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A manned mission to Mars is a hot topic in space, and has been for a long time. Most of the talk around it has centred on the required technology, astronaut durability, and the overall feasibility of the mission. But now, some of the talk is focussing on the legal framework behind such a mission.
In April 2016, SpaceX announced their plans for a 2018 mission to Mars. Though astronauts will not be part of the mission, several key technologies will be demonstrated. SpaceX's Dragon capsule will make the trip to Mars, and will conduct a powered, soft landing on the surface of the red planet. The capsule itself will be launched by another new piece of technology, SpaceX's Falcon Heavy rocket.
It's a fascinating development in space exploration; a private space company, in cooperation with NASA, making the trip to Mars with all of its own in-house technology. But above and beyond all of the technological challenges, there is the challenge of making the whole endeavour legal.
Though it's not widely known or talked about, there are legal implications to launching things into space. In the US, each and every launch by a private company has to have clearance from the Federal Aviation Administration (FAA).
That's because the US signed the Outer Space Treaty in 1969, a treaty that sets out the obligations and limitations to activities in space. The FAA has routinely given their ascent to commercial launches, but things may be starting to get a little tricky in space.
The most recent Humans To Mars Summit, a conference focussed on Mars missions and explorations, just wrapped up on May 19th. At that conference, George Nield, associate administrator for commercial space transportation at the FAA, addressed the issue. “That’ll be an FAA licensed launch as well,” said Nield of the SpaceX mission to Mars. “We’re already working with SpaceX on that mission," he added. "There are some interesting policy questions that have to do with the Outer Space Treaty,” said Nield.
The Outer Space Treaty was signed in 1967, and has some sway over space exploration and colonization. Though it gives wide latitude to governments that are exploring space, how it will affect commercial activity like resource exploitation, and installations like settlements in other planets, is not so clear.
According to Nield, the FAA is interested in Article VI of the treaty and how it might impact SpaceX's planned mission to Mars. Article VI states that all signees to the treaty “shall bear international responsibility for national activities in outer space, including the Moon and other celestial bodies, whether such activities are carried on by governmental agencies or by non-governmental entities.”
Article VI also says, "the activities of non-governmental entities in outer space, including the Moon and other celestial bodies, shall require authorization and continuing supervision by the appropriate State Party to the Treaty."
What this language means is that the US government itself will bear responsibility for the SpaceX Mars mission. Obviously, this kind of treaty obligation is important. There isn't exactly a huge list of private companies exploring space, but that will change as the years pass. It seems likely that the bulk of commercial space exploration and resource utilization will be centred in the US, so how the US deals with their treaty obligations will be of immense interest now and in the future.
The treaty itself is mostly focused on avoiding military activity in space. It prohibits things like weapons of mass destruction in space, and weapons testing or military bases on the Moon or other celestial bodies. The treaty also states that the Moon and other planets and bodies cannot be claimed by any nation, and that these and other bodies "are the common heritage of mankind." Good to know.
Taken as a whole, it's easy to see why the Treaty is important. Space can't become a free-for-all like Earth has been in the past. There has to be some kind of framework. “A government needs to oversee these non-governmental activities,” according to Nield.
There's another aspect to all of this. Governments routinely sign treaties, and then try to figure out ways around them, while hoping their rivals won't do the same. It's a sneaky, tactical business, because governments can't grossly ignore treaties, else the other co-signatories abandon said treaty completely. A case in point is last year's law, signed by the US Congress, which makes it legal for companies to mine asteroids. This law could be interpreted as violating the Treaty.
Governments can claim, for instance, that their activities are scientific rather than military. Geo-political influence depends greatly on projecting power. If one nation can project power into space, while claiming their activities are scientific rather than military, they will gain an edge over their rivals. Countries also seek to bend the rules of a treaty to satisfy their own interests, while preventing other countries from doing the same. Just look at history.
We're not in that type of territory yet. So far, no nation has had an opportunity to really violate the treaty, though the asteroid mining law passed by the US Congress comes close.
The SpaceX mission to Mars is a very important one, in terms of how the Outer Space Treaty will be tested and adhered to. More and more countries, and private companies, are becoming space-farers. The legality of increasingly complex missions in space, and the eventual human presence on the Moon and Mars, is a fascinating one not usually addressed by the space science community.
We in the space science community are primarily interested in technological advances, and in the frontiers of human knowledge. It might be time for us to start paying attention to the legal side of things. Space exploration could turn out to have an element of courtroom drama to it.
