant aphelion of any solar system object known. The 2015-2017 passage of the comet through the inner solar system actually shortened the orbit of Comet ER61 PanSTARRS down to an aphelion of ‘only’ 854 AU due to a 0.9 AU pass near Jupiter last year on March 28th, 2016. A similar orbital shortening by Jove occurred for Comet Hale-Bopp in 1996, which came in on an 4,200 year orbit and departed the inner solar system on a shorter 2,500 year path around the Sun.
The projected light curve for Comet C/2015 ER51 PanSTARRS. The purple line denotes perihelion, and the black dots are actual observations. Adapted from Seiichii Yoshida’s Weekly Information for Bright Comets.
Prospects and Prognostications
Observers reported an outburst from the comet last month in the first week of April, causing it to jump about 2 magnitudes in brightness. Right now, it’s holding steady at +7th magnitude. Unfortunately, the Moon reaches Full phase this week on May 10th, though you’ve still got a slim window to hunt for the comet after Moonset and before sunrise. Once the Moon moves towards a slender crescent phase next late week, we’ll once again have dark predawn skies ideal for comet hunting.
Here are some key dates for Comet C/2015 ER61 PanSTARRS as it glides through the dawn sky:
(Stars highlighted are brighter than +5th magnitude, and passes are less than a degree unless otherwise noted.)
May 10th: Reaches perihelion at 1.04 astronomical units (AU) from the Sun.
May 12th: Passes near the +4.9 magnitude star 19X Piscium.
May 20-23rd: Passes less than 10 degrees from Venus.
May 21st: The waning crescent Moon passes less than 10 degrees to the south.
June 10th: Passes near the +3.6 magnitude star Eta Piscium.
June 11th: Passes near the galaxy M74.
June 16th: Passes into the constellation Aries.
June 19th: The waning crescent Moon passes 9 degrees to the south.
July 13th: Passes near (less than 5′) the +4.6 magnitude star Epsilon Arietis.
July 18th: The waning crescent Moon passes 9 degrees to the south.
July 23rd: Passes near the +4.8 star Zeta Arietis.
The comet versus Venus in the dawn sky – looking eastward on May 15th. Credit: Stellarium.
August 2nd: Crosses into the constellation Taurus.
August 15th: The waning crescent Moon passes 8 degrees to the south.
August 16th: Passes near M45 (The Pleiades)
After mid-August, Comet 2015 ER61 PanSTARRS will drop back down below +10th magnitude, not to return for several millennia to come.
Observing a comet like ER61 PanSTARRS is as simple as knowing where and when to look, then starting to slowly sweep the suspect area with binoculars for a little fuzzball looking like a globular cluster stubbornly refusing to snap into focus. In pre-telescopic times, ER61 PanSTARRS would’ve entered and exited the inner solar system unrecorded.
Comet C/2015 ER61 PanSTARRS from April 12th. Image credit and copyright: Joseph Brimacombe.
Next up: We’ve got one more predicted comet on tap for 2017, as C/2015 V2 Johnson brightens up to +7th magnitude in mid-June. Keep watching the skies, as the next great comet of the century could always appear unannounced at any time.
Image of the open star cluster Messier 41, highlighting its combination of red dwarf, white dwarf and K3-type class stars. Credit: Wikisky
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the double star known as Messier 41. Enjoy!
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 them so that 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 the open star cluster known as Messier 41 (aka. M41, NGC 2287). Located in the Canis Major constellation – approximately 4,300 light years from Earth – this cluster lies just four degrees south of Sirius, the brightest star in the night sky. Like most open clusters, it is relatively young – 190 million years old – and contains over 100 stars in a region measuring 25 to 26 light years in diameter.
Description:
Running away from us at a speed of about 34 kilometers per second, this field of about 100 stars measures about 25 light years across. Born about 240 million years ago, it resides in space approximately 2300 light years away from our solar system. Larger aperture telescopes will reveal the presence of many red (or orange) giant stars and the hottest star in this group is a spectral type A.
