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This SpaceX / NASA launch is a big deal, right? We’ll ask an astronaut who knows - Ars Technica
Karen Nyberg will be watching the Crew Dragon mission closely—her husband is its commander.
33 with 28 posters participating Next week is finally looking like the time when American astronauts return to the International Space Station on American rockets. For nearly a decade, NASA and the US space industry have been relying on Russia and its Soyuz rocket for rides to and from the ISS. But ever since NASA awarded Boeing, Sierra Nevada Corporation, SpaceX, and Blue Origin development agreements in spring 2011, the hope has always been that one of these private US companies might become the country's next space-taxi service (the first private company to do so). SpaceX has reached the launch pad before its competitors, and now many space enthusiasts will be eagerly watching what happens on May 27 when the company's Falcon 9 rocket is set to take off from Kennedy Space Center at 4:32pm ET (20:32 UTC). Recently retired NASA astronaut Karen Nyberg knows the anxiety and excitement of launch day quite well. She served a total of 180 days in space in 2008 and 2013, flying into orbit both on the space shuttle and Soyuz vehicle. To prepare for her six-month stint to the ISS, Nyberg spent months learning the Russian language and traveling to Russia and Kazakhstan, even as it kept her away from her young son. And next week, she'll be keeping a particularly close eye on SpaceX and NASA's big launchher husband, fellow astronaut Doug Hurley, is the commander of SpaceX's first Crew Dragon mission. Crazy and exciting all at the same time, right? This Thursday, May 21, at 2:30pm EST (18:30 UTC/11:30am PT), Ars Technica Senior Space Editor Eric Berger will sit down with Nyberg to discuss the personal and professional challenges in facing the unknown in our next Ars live chat. They'll talk about her career, how she and Doug met as astronaut candidates, what it was like to raise a son while in space, and her feelings in anticipation of this high-profile, upcoming mission. In this socially distant, video-chatted conversation, Nyberg will field questions from Ars and readers to help us understand how monumental this moment could be and how Herculean the task of heading to the ISS still is in 2020. The discussion will happen through the livestreaming app Periscope and will be hosted on the Ars Technica Twitter account (@arstechnicayou can certainly @ us with questions). But we'll also embed the video below once things get underway for those who prefer to sit tight onsite. In the meantime, let us know what you'd like to ask by sharing the most urgent questions on your mind in the comments below.
Apple just announced one of its biggest regional expansions for the App Store ever - Ars Technica
The company is also holding an accessibility Web session for developers.
Apple says that Apple Music will now be available in 52 new countries, and other services including App Store, Arcade, Podcasts, and iCloud will hit 20 more countries.Users in the countries that are getting Apple Music for the first time will be offered a six-month free trial option. Also, Apple will extend its efforts to curate locally relevant playlists to these countries with titles like Africa Now, Afrobeats Hits, and Ghana Bounce. That brings the total count for the App Store to 175 and Music to 167 out of the 193 United Nations-recognized countries in the world. If you want to see the full count, Apple has a support page that lists which Apple Media Services are available in which countries.Apple made the announcement to the press via its newsroom website and to developers via its developer support portal. Apple maintains a page of resources for developers dedicated to localization efforts, and from what we've heard from developers, the company often makes an effort to prioritize promoting apps that are widely localized because of the global reach of Apple's platforms and services. And since we're on the topic of developers, here's a side note that also just happened: Apple yesterday sent invitations to members of its developer community inviting them to an online session dedicated to implementing accessibility features in apps. The invite reads: At Apple, we believe that technology is most powerful when it empowers everyone. Join us for an online event to learn how you can take advantage of the award-winning accessibility features that come standard on Apple devices. Youll be able to ask questions during and after the sessions, and sign up for individual consultations. The session will take place on Thursday and precedes the company's developer conferenceat which it normally offers many sessions like thisin June. The developer conference will be online-only due to the COVID-19 pandemic.
Finally, you can build an entire “game” out of Super Mario Maker 2 levels - Ars Technica
Key feature hits after nearly five years, complete with new items and enemies.
6 with 6 posters participating
- The individual level will no longer be the core unit of measurement in Super Mario Maker 2.
- Lots of customization options to pretty up your world map.
- You can set a unique icon for each level.
- The slot machine bonus game from Super Mario Bros. 3 makes a return.
- There are a variety of visual themes for your world maps. Here's Underground...