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Explanation: Influenced by the strong Pacific El Nino, cloudy skies have more often come to Chile's high Atacama Desert this season, despite its reputation as an astronomer's paradise. Located in one of the driest, darkest places on planet Earth, domes of the region's twin 6.5 meter Magellan telescopes of Carnegie Las Campanas Observatory were closed on May 13. Still, a first quarter Moon and bright stars shine through in this panoramic night skyscape, the lunar disk surrounded by a beautiful, bright halo. The angular radius of the halo is 22 degrees. Not determined by the brightness or phase of the Moon itself, the angle is set by the hexagonal geometry of atmospheric ice crystals that reflect and refract the moonlight. On that night, the brilliant star just inside the halo's radius was really planet Jupiter. The brightest star flanking the halo to the far left is Canopus, with Arcturus on the halo's right.
It came from outer space—literally! On Tuesday, May 17, 2016, the early morning sky briefly lit up with the brilliant flash of a fireball—that is, an extremely bright meteor—over much of eastern New England states and even parts of southeastern Canada.
The event, which occurred around 12:50 a.m. EDT (04:50 UTC), was reported by witnesses from Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, Ontario, and Québec, and captured on several automated cameras like a webcam in Portsmouth, NH (seen above) and a police dashcam in Plattsburgh, NY (below).
The fireball appeared to be moving from southwest to northeast and for some witnesses created an audible sonic boom, heard (and felt) several minutes later.
Meteors are the result of debris in space rapidly entering Earth's upper atmosphere, compressing the air and causing it to quickly release energy in the form of heat and optical light. If the entering object is massive enough it may violently disintegrate during its fall, creating both light and sound. This particular meteor technically classifies as a bolide, due to its brightness, eruption, and visible fragmentation. Learn more about the various types of meteors here.
No reports of a meteorite impact at ground level have been made although I must assume there will be individuals who go on the hunt—meteorite fragments, especially those associated with witnessed events, can be quite valuable.
Did you witness the event or capture it on camera? Report your sighting of this or any other fireballs on the AMS siteand be sure to send your fireball videos or images to the American Meteor Society here.
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Welcome back to Messier Monday! Today, in our ongoing tribute to Tammy Plotner, we take a look at the M14 globular cluster!
In the 18th century, French astronomer Charles Messier began cataloging all the “nebulous objects” he had come to find while searching the night sky. Having originally mistook these for comets, he compiled a list these objects in the hopes of preventing future astronomers from making the same mistake. In time, the list would include 100 objects, and would come to be known as the Messier Catalog to posterity.
One of these objects was the globular cluster which he would designate as M14. Located in the southern constellation Ophiuchus, this slightly elliptically-shaped stellar swarm contains several hundred thousand stars, a surprising number of which are variables. Despite these stars not being densely concentrated in the central region, this object is not hard to spot for amateur astronomers that are dedicated to their craft!
Description:
Located some 30,000 light years from Earth and measuring 100 light years in diameter, this globular cluster can be found in the southern Ophiuchus constellation, along with several other Messier Objects. Although it began its life some 13.5 billion years ago, it is far from being done changing. It is still shaking intracluster dust from its shoes.
What this means is that M14, like many globular clusters, contains a good deal of matter that it picked up during its many times orbiting the center of our Galaxy. According to studies done by N. Matsunaga (et al):
"Our goal is to search for emission from the cold dust within clusters. We detect diffuse emissions toward NGC 6402 and 2808, but the IRAS 100-micron maps show the presence of strong background radiation. They are likely emitted from the galactic cirrus, while we cannot rule out the possible association of a bump of emission with the cluster in the case of NGC 6402. Such short lifetime indicates some mechanism(s) are at work to remove the intracluster dust... (and) its impact on the chemical evolution of globular clusters."
Another thing that makes Messier 14 unusual is the presence of CH stars, such as the one that was discovered in 1997. CH stars are a very specific type of Population II carbon stars that can be identified by CH absorption bands in the spectra. Middle aged and metal poor, these underluminous suns are known to be binaries. Patrick Cote, the chief author of the research team that discovered the star, wrote in their research report to the American Astronomical Society:
"We report the discovery of a probable CH star in the core of the Galactic globular cluster M14 (=NGC 6402 = C1735-032), identified from an integrated-light spectrum of the cluster obtained with the MOS spectrograph on the Canada-France-Hawaii telescope. Both the star's location near the tip of the red giant branch in the cluster color-magnitude diagram and its radial velocity therefore argue for membership in M14. Since the intermediate-resolution MOS spectrum shows not only enhanced CH absorption but also strong Swan bands of C2, M14 joins Centaurus as the only globular clusters known to contain "classical" CH stars. Although evidence for its duplicity must await additional radial velocity measurements, the CH star in M14 is probably, like all field CH stars, a spectroscopic binary with a degenerate (white dwarf) secondary."