View of the night sky in North Carolina, showing the constellations of Orion, Hyades, Canis Major and Canis Minor. Credit: NASA
As G.L.H. Harris (et al) explained in a 1993 study:
“We have obtained photoelectric UBV photometry for 100 stars, uvbyb photometry for 39 stars and MK spectral types for 80 stars in the field of NGC 2287. After combination with data from other sources, several interesting cluster properties are apparent. Both the UBV and uvbyb photometry point to a small but nonzero reddening, while our spectral types confirm previous results indicating a high binary frequency for the cluster. Based on our spectral and photometric data for the cluster members, we find a minimum binary frequency of 40% and discuss the possibility that the results may imply a binary frequency closer to 80%. The cluster age is found to be based on both the main-sequence turnoff and the red giant distribution; the width of the turn up region can probably be explained by a combination of duplicity and a range in stellar rotation.”
But there’s more than just red giant stars and various spectral types to be found hiding in Messier 41. There’s at least two white dwarf stars, too. As P.D Dobbie explained in a 2009 study:
“[W]e use our estimates of their cooling times together with the cluster ages to constrain the lifetimes and masses of their progenitor stars. We examine the location of these objects in initial mass-final mass space and find that they now provide no evidence for substantial scatter in initial mass-final mass relation (IFMR) as suggested by previous investigations. This form is generally consistent with the predictions of stellar evolutionary models and can aid population synthesis models in reproducing the relatively sharp drop observed at the high mass end of the main peak in the mass distribution of white dwarfs.”
Messier 41 and Collinder 121. Image: Wikisky
As you view Messier 41, you’ll be impressed with its wide open appearance… and knowing it’s simply what happens to star clusters as they get passed around our galaxy. As Giles Bergond (et al.) stated in their 2001 study:
“Taking into account observational biases, namely the galaxy clustering and differential extinction in the Galaxy, we have associated these stellar overdensities with real open cluster structures stretched by the galactic gravitational field. As predicted by theory and simulations, and despite observational limitations, we detected a general elongated (prolate) shape in a direction parallel to the galactic Plane, combined with tidal tails extended perpendicularly to it. This geometry is due both to the static galactic tidal field and the heating up of the stellar system when crossing the Disk. The time varying tidal field will deeply affect the cluster dynamical evolution, and we emphasize the importance of adiabatic heating during the Disk-shocking. During the 10-20 Z-oscillations experienced by a cluster before its dissolution in the Galaxy, crossings through the galactic Disk contribute to at least 15% of the total mass loss. Using recent age estimations published for open clusters, we find a destruction time-scale of about 600 million years for clusters in the solar neighborhood.”
That means we’ve only got another 360 million years to observe it before it’s completely gone (though some estimates place it at about 500 million). Either way, this star cluster is destined to disappear, perhaps before we are!
History of Observation:
Messier 41 was “possibly” recorded by Aristotle about 325 B.C. as a patch in the Milky Way… quite understandable since it is very much within unaided eye visibility from a dark sky location. Said Aristotle:
“.. some of the fixed stars have tails. And for this we need not rely only on the evidence of the Egyptians who say they have observed it; we have observed it also ourselves. For one of the stars in the thigh of the Dog had a tail, though a dim one: if you looked hard at it the light used to become dim, but to less intent glance it was brighter.”
Messier 41 and Sirius. Image: Wikisky
However, Giovanni Batista Hodierna was the first to catalog it in 1654, and the star cluster became a bit more astronomically known when John Flamsteed independently found it again on February 16, 1702. Doing his duty, Charles Messier also logged it:
“In the night of January 16 to 17, 1765, I have observed below Sirius and near the star Rho of Canis Major a star cluster; when examining it with a night refractor, this cluster appeared nebulous; instead, there is nothing but a cluster of small stars. I have compared the middle with the nearest known star; and I found its right ascension of 98d 58′ 12″, and its declination 20d 33′ 50″ north.”
Following suit, other historical astronomers also observed M41 – including Sir John Herschel to include it in the NGC catalog. While none found it particularly thrilling… their notes range from a “coarse collection of stars” to “very large, bright, little compressed”, perhaps you will feel much differently about this easy, bright target!