- With the "SMB2 Mushroom," you can ride on top of enemies and even pick them up.
- The "Mario as Jesus" parallels are almost too overt.
- The P-Balloon was one of the least enjoyable items in Super Mario World, but now you can change your angle...
- He floats through the air with the greatest of ease...
- Your throwing stick stunt has boomeranged on us.
- New headwear! But only in the Super Mario 3D World levels...
- I've had nightmares that look a lot like this.
- Mechakoopas are back, and now they shoot missiles.
- Super Mario Bros.: An "SMB2 Mushroom" that lets you ride on top of enemies and pick them up. Not quite the Super Mario Bros. 2 game style we might have been hoping for, but it should allow for some good course variety in any case.
- Super Mario Bros. 3: The Frog Suit gives Mario the usual high-jumping and fast-swimming powers, plus the new ability to run on top of the water's surface.
- Super Mario World: The Power Balloon makes Mario float, now with the ability to also change his angle in mid-air. Ho-hum.
- New Super Mario Bros. U: The Super Acorn lets Mario drift as a flying squirrel.
- Super Mario 3D World: The Boomerang Flower lets Mario throw boomerangs, as you might expect.
We may have seen two asteroids annihilate each other in another solar system - Ars Technica
What we thought was a planet appears to be gradually fading from view.
Enlarge/ The incredible vanishing exoplanetwhat models suggest we'd see as the debris of a collision diffuses away. 33 with 25 posters participating, including story author We've not actually "seen" the vast majority of exoplanets we've found orbiting distant stars. Instead, their existence has been inferred based on changes in the light of the stars that they orbit. That makes the 20 or so we have imaged directly exceptional. Direct imaging typically requires a very large planet, which means this sample isn't entirely representative, but these planets do provide a unique opportunity for us to observe how bodies interact with each other and their environments in exosolar systems. But, if two researchers at the University of Arizona are right, we can scratch one of these examples off the list. They say that the supposed planet has vanished in more recent images, which indicates it was never actually there in the first place. Instead, they argue that we've been observing the debris of a smash-up between two very large asteroids. Well, it looked like a planet... How could astronomers have identified a planet that didn't exist? Well, it really looked like it did. Back in 2008, when scientists first announced its discovery, the planet Fomalhaut b seemed to be very much there. Consecutive images taken a couple of years apart appeared to show it orbiting, and its orbit took it through a disk of dust and frozen material that is exactly where we'd expect planet formation to take place. So, at first glance, everything looks good. But problems became apparent pretty quickly. For one, planets have sufficient gravity to create gaps in any disks of material that they orbit within. But the disk at Fomalhaut b appears to be remarkably unperturbed by what seems to be a giant planet within it. More problems came when scientists tried to image it in the infrared. Fomalhaut is a young system, meaning any planets there have formed relatively recently. And, based on the amount of visible light reflected by the apparent planet, it was a large gas giant, potentially far larger than Jupiter. That means the planet hasn't had much time to release the heat generated as material streamed in to form itand with a planet this size, there should be plenty of heat. Yet Fomalhaut b was invisible in the infrared when scientists looked for it. Combined, these facts limit the possible size of the planet to smaller than Jupiter. Further observations took the limit down to near Earth-sized, which is basically incompatible with the amount of light we see from it. So, people started considering alternative ideas about what Fomalhaut b might be, including a smaller planet with large rings or even simply a large cloud of dust generated by local events in the ring. The researchers behind the new work, András Gáspár and George Rieke, found a few additional images of Fomalhaut in the Hubble archive. And, in these more recent images, some strange things seem to be happening. The non-orbital, vanishing exoplanet The first issue was with the orbital solutions. Based on Fomalhaut b's position in the earliest few images, researchers were able to calculate its orbit and predict where it should be in future images. And, in later images, it was close to where it was predicted to be. But differences existed and got larger over time. By the last image they had where Fomalhaut b was visible, it had deviated significantly from its predicted orbit. When the researchers tried to figure out its actual orbit, they discovered it was unstableFomalhaut b was apparently leaving the system. The second was with the apparent planet itself. While it's difficult to resolve much in the way of details at this distance, Fomalhaut b appeared to be growing increasingly diffuse over time. The final issue was a relatively simple one: in the most recent image, the planet was gone entirely. That doesn't mean there's nothing thereit just means that whatever might be there has dropped below Hubble's ability to detect it. Assuming this data is all accurate, it's easy to accept Gáspár and Rieke's