Messier 14 was also the site of a nova that appeared in 1938. However, it was not registered until 1964, when Amelia Wehlau of the University of Western Ontario surveyed a collection of photographic plates taken by Helen Sawyer Hogg between 1932 and 1963. NASA's Hubble Space Telescope (HST) took a look for the nova' remnants, too, planning for more than a decade to obtain images and spectra of this region.
The Hubble team, which was led by Bruce Margon of the University of Washington, used the European Space Agency's Faint Object Camera (FOC) onboard HST to observe space in the vicinity of the nova. As the indicated in the research paper - titled "Faint Camera Observations Of A Globular Cluster Nova Field":
"The results are tremendously encouraging not only with respect to locating the quiescent nova, but also as a preview of the use of HST cameras in crowded, faint regions such as globular clusters. It is already clear even from this preliminary stage of the analysis that we have learned much. The brightness today of the nova remnant must be considerably less than suggested by the ground-based data, which we now know to have summed at least five separate stars."
History of Observation:
M14 is one of the original discoveries of Charles Messier, who cataloged it on June 1st, 1764. In his notes, he wrote of the object:
"In the same night of June 1 to 2, 1764, I have discovered a new nebula in the garb which dresses the right arm of Ophiuchus; on the charts of Flamsteed it is situated on the parallel of the star Zeta Serpentis: that nebula is not considerable, its light is faint, yet it is seen well with an ordinary [non-achromatic] refractor of 3 feet and a half [FL]; it is round, and its diameter can be 2 minutes of arc; above it and very close to it is a small star of the nineth magnitude. I have employed for seeing this nebula nothing but the ordinary refractor of 3 feet & a half with which I have not noticed any star; maybe with a larger instrumentone could perceive one. I have determined the position of that nebula by its passage of the Meridian, comparing it with Gamma Ophiuchi, it has resulted for its right ascension 261d 18' 29", and for its declination 3d 5' 45" south. I have marked that nebula on the chart of the apparent path of the Comet which I have observed last year [the comet of 1769]."
But as usual, it was Admiral Smyth who historically recorded it best when he said:
"A large globular cluster of compressed minute stars, on the Serpent-bearer's left arm. This fine object is of a lucid white colour, and very nebulous in aspect; which may be partly owing to its being situated in a splendid field of stars, the lustre of which interferes with it. By diminishing the field under high powers, some of the brightest of these attendants are excluded, but the cluster loses its definition. It was discovered by Messier in 1764, and thus described: "A small nebula, no star; light faint; form round; and may be seen with a telescope 3 1/2 feet long." The mean apparent place is obtained by differentiation from Gamma Ophiuchi, from which it is south-by-west about 6deg 1/2, being nearly midway between Beta Scorpii and the tail of Aquila, and 16deg due south of Rasalague [Alpha Ophiuchi]. Sir William Herschel resolved this object in 1783, with his 20-foot reflector, and he thus entered it: "Extremely bright, round, easily resolvable; with [magnification] 300 I can see the stars. The heavens are pretty rich in stars of a certain size [magnitude, brightness], but they are larger [brighter] than those in the cluster, and easily to be distinguished from them. This cluster is considerably behind the scattered stars, as some of them are projected upon it." He afterwards added: "From the observations with the 20-foot telescope, which in 1791 and 1799 had the power of discering stars 75-80 times as far as the eye, the profundity of this cluster must be of the 900th order." "It resembles the 10th Connoissance des temps [M10], which probably would put on the same appearance as this, were it removed half its distance farther from us."
Locating Messier 14:
Because M14 is rather small and on the faint side for small optics, it isn't easy to find in binoculars or a finderscope. The best way to start is to identify Delta Ophiuchi and begin about a handspan east. If you have difficulty, try about one third the distance between Beta and Eta Ophiuchi. Because of its relative size, it will appear almost stellar - but if you look closely, you'll notice that it's a "star" that won't quite come to a sharp focus.
With a minimum of 10X magnification, you can easily see that Messier 14 is a deep sky object and it will appear "fuzzy" to smaller telescopes and begin resolution with aperture of around 6". Large telescopes can fully resolve this loosely structured globular and can even distinguish some ellipticity in its general shape.
Here are the quick facts to help you get started. And as always, we hope that you enjoy your observations!