Locating Messier 41:
Finding Messier 41 isn’t very difficult for binoculars and small telescopes – all you have to know is the brightest star in the northern hemisphere, Sirius, and south! Simply aim your optics at Sirius and move due south approximately four degrees. That’s about one standard field of view for binoculars, about one field of view for the average telescope finderscope and about 6 fields of view for the average wide field, low power eyepiece.
The location of Messier 41 in the Canis Major constellation. Credit: IAU and Sky & Telescope magazine/Roger Sinnott & Rick Fienberg
Because Messier 41 is a large star cluster, remember to use lowest magnification to get the best effect. Higher magnification can always be used once the star cluster is identified to study individual members. M41 is quite bright and easily resolved and makes a wonderful target for urban skies and moonlit nights!
Because you understand what’s there…
Object Name: Messier 41 Alternative Designations: M41, NGC 2287 Object Type: Open Galactic Star Cluster Constellation: Canis Major Right Ascension: 06 : 46.0 (h:m) Declination: -20 : 44 (deg:m) Distance: 2.3 (kly) Visual Brightness: 4.5 (mag) Apparent Dimension: 38.0 (arc min)
The U.S. Air Force's X-37B Orbital Test Vehicle 4 is seen after at NASA 's Kennedy Space Center Shuttle Landing Facility in Florida May 7, 2017. Credit: US Department of Defense, courtesy of United Launch Alliance.
The Air Force’s secretive X-37B space plane landed at the Kennedy Space Center’s orbiter runway on Sunday, May 7, after spending a record 718 days in orbit. This was the fourth flight of the uncrewed, autonomous military project, and was the first landing for an X-37B at KSC.
“The landing of OTV-4 marks another success for the X-37B program and the nation,” said Lt. Col. Ron Fehlen, X-37B program manager. “This mission once again set an on-orbit endurance record and marks the vehicle’s first landing in the state of Florida. We are incredibly pleased with the performance of the space vehicle and are excited about the data gathered to support the scientific and space communities. We are extremely proud of the dedication and hard work by the entire team.”
The mini space shuttle launched on May 20, 2015 on its somewhat clandestine mission. The launch was well publicized (and shown live on a webcast) but the landing came unannounced, except for the sonic boom that heralded its arrival, surprising those living around the space coast area.
The Air Force revealed before the launch that it would carry an experimental electric propulsion thruster to be tested in orbit and an investigation called Materials Exposure and Technology Innovation in Space (METIS), which exposes sample materials to the space environment and builds on more than ten years of similar research on the International Space Station.
Beyond that, however, what the X-37B did in orbit is not known. The Air Force said in a news release is that mini shuttle is “an experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform for the U.S. Air Force.” Some experts has said they believe it has intelligence-gathering equipment.
Technicians work on the Air Force X-37B Orbital Test Vehicle 4, which landed at NASA’s Kennedy Space Center Shuttle Landing Facility in Florida May 7, 2017. Credit: Secretary of the Air Force Public Affairs.
Satellite-tracking enthusiasts were able to monitor the ship’s changing orbital height at various times throughout the mission.
The reusable space plane is designed to be launched like a satellite and land on a runway like an airplane and the NASA space shuttles. The 11,000 pound (4990 kg) OTV space plane was built by Boeing and is about a quarter the size of a NASA space shuttle. It was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.
Note: In the above video you’ll see a “big” NASA space shuttle sitting near the runway. It is the mockup of a space shuttle that used to be at the entrance of the Kennedy Space Center visitor complex. It is currently being restored.
All four OTV missions launched from Cape Canaveral, Florida and previous missions landed at Vandenberg Air Force Base, California. The first OTV mission launched on April 22, 2010, and concluded on Dec. 3, 2010, after 224 days in orbit. The second OTV spent 468 days on orbit, and the third mission was 674 days long.
The Air Force said they are preparing to launch the fifth X-37B mission from Cape Canaveral Air Force Station, Florida, later in 2017.