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Explanation: What forms lurk in the mists of the Carina Nebula? The dark ominous figures are actually molecular clouds, knots of molecular gas and dust so thick they have become opaque. In comparison, however, these clouds are typically much less dense than Earth's atmosphere. Featured here is a detailed image of the core of the Carina Nebula, a part where both dark and colorful clouds of gas and dust are particularly prominent. The image was captured last month from Siding Spring Observatory in Australia. Although the nebula is predominantly composed of hydrogen gas -- here colored green, the image was assigned colors so that light emitted by trace amounts of sulfur and oxygen appear red and blue, respectively. The entire Carina Nebula, cataloged as NGC 3372, spans over 300 light years and lies about 7,500 light-years away in the constellation of Carina. Eta Carinae, the most energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, but then faded dramatically.
Stargazing From the International Space Station: Astronauts aboard the International Space Station (ISS) see the world at night on every orbit — that’s 16 times each crew day. An astronaut took this broad, short-lens photograph of Earth’s night lights while looking out over the remote reaches of the central equatorial Pacific Ocean.
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2016 May 15
Explanation: In front of a famous background of stars and galaxies lies some of Earth's more unusual trees. Known as quiver trees, they are actually succulentaloe plants that can grow to tree-like proportions. The quiver tree name is derived from the historical usefulness of their hollowed branches as dart holders. Occurring primarily in southern Africa, the trees pictured in the above 16-exposure composite are in Quiver Tree Forest located in southern Namibia. Some of the tallest quiver trees in the park are estimated to be about 300 years old. Behind the trees is light from the small town of Keetmanshoop, Namibia. Far in the distance, arching across the background, is the majestic central band of our Milky Way Galaxy. Even further in the distance, visible on the image left, are the Large and Small Magellanic Clouds, smaller satellite galaxies of the Milky Way that are prominent in the skies of Earth's southern hemisphere.
“The world is the great gymnasium where we come to make ourselves strong.” -Swami Vivekananda
But what does it truly mean to be strong? We have four fundamental forces in the Universe: the strong, electromagnetic, weak and gravitational forces. You might think that, by virtue of its name, the strong force is the strongest one. And you’d be right, from a particular point of view: at the smallest distance scales, 10^-16 meters and below, no other force can overpower it.
Image credit: Sloan Digital Sky Survey, of IC 1101, the largest known individual galaxy in the Universe.
But under the right circumstances, each of the forces can shine. Up until recently, on the largest scales, we thought that gravitation — by and large the weakest of the forces — was the only force that mattered. And yet, when we look on the very largest scales, many billions of light years in size, even gravitation doesn’t win the day.
Image credit: NASA & ESA, of possible models of the expanding Universe.
“The fact that gravitational damping is measured at all is a strong indication that the propagation speed of gravity is not infinite. If the calculational framework of general relativity is accepted, the damping can be used to calculate the speed, and the actual measurement confirms that the speed of gravity is equal to the speed of light to within 1%.” -Steve Carlip
According to General Relativity, the speed of gravity must be equal to the speed of light. Since gravitational radiation is massless, it therefore must propagate at c, or the speed of light in a vacuum. But given that the Earth orbits the Sun, if it were attracted to the Sun’s position some 8 minutes ago instead of its present position, the planetary orbits would disagree with what we observe!
Image credit: David Champion, Max Planck Institute for Radio Astronomy.
What, then, is the resolution to this? It turns out that in relativity itself, what we experience as gravitation is also dependent on both speed and changes in the gravitational field, both of which play a role. From observations of binary pulsars, a gravitationally lensed quasar and, most recently, direct gravitational waves themselves, we can constrain the speed of gravity to be very close to the speed of light, with remarkable precision.
The quasar QSO J0842+1835, whose path was gravitationally altered by Jupiter in 2002, allowing an indirect confirmation that the speed of gravity equals the speed of light. Image credit: Fomalont et al. (2000), ApJS 131, 95-183, via http://www.jive.nl/svlbi/vlbapls/J0842+1835.htm.
“Science is the only self-correcting human institution, but it also is a process that progresses only by showing itself to be wrong.” -Allan Sandage
As April leaves us and May commences here at Starts With A Bang, I’m so pleased to inform you that amazing things are happening! Thanks to the support of everyone on Patreon, we’re over 95% of the way towards our next goal: the creation of the most accurate, beautiful, scientific timeline of the Universe’s history poster ever made! We’ve also covered the following topics this past week for you to ring in on:
Our Podcasts are coming along, too, as our Patreon supporters have chosen May’s topic (on dark energy), and someone, unsolicited (Philipp Dettmer, thank you!) has made me my first piece of fanart of me!
Image credit: Japan Meteorological Association (JMA), of the monthly average temperatures in February, going back as far as temperature records do. Via the Sydney Morning Herald at http://www.smh.com.au/environment/climate-change/true-shocker-spike-in-global-temperatures-stuns-scientists-20160313-gni10t.html?utm_content=bufferbc37d&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer#ixzz42sKWaHbp.
From Ragtag Media on climate tampering: “I back up my skepticism with not just my unabridged worldly opinion but with a variety of others.
Here, that this one: Massive Tampering With Temperatures In South America:
What you call “tampering” is what scientists call “adjustments”. Now you can say, “why don’t you just use the raw temperatures and be done with it,” but the reason is important: you are using these temperature measurements as proxies for the entire globe, and yet you are measuring them at limited, specific (often city-centric) locations located at ground-level. What do you do about the fact that paved roads increase (artificially) the temperatures you measure? What do you do about the fact that different stations give data with different quality levels? What do you do about fires when they occur nearby, or when factories are turned on vs. off?
If you say, “just give me the raw data,” you know you’re not accurately representing the global temperature. If you make the appropriate adjustments to the best of your scientific knowledge, how is that equivalent to “tampering” in any negative sense of the word? I’m going to say what I’ve said before to you: it sounds like you’re basing which argument you side with on the conclusions that are reached. If the temperature is warming, you refute that fact. If you accept warming temperatures, you refute that it’s human-caused. If you accept that it’s human-caused, you refute that it’s a bad thing. And if you accept that it’s a bad thing, you refute that there’s anything we can do. Remind me of where you are in that progression again?
Image credit: Breakthrough Starshot, of the laser sail concept for a “starchip” spaceship.
From PJ on slowing down a starshot: “Makes an interesting enigma – get to the target planet first, set up a power grid and laser site to slow the probes down on their arrival so that we can explore the local environment to decide where to set up our base.
The chicken and the egg again?”
Quite honestly, I think the conclusion we need to accept is not that we have to send a slowpoke-system to another star in order to properly explore it, but rather that sending a “starchip” starship to another system is just a cool technological feat on its own, and that the R&D that goes into developing the technology is fascinating and useful in its applications in a myriad of other ways. Think about the progress that will be made in:
light, strong, reflective materials,
laser technology,
laser collimation technology,
laser sail steering and stabilization,
miniaturization microchip technology,
and effectively 2D transmission and communication technology,
among others. We don’t need to get 100% of the way there to have something worth bragging about, or something that benefits society in a greater way than any individual efforts could do on their own.
A logarithmic chart of distances, showing the Voyager spacecraft, our Solar System and our nearest star, for comparison. Image credit: NASA / JPL-Caltech.
From Michael Kelsey on predicting the laser sail’s demise from collisions: “With an average interstellar density of a few atoms per cubic centimeter (1e-4 in hot, ionized regions to 1e+6 in molecular clouds), a solar sail with an area of 1 km2 at 0.2 c will see a flux of something like 6e+16 impacts per second, or a heat load of 192 kW.”
This is the main part of your estimation I’m unsure of. Your density numbers look good, your area looks good and your speed looks good. But impacts? I’m thinking of the famous Rutherford experiment, and the fact that if most of what we’re likely to encounter is ionized rather than neutral (and bound), most of these particles will simply pass through this thin sail with no collision at all. In other words, the number of impacts and the heat load may be many orders of magnitude lower than your estimate.
The concept art of a solar sail (Japan’s IKAROS project) at a distant planet or star system. Image credit: Andrzej Mirecki of Wikimedia Commons, under a c.c.a.-s.a.-3.0 license.
But I do wholeheartedly agree that each impact that does occur will not only be catastrophic as far as ionization (or even nuclear dissociation) goes, but a good fraction will conceivably result in e+/e- pair production as well. This is not necessarily going to be a happy, intact sail upon arrival is what I’m saying.
Jupiter and its rings, bands and other heat-sensitive features in the infrared. Image credit: user Trocche100 at the Italian Wikipedia.
From eric on the rings of the gas giants: “I am also amazed that the structures remaining after the ~5 billion years our solar system has been around, are structures that would be stable for >=5 billion years. What an amazing, miraculous coincidence. Oh celestial mechanics, you trickster you!”
There are a couple of important points to highlight: a fraction of the ringed systems present us with rings that appear to be truly stable, as they may exist for the remainder of the Solar System, while others require creation and shepherding by moons. The outer rings of Saturn — created by Enceladus and Phoebe — are of the latter type, as are the rings of Jupiter and Neptune. The main rings of Saturn, as well as the majority of Uranus’ rings, may be of the more stable type.
Image credit: NASA/JPL/Space Science Institute, of Saturn’s E-ring, with Enceladus as the brightest spot.
But, as Denier and Michael Kelsey rightly point out, that doesn’t mean it’s easy to determine whether Saturn’s rings are ~100 million years old, ~4.5 billion years old, any number in between, or whether these are even the first incarnation of rings around it. As we all need to remember, there are many things that erase the early history of our Solar System, and now that we’re finally here, all we can see are the survivors.