Damian Peach reprocessed one of the latest images taken by Juno's JunoCam during its 3rd close flyby of the planet on Dec. 11. The photo highlights two large 'pearls' or storms in Jupiter's atmosphere. Credit: NASA/JPL-Caltech/SwRI/MSSS
The gas giants have always been a mystery to us. Due to their dense and swirling clouds, it is impossible to get a good look inside them and determine their true structure. Given their distance from Earth, it is time-consuming and expensive to send spacecraft to them, making survey missions few and far between. And due to their intense radiation and strong gravity, any mission that attempts to study them has to do so carefully.
And yet, scientists have been of the opinion for decades that this massive gas giant has a solid core. This is consistent with our current theories of how the Solar System and its planets formed and migrated to their current positions. Whereas the outer layers of Jupiter are composed primarily of hydrogen and helium, increases in pressure and density suggest that closer to the core, things become solid.
Structure and Composition:
Jupiter is composed primarily of gaseous and liquid matter, with denser matter beneath. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules, and approx. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements.
Jupiter’s structure and composition. Credit: Kelvinsong CC by S.A. 3.0
The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds, as well as trace amounts of benzene and other hydrocarbons. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. Crystals of frozen ammonia have also been observed in the outermost layer of the atmosphere.
The interior contains denser materials, such that the distribution is roughly 71% hydrogen, 24% helium and 5% other elements by mass. It is believed that Jupiter’s core is a dense mix of elements – a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen. The core has also been described as rocky, but this remains unknown as well.
In 1997, the existence of the core was suggested by gravitational measurements, indicating a mass of 12 to 45 times the mass of Earth, or roughly 4%–14% of the total mass of Jupiter. The presence of a core is also supported by models of planetary formation that indicate how a rocky or icy core would have been necessary at some point in the planet’s history. Otherwise, it would not have been able to collect all of its hydrogen and helium from the protosolar nebula – at least in theory.
However, it is possible that this core has since shrunk due to convection currents of hot, liquid, metallic hydrogen mixing with the molten core. This core may even be absent now, but a detailed analysis is needed before this can be confirmed. The Juno mission, which launched in August 2011 (see below), is expected to provide some insight into these questions, and thereby make progress on the problem of the core.
Formation and Migration:
Our current theories regarding the formation of the Solar System claim that the planets formed about 4.5 billion years ago from a Solar Nebula (i.e. Nebular Hypothesis). Consistent with this theory, Jupiter is believed to have formed as a result of gravity pulling swirling clouds of gas and dust together.
Jupiter acquired most of its mass from material left over from the formation of the Sun, and ended up with more than twice the combined mass of the other planets. In fact, it has been conjectured that it Jupiter had accumulated more mass, it would have become a second star. This is based on the fact that its composition is similar to that of the Sun – being made predominantly of hydrogen.
Artist’s concept of a young star surrounded by a disk of gas and dust – called a protoplanetary disk. Credit: NASA/JPL-Caltech
In addition, current models of Solar System formation also indicate that Jupiter formed farther out from its current position. In what is known as the Grand Tack Hypothesis, Jupiter migrated towards the Sun and settled into its current position by roughly 4 billion years ago. This migration, it has been argued, could have resulted in the destruction of the earlier planets in our Solar System – which may have included Super-Earths closer to the Sun.
Exploration:
While it was not the first robotic spacecraft to visit Jupiter, or the first to study it from orbit (this was done by the Galileo probe between 1995 and 2003), the Juno mission was designed to investigate the deeper mysteries of the Jovian giant. These include Jupiter’s interior, atmosphere, magnetosphere, gravitational field, and the history of the planet’s formation.
The mission launched in August 2011 and achieved orbit around Jupiter on July 4th, 2016. The probe entered its polar elliptical orbit after completing a 35-minute-long firing of the main engine, known as Jupiter Orbital Insertion (or JOI). As the probe approached Jupiter from above its north pole, it was afforded a view of the Jovian system, which it took a final picture of before commencing JOI.