Image credit: Wikipedia / Wikimedia Commons user Qashqaiilove.
From Denier on the strong force: “Are the Color Force and the Strong Nuclear Force the same thing?”
Although there is a good discussion that follows Denier’s comment led by Michael Kelsey, I’d like to chime in a little bit as well here. The strong nuclear force is one of the fundamental forces, and it comes in two manifestations:
the binding force that holds mesons and baryons together through quark-gluon (or antiquark-gluon) interactions, and
the binding force that holds atomic nuclei together, through (virtual) meson interactions.
Color force is an analogy to help us visualize this. If we allow quarks to be colored red, green or blue, and antiquarks to be colored cyan, magenta and yellow, then we can arrive at a colorless combination by having either a quark-antiquark combo or a 3-quark/3-antiquark combo. (Or superpositions of those: 1-quark/4-antiquarks, 2-quarks/2-antiquarks, 6-quarks, etc.)
Image credit: E. Siegel, from his new book, Beyond The Galaxy.
You might imagine, from this, that there are six gluons, but in fact there are eight. (Because 3^2-1=8, which is a property of SU(3).) And while asymptotic freedom tells us that the strong force goes to zero at very short distances, it also goes to zero as soon as you begin moving away from a color-neutral entity. (I believe, IIRC, it scales as 1/r^6, which is why the strong nuclear force dies off so fast and we can’t have very large nuclei for long.) I wrote a longer piece on this a while ago called The Strong Force For Beginners that goes over some of this in more detail, that you may enjoy.
The four beams emerging from the new laser system on Unit Telescope 4 of the VLT. Image credit: ESO/F. Kamphues.
From Omega Centauri on guide stars, delays and adaptive optics: “Now how does the detector/computer combo, know which portions are delayed/advanced, from only looking at one image (unless its actually measuring the arrival time from a concentrated pule -which I really really doubt is possible)? Or is it just trying a bunch of perturbations and seeing what happens, or is their something really clever going on?”
The wonderful thing about light is that it always moves at the speed of light, so if you delay the light’s arrival time by a certain, known amount, you know exactly how much “behind” your moving mirror is the actual light. Take a close look at the snapshot below.
Image credit: Gemini Observatory – Adaptive Optics – Laser Guide Star, annotation by E. Siegel.
There’s a copy of the light being sent along the red path, while a fraction of the incoming light arrives at the purple path (at the bottom), telling us what the atmospheric distortion was at that moment. By time that red light arrives at the orange “distortion-removal” mirror, the purple signal has told the mirror what shape to be in to do the adaptation. As the next wavefront comes in, the mirror has adapted again. This adaptation is continuous and interpolated, and therefore imperfect, which is part of the inherent limitation of the technique. But the results are still amazing, and it kind of is like undistorting one snapshot at a time!
The effects of the Earth’s Atmosphere on the Telescopic Image of alpha Piscium from Edinburgh and from Alta Vista 10,700 ft., compared. From a 1863 engraving by Charles Piazzi Smyth, in the public domain.
From PJ on AO and giant telescopes for amateurs: “The best thing about the technology is that it will soon be possible for the backyard operator to run a similar setup in small scale. A 36 to 40 inch reflector in a dome is not out of the question in the near future. The cost of sodium lasers will eventually drop with demand. Quite a challenge, methinks.”
I hate to say it, but “amateurs” have had ~24″ telescopes at their disposal since the late 1800s, which is how Isaac Roberts took the very first picture of a galaxy beyond our own.
Image credit: Isaac Roberts, from A Selection of Photographs of Stars, Star-clusters and Nebulae, Volume II, The Universal Press, London, 1899.
The powerful sodium laser isn’t the most expensive part, either; the adaptive mirror is. If you can get your hands on that, the software is free, and the rest is up to you to put the whole configuration together. Jim Misti and Adam Block are two of the more famous astrophotographers I admire, and their “amateur” status is a testament to how much one can do with off-the-shelf technology!
Image credit: European Gravitational Observatory, Lionel BRET/EUROLIOS.
From See Noevo on the speed of gravity equalling the speed of light: “Must have been a slow news day in science.”
Some days, you report the news by talking about a new discovery (or new hype); other days, you make the news by talking about something that is known by the experts, but by bringing it to a level that non-experts can understand. Science is always happening, but science communication only happens as science communicators choose it. Hopefully you enjoyed learning about this!
Image credit: David Champion, Max Planck Institute for Radio Astronomy.
From Veri Tay on some blatantly untrue stuff: “Lol, gravity is instant, really all of modern so-called science is a bunch of lies. Primary light travels instantly – we see the universe in real-time.”
It must have been fun to just make all these authoritative sounding statements without any facts or evidence to back them up. If everything is instantaneous, why are there time delays in the arrival of everything from gravitational wave pulses to the arrival of New Horizons’ data from beyond Pluto to signals sent to-and-from the Moon.
Remember? Or at least, remember watching the footage of it? If you don’t, here’s what I want you to do. Take your cellphone and call your friend that you’re actually, physically with. Go have them sit in a car while you stand outside the car. Have a conversation with them on your cellphone and watch their lips move, and pay attention to when you hear their voice in your phone versus when you see their lips move. That’s your evidence, right there, that the Universe is not instantaneous.
And finally, from Naked Bunny with a whip on inhomogeneities: “I can safely say the water in my glass is of a uniform average density, even though most of the mass is concentrated into tiny nucleons surrounded by relatively vast stretches of space, and there are doubtless small temperature variations.”
One of my favorite analogies to use for the level of inhomogeneity in the Universe — and you can find this in my book — is the surface of the ocean. If you imagine the ocean, some 3 miles (5 km) deep, and surface level waves maybe 1-10 cm in magnitude, the differences between the peaks and troughs relative to the entire depth of the ocean is similar to the initial differences between overdense and underdense regions in the Universe.
Fluctuations in the ocean relative to fluctuations in the density of the Universe. Images credit: E. Siegel and the COBE satellite/NASA.
Over time, however, small scales have more time to gravitationally collapse, meaning we get greater density fluctuations on smaller scales today and smaller fluctuations, or smaller departures from the initial fluctuations, on the larger scales. That’s what we’ve got, and that’s consistent with what we expect!
Thanks for a great week, everyone, and I’ll see you back here tomorrow for more wonders of the Universe, more stories, more science and more Starts With A Bang!
“I am become death, the destroyer of worlds.” -J. Robert Oppenheimer
The nucleus of the atom holds many secrets, not the least of which is the key to the release of energy hundreds of thousands-to-millions of times more efficient than any chemical means known. In order to build and develop the first atomic bomb, a myriad of challenges needed to be overcome, including the ability to sustain a chain reaction among fissile materials.
The Uranium-235 chain reaction that leads to a nuclear fission bomb. Image credit: E. Siegel, based on the original public domain work by Wikimedia Commons user Fastfission.
The key to that was double-heavy water. And while we laud the Manhattan project scientists for figuring everything out, the truth is that Nazi scientists, led by Werner Heisenberg, had figured it all out, too, back in 1940. The invasion of Norway was led, in no small part, by the drive to acquire that deuterium oxide and the means of its production at the plant in Vemork. The plot to sabotage it — and with it, Hitler’s atomic bomb ambitions — is one of the most enduring stories of science, history and war in all of humanity.
Vemork Hydroelectric Plant at Rjukan, Norway in 1935. The heavy water was produced in the front building. Image credit: Anders Beer Wilse, in the public domain.
“A single day is enough to make us a little larger or, another time, a little smaller.” –Paul Klee
When it comes to normal matter, dark matter is a bit of a puzzle. Other than through the gravitational force, there’s no way we’ve yet figured out to make it interact. Try and collide it with matter and it passes right through; try and bombard it with energetic particles or radiation and it’s completely transparent. But the story is quite different when it comes to dark matter and black holes.
A black hole feeding off of an accretion disk. Image credit: Mark Garlick (University of Warwick).
While it won’t make an accretion disk or “funnel” into the black hole, once it crosses the event horizon, it inevitably hurls towards the singularity, adding to the mass and angular momentum of the black hole. But beyond that, there’s no way to know what went into your black hole, as what comes back out in the form of Hawking radiation will have no memory of how much dark matter vs. how much normal matter went into your black hole to begin with.
Image credit: Concept art by NASA; Jörn Wilms (Tübingen) et al.; ESA.
“The diversity of the phenomena of nature is so vast and the treasures hidden in the heavens so rich precisely in order that the human mind shall never be lacking in fresh nourishment.” -Johannes Kepler, and the adopted saying of the Kepler mission
The latest haul from NASA’s Kepler mission indicates that, in it sample of some 150,000 stars, there are over 2,000 confirmed exoplanets, with approximately 40% of them rocky worlds. If we extrapolate this to our entire galaxy, we have about 60 billion habitable zone planets in our galaxy alone.
The 21 Kepler planets discovered in the habitable zones of their stars, no larger than twice the Earth’s diameter. Image credit: NASA Ames/N. Batalha and W. Stenzel.
But there’s a big difference between habitable zone and capable of hosting humans as they are right now. The astronomy indicates that there are so many opportunities for life — and intelligent life — to arise, but how many of these chances are actually borne to fruition?