Since that time, the Juno spacecraft has been conducting perijove maneuvers – where it passes between the northern polar region and the southern polar region – with a period of about 53 days. It has completed 5 perijoves since it arrived in June of 2016, and it is scheduled to conduct a total of 12 before February of 2018. At this point, barring any mission extensions, the probe will de-orbit and burn up in Jupiter’s outer atmosphere.
As it makes its remaining passes, Juno will gather more information on Jupiter’s gravity, magnetic fields, atmosphere, and composition. It is hoped that this information will teach us much about how the interaction between Jupiter’s interior, its atmosphere and its magnetosphere drives the planet’s evolution. And of course, it is hoped to provide conclusive data on the interior structure of the planet.
Does Jupiter have a solid core? The short answer is, we don’t know… yet. In truth, it could very well have a solid core composed of iron and quartz, which is surrounded by a thick layer of metallic hydrogen. It is also possible that interaction between this metallic hydrogen and the solid core caused the the planet to lose it some time ago.
At this point, all we can do is hope that ongoing surveys and missions will yield more evidence. These are not only likely to help us refine our understanding of Jupiter’s internal structure and its formation, but also refine our understanding of the history of the Solar System and how it came to be.
Artist's impression of the Epsilon Eridani system, showing Epsilon Eridani b (a Jupiter-mass planet) and a series of asteroid belts and comets. Credit: NASA/SOFIA/Lynette Cook.
Astronomers are understandanly fascinated with the Epsilon Eridani system. For one, this star system is in close proximity to our own, at a distance of about 10.5 light years from the Solar System. Second, it has been known for some time that it contains two asteroid belts and a large debris disk. And third, astronomers have suspected for many years that this star may also have a system of planets.
On top of all that, a new study by a team of astronomers has indicated that Epsilon Eridani may be what our own Solar System was like during its younger days. Relying on NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft, the team conducted a detailed analysis of the system that showed how it has an architecture remarkably similar to what astronomer believe the Solar System once looked like.
Led by Kate Su – an Associate Astronomer with the Steward Observatory at the University of Arizona – the team includes researchers and astronomers from the Department of Physics & Astronomy of Iowa State University, the Astrophysical Institute and University Observatory at the University of Jena (Germany), and NASA’s Jet Propulsion Laboratory and Ames Research Center.
Artist’s diagram showing the similar structure of the Epsilon Eridani to the Solar System. Credit: NASA/JPL-Caltech
For the sake of their study – the results of which were published in The Astronomical Journal under the title “The Inner 25 AU Debris Distribution in the Epsilon Eri System” – the team relied on data obtained by a flight of SOFIA in January 2015. Combined with detailed computer modeling and research that went on for years, they were able to make new determinations about the structure of the debris disk.
As already noted, previous studies of Epsilon Eridani indicated that the system is surrounded by rings made up of materials that are basically leftovers from the process of planetary formation. Such rings consist of gas and dust, and are believed to contain many small rocky and icy bodies as well – like the Solar System’s own Kuiper Belt, which orbits our Sun beyond Neptune.
Careful measurements of the disk’s motion has also indicated that a planet with nearly the same mass as Jupiter circles the star at a distance comparable to Jupiter’s distance from the Sun. However, based on prior data obtained by the NASA’s Spitzer Space Telescope, scientists were unable to determine the position of warm material within the disk – i.e. the dust and gas – which gave rise to two models.
In one, warm material is concentrated into two narrow rings of debris that orbit the star at distances corresponding respectively to the Main Asteroid Belt and Uranus in our Solar System. According to this model, the largest planet in the system would likely be associated with an adjacent debris belt. In the other, warm material is in a broad disk, is not concentrated into asteroid belt-like rings, and is not associated with any planets in the inner region.
NASA’s SOFIA aircraft before a 2015 flight to observe a nearby star. Credit: Massimo Marengo.