Artist’s depiction of the worlds found by Kepler thus far. Image credit: NASA/W. Stenzel.
“There’s no god, it’s the elements that control this world and everything on it.” -Scott A. Butler
From hydrogen through uranium and even beyond, the Universe gives us a huge variety of elements that can bond together in practically innumerable ways, creating all the matter we’ve ever observed in existence. Everything beyond helium in the periodic table way made inside of stars, but not all stars create elements equally.
Artist’s impression of the red hypergiant VY Canis Majoris. Our Sun will become a more modest red giant, but a giant nonetheless. Image credit: Wikimedia Commons user Sephirohq, under a c.c.a.-s.a.-3.0 unported license.
Our Sun will someday become a red giant, fusing not just helium into carbon, but creating elements that rise higher and higher in the periodic table. Yet there’s a limit to what even a red giant can create, as there are some elements that require a process our Sun will never know.
Two neutron stars colliding, which is the primary source of many of the heaviest periodic table elements in the Universe. Image credit: Dana Berry, SkyWorks Digital, Inc.
“It’s everywhere, really. It’s between the galaxies. It is in this room. We believe that everywhere that you have space, empty space, that you cannot avoid having some of this dark energy.” -Adam Riess
Back in the 1990s, scientists were quite surprised to find that when they measured the brightness and redshifts of distant supernovae, they appeared fainter than one would expect, leading us to conclude that the Universe was expanding at an accelerating rate to push them farther away. But a 2015 study put forth a possibility that many scientists dreaded: that perhaps these distant supernovae were intrinsically different from the ones we had observed nearby.
Two different ways to make a Type Ia supernova: the accretion scenario (L) and the merger scenario (R). These may be fundamentally different from one another. Images credit: NASA / CXC / M. Weiss.
Would that potentially eliminate the need for dark energy altogether? Or would it simply change ever-so-slightly the amount and properties of dark energy we required to explain modern cosmology?
A Type Ia supernova in the nearby galaxy M82. This one is fundamentally different from the one atop this page, observed in 2011 in M101. Image credit: NASA/Swift/P. Brown, TAMU.
Here I am / Rock you like a hurricane!” -The Scorpions
On Earth, category 5 hurricanes cause devastation wherever they make landfall, bringing sustained winds, rain, destruction and — in many cases — casualties. But despite how strong and massive these storms can be, they’re just peanuts compared to what happens on our Solar System’s gas giants.
Jupiter’s great red spot (from Cassini, imaged in 2000) and Earth (imaged from Apollo 17 in 1972), shown together for size comparison. Image credit: NASA / Brian0918 at English Wikipedia.
While Saturn’s north pole and Jupiter’s great red spot are powerful, sustained storms that are far larger than anything found on our world, a world-encircling storm on Saturn that raged for over 200 days from 2010-2011 broke all the records. At its grandest, it was large enough to contain 10-to-12 Earths.
Image credit: ESO/Univ. of Oxford/T. Barry, of Saturn’s 2011 storm in visible and various infrared wavelengths.
Přehled událostí na obloze od 16. 5. do 22. 5. 2016. Měsíc bude v úplňku. Večer je vidět Jupiter. Téměř celou noc jsou vidět planety Saturn a Mars, který bude v opozici. Aktivita Slunce se lehce zvýšila. Na Zemi přistál Dragon s materiály z ISS.
Jak jste se dostali k astronomii a kosmonautice? Nebylo to náhodou díky fascinujícímu svitu jasné hvězdy večer na západě, o kterém vám někdo pravil, že to je Večernice, planeta Zemi nejbližší? Nebo to bylo nad knihami, kde popisovali úžasná přistání sond Veněra i to, jak si s nimi drsné prostředí na Venuši pohrálo… Nebo vás přitáhl vzácný přechod Venuše přes Slunce? Planeta pojmenovaná po bohyni lásky určitě přitahovala lidi odpradávna. Ale to pravé zkoumání přišlo samozřejmě až s nástupem kosmonautiky a o tom hlavně bude náš seriál. Naší snahou bude přehled o výzkumu Venuše z pohledu astronomů, ale především pomocí kosmických sond.
Jestliže jsme nazvali letošní měsíce únor a březen z hlediska nově objevených komet jako velmi špatné, tak je nutné uznat, že duben dopadl naprosto tragicky. Nalezena totiž byla jen jedna jediná kometa. Znovuobjevený nebyl ani jeden kometární objekt. V dubnu objevená kometa byla zachycena dalekohledem PanSTARRS v první polovině měsíce, a proto je uvnitř jejího označení písmeno G.