Using the new SOFIA images, Su and her team were able to determine that the warm material around Epsilon Eridani is arranged like the first model suggests. In essence, it is in at least one narrow belt, rather than in a broad continuous disk. As Su explained in a NASA press release:
“The high spatial resolution of SOFIA combined with the unique wavelength coverage and impressive dynamic range of the FORCAST camera allowed us to resolve the warm emission around eps Eri, confirming the model that located the warm material near the Jovian planet’s orbit. Furthermore, a planetary mass object is needed to stop the sheet of dust from the outer zone, similar to Neptune’s role in our solar system. It really is impressive how eps Eri, a much younger version of our solar system, is put together like ours.”
These observations were made possible thanks to SOFIA’s on-board telescopes, which have a greater diameter than Spitzer – 2.5 meters (100 inches) compared to Spitzer’s 0.85 m (33.5 inches). This allowed for far greater resolution, which the team used to discern details within the Epsilon Eridani system that were three times smaller than what had been observed using the Spitzer data.
In addition, the team made use of SOFIA’s powerful mid-infrared camera – the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST). This instrument allowed the team to study the strongest infrared emissions coming from the warm material around the star which are otherwise undetectable by ground-based observatories – at wavelengths between 25-40 microns.
This artist’s conception of the Epsilon Eridani system, the closest star system who’s structure resembles a young Solar System. Credit: NASA/JPL/Caltech
These observations further indicate that the Epsilon Eridani system is much like our own, albeit in younger form. In addition to having asteroid belts and a debris disk that is similar to our Main Belt and Kuiper Belt, it appears that it likely has more planets waiting to be found within the spaces between. As such, the study of this system could help astronomers to learn things about the history of our own Solar System.
Massimo Marengo, one of he co-authors of the study, is an Associate Professor with the Department of Physics & Astronomy at Iowa State University. As he explained in a University of Iowa press release:
“This star hosts a planetary system currently undergoing the same cataclysmic processes that happened to the solar system in its youth, at the time in which the moon gained most of its craters, Earth acquired the water in its oceans, and the conditions favorable for life on our planet were set.”
At the moment, more studies will need to be conducted on this neighboring stars system in order to learn more about its structure and confirm the existence of more planets. And it is expected that the deployment of next-generation instruments – like the James Webb Space Telescope, scheduled for launch in October of 2018 – will be extremely helpful in that regard.
“The prize at the end of this road is to understand the true structure of Epsilon Eridani’s out-of-this-world disk, and its interactions with the cohort of planets likely inhabiting its system,” Marengo wrote in a newsletter about the project. “SOFIA, by its unique ability of capturing infrared light in the dry stratospheric sky, is the closest we have to a time machine, revealing a glimpse of Earth’s ancient past by observing the present of a nearby young sun.”
SpaceX Falcon 9 rocket carrying classified NROL-76 surveillance satellite for the National Reconnaissance Office successfully launches shortly after sunrise from Launch Complex 39A on 1 May 2017 from NASA’s Kennedy Space Center in Florida. 1st stage accomplished successful ground landing at the Cape nine minutes later. Credit: Ken Kremer/Kenkremer.com
SpaceX Falcon 9 rocket carrying classified NROL-76 surveillance satellite for the National Reconnaissance Office successfully launches shortly after sunrise from Launch Complex 39A on 1 May 2017 from NASA’s Kennedy Space Center in Florida. 1st stage accomplished successful ground landing at the Cape nine minutes later. Credit: Ken Kremer/Kenkremer.com
Blastoff of SpaceX Falcon 9 delivering NROL-76 spy satellite to orbit on 1 May 2017 for the U.S. National Reconnaissance Office. Credit: Julian Leek
The stunning events were captured by journalists and tourists gathered from around the globe to witness history in the making with their own eyeballs.
Check out this expanding gallery of eyepopping photos and videos from several space journalist colleagues and friends and myself – for views you won’t see elsewhere.
Click back as the gallery grows !
Landing legs unfurl and lock in place mere seconds before soft landing via propulsive firing of SpaceX Falcon 9 first stage booster engines at Landing Zone 1 on Canaveral Air Force Station only 9 minutes after launch from pad 39A on 1 May 2017 from NASA’s Kennedy Space Center in Florida as seen from Exploration Tower at Port Canaveral, FL. Credit: Dawn Leek
The milestone SpaceX mission to launch the first satellite in support of US national defense was apparently a complete success.
SpaceX Falcon 9 rocket carrying classified NROL-76 surveillance satellite for the National Reconnaissance Office successfully launches shortly after sunrise from Launch Complex 39A on 1 May 2017 from NASA’s Kennedy Space Center in Florida. 1st stage accomplished successful ground landing at the Cape nine minutes later. Credit: Ken Kremer/Kenkremer.comUp close view of engine exhaust flames whipping around SpaceX Falcon 9 first stage booster during propulsive descent Merlin 1 D engines fire with 4 grid fins deployed after successful NROL-76 spysat launch for the NRO on 1 May 2017 from NASA’s Kennedy Space Center in Florida. 1st stage descent culminated seconds later in successful ground landing at the Cape’s LZ-1 nine minutes later. Credit: Ken Kremer/Kenkremer.comFlames whip around booster darting in and out of clouds during propulsive descent of the SpaceX Falcon 9 first stage firing Merlin 1 D engines with 4 grid fins deployed after successful NROL-76 spysat launch for the NRO on 1 May 2017 from NASA’s Kennedy Space Center in Florida. 1st stage descent culminated seconds later in successful ground landing at the Cape’s LZ-1 nine minutes later. Credit: Ken Kremer/Kenkremer.com
Check out these exquisite videos from a wide variety of vantage points including remote cameras at the pad, Cape Canaveral media viewing site and public viewing locations off base.
Video Caption: SpaceX Falcon 9 liftoff with NROL-76 on 1 May 2017. This is the first launch of an NRO satellite on a SpaceX Falcon 9 rocket and the 4th launch from Pad 39A this year. Credit: Jeff Seibert
In this cool video you can distinctly hear the Falcon 9 sonic booms eminating at LZ-1 from pad 39A sending birds fleeing aflutter in fright!
Video Caption: Falcon 9 sonic booms heard from Pad 39A. These two cameras recorded the launch of the NROL-76 satellite at https://youtu.be/kkKTe_61jk0
Nine minutes after launch, they recorded the sonic booms caused by the booster landing at LZ-1, 9.5 miles south of Launch Pad 39A on 1 May 2017. Credit: Jeff Seibert
Video Caption: SpaceX Launch and Best Landing – NROL76 05-01-2017. Best landing for spectators. Watch the nitrogen thruster’s steer the 16 story booster. Hear double sonic boom at the end. Audio is delayed from podcast. We can not match SpaceX and NASA tracking telescope coverage. Was really awesome for all who witnessed. Credit: USLaunchReport
NROL-76 marks the fifth SpaceX launch of 2017 and the fourth from pad 39A.
The NRO is a joint Department of Defense–Intelligence Community organization responsible for developing, launching, and operating America’s intelligence satellites to meet the national security needs of our nation, according to the NRO.
SpaceX Falcon 9 begins to deploy quartet of landing legs spreading out from the top down mere 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 1 May 2017 from NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/Kenkremer.com SpaceX Falcon 9 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 1 May 2017 from NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/Kenkremer.comSpaceX Falcon 9 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 1 May 2017 from NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/Kenkremer.com
Watch for Ken’s continuing coverage direct from onsite at the Kennedy Space Center press site and Cape Canaveral Air Force Station.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
SpaceX Falcon 9 rocket carrying classified NROL-76 surveillance satellite for the National Reconnaissance Office successfully launches shortly after sunrise from Launch Complex 39A on 1 May 2017 from NASA’s Kennedy Space Center in Florida. 1st stage accomplished successful ground landing at the Cape nine minutes later. Credit: Ken Kremer/Kenkremer.com Blastoff of SpaceX Falcon 9 delivering NROL-76 spy satellite to orbit on 1 May 2017 for the U.S. National Reconnaissance Office. Credit: Julian LeekSpaceX Falcon 9 rocket carrying classified NROL-76 surveillance satellite for the National Reconnaissance Office stands raised erect poised for sunrise liftoff from Launch Complex 39A on 30 April 2017 from NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/Kenkremer.com
Looking to the future of space exploration, NASA and TopCoder have launched the "High Performance Fast Computing Challenge" to improve the performance of their Pleiades supercomputer. Credit: NASA/MSFC
For decades, NASA’s Aeronautics Research Mission Directorate (ARMD) has been responsible for developing the technologies that put satellites into orbit, astronauts on the Moon, and sent robotic missions to other planets. Unfortunately, after many years of supporting NASA missions, some of their machinery is getting on in years and is in need of an upgrade.
Consider the Pleiades supercomputer, the distributed-memory machine that is responsible for conducting modeling and simulations for NASA missions. Despite being one of the fastest supercomputers in the world, Pleiades will need to be upgraded in order to stay up to task in the years ahead. Hence why NASA has come together with TopCoder (and with the support of HeroX) to launch the High Performance Fast Computing Challenge (HPFCC).
With a prize purse of $55,000, NASA and TopCoder are seeking programmers and computer specialists to help them upgrade Pleiades so it can perform computations faster. Specifically, they want to improve its FUN3D software so that flow analysis which previously took months can now be done in days or hours. In short, they want to speed up their supercomputers by a factor of 10 to 1000 while relying on its existing hardware, and without any decreases in accuracy.
The addition of Haswell processors in 2015 increased the theoretical peak processing capability of Pleiades from 4.5 petaflops to 5.3 petaflops. Credit: NASA
Those hoping to enter need to be familiar with FUN3D software, which is used to calculate the nonlinear partial differential equations (aka. Navier-Stokes equations) that are used for steady and unsteady flow computations. These include large eddy simulations in computational fluid dynamics (CFD), which are of particular importance when it comes to supersonic aircraft, space flight, and the development launch vehicles and planetary reentry systems.
NASA has partnered to launch this challenge with TopCoder, the world’s largest online community of designers, developers and data scientists. Since it was founded in 2001, this company has hosted countless online competitions (known as “single round matches”, or SRMs) designed to foster better programming. They also host weekly competitions to stimulate developments in graphic design.
Overall, the HPFSCC will consist of two challenges – the Ideation Challenge and the Architecture Challenge. For the Ideation Challenge (hosted by NASA), competitors must propose ideas that can help optimize the Pleiades source code. As they state, may include (but is not limited to) “exploiting algorithmic developments in such areas as grid adaptation, higher-order methods and efficient solution techniques for high performance computing hardware.”
The computation of fluid dynamics is of particular importance when plotting space launches and reentry. Credit: NASA/JPL-Caltech
The Architecture Challenge (hosted by TopCoder), is focused less on strategy and more on measurable improvements. As such, participants will be tasked with showing how to optimize processing in order to reduce the overall time and increase the efficiency of computing models. Ideally, says TopCoder, this would include “algorithm optimization of the existing code base, inter-node dispatch optimization, or a combination of the two.”
NASA is providing $20,000 in prizes for the Ideation challenge, with $10,000 awarded for first place, and two runner-up awards of $5000 each. TopCoder, meanwhile, is offering $35,000 for the Architecture challenge – a top prize of $15,000 for first place, $10,000 for second place, with $10,000 set aside for the Qualified Improvement Candidate Prize Pool.
The competition will remain open to submissions until June 29th, 2017, at which point, the judging will commence. This will wrap up on August 7th, and the winners of both competitions will be announced on August 9th. So if you are a coder, computer engineer, or someone familiar with FUN3D software, be sure to head on over to HeroX and accept the challenge!
Human space exploration continues to advance, with missions planned for the Moon, Mars, and beyond. With an ever-expanding presence in space and new challenges awaiting us, it is necessary that we have the right tools to make it all happen. By leveraging improvements in computer programming, we can ensure that one of the most important aspects of mission planning remains up to task!