contention that none of this is consistent with Fomalhaut b being a planet. So what is it? Their favored explanation is a collision between two asteroids that are roughly 100km across. If the collision was energetic enough to obliterate the asteroids, it would produce a steadily expanding cloud of debris that could reflect enough sunlight to be visible to Hubble. Since the fragments would be small, they'd quickly lose the heat of the collision to space, explaining the lack of infrared. And their gradual dispersal would explain the expansion and eventual disappearance of Fomalhaut b. Finally, because the collision would alter the orbital trajectories of the ensuing fragments, this would explain why they were seemingly on a path to exit the exosolar system entirely. When did that happen? To find out whether this idea is consistent with the data we have, the researchers got hold of a software package that could model an expanding sphere of reflective particles, and they used it to produce estimates of what Hubble might observe over time. This produced images that were reasonably consistent with the actual images obtained by Hubble. Given the agreement, the researchers were able to use the model to trace things back to when the actual collision must have taken place. That indicated it had occurred shortly before the first Hubble image that indicated the planet was there. That, of course, would suggest we've been extremely lucky to have imaged the collision at all. How lucky? To find out, the researchers estimated the amount of material in Fomalhaut's disk and how many sufficiently large asteroids would be formed. From there, they calculated how often collisions might take place. While there was a pretty large range that depended on the assumptions used, it placed the frequency of sufficiently large collisions somewhere between 150,000 and half a billion years. So, if Gáspár and Rieke are right, we have indeed been very lucky. Obviously, there are lots of strange things going on in the Universe that we can't entirely explain, so there's a chance that an explanation that seems to make sense will turn out to be wrong. The key test will be to have Hubble or its successor make regular diversions to the Fomalhaut system to make sure that the seemingly missing planet doesn't reappear in the future. PNAS, 2020. DOI: 10.1073/pnas.1912506117 (About DOIs).
Einstein wins again: Star orbits black hole just like GR predicts - Ars Technica
After nearly 30 years, VLT's new observations show star moves in rosette-shaped orbit
34 with 28 posters participating It's been nearly 30 years in the making, but scientists with the Very Large Telescope (VLT) collaboration in the Atacama Desert in Chile have now measured, for the very first time, the unique orbit of a star orbiting the supermassive black hole believed to lie at the center of our Milky Way galaxy. The path of the star (known as S2) traces a distinctive rosette-shaped pattern (similar to a spirograph), in keeping with one of the central predictions of Albert Einstein's general theory of relativity. The international collaboration described their results in a new paper in the journal Astronomy and Astrophysics. General relativity predicts that bound orbits of one object around another are not closed, as in Newtonian gravity, but precess forwards in the plane of motion," said Reinhard Genzel, director at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany. "This famous effectfirst seen in the orbit of the planet Mercury around the Sunwas the first evidence in favor of general relativity. One hundred years later we have now detected the same effect in the motion of a star orbiting the compact radio source Sagittarius A* (SagA*) at the center of the Milky Way." When Einstein developed his general theory of relativity, he proposed three classical tests to confirm its validity. One was the deflection of light by the Sun. Since massive objects warp and curve spacetime, light will follow a curved path around massive objects. This prediction was confirmed in 1919 with that year's solar eclipse, thanks to Sir Arthur Eddington's expedition to measure the gravitational deflection of starlight passing near the Sun. The confirmation made headlines around the world, and Einstein became a household name. Enlarge/ The perihelion precession of Mercury. General relativity also predicted a gravitational redshift of light in the presence of strong gravitational fields. That was first confirmed with the measurement of a redshift in the starlight of a white dwarf star in 1954. The third test was the precession of Mercury's rather eccentric elliptical orbit around the Sun. Every 100 years or so, the planet's perihelion, or the point where it is closest to the Sun, drifts about 0.001 degrees, thanks to the gravitational pull of other planets. That effect is how astronomers eventually discovered Neptune. Astronomers had noticed some odd perturbations in the orbit of Uranus, and 19th-century French mathematician Urbain Le Verrier correctly deduced it was evidence for another planet; his 1845 prediction was observationally confirmed in September 1846. Le Verrier also attempted to model Mercury's orbit in accordance with Newtonian gravity, which was put to the test during the 1843 transit of Mercury. His model failed that test, and he suggested that, once again, the deviations might be due to a hypothetical as-yet-undiscovered planet even closer to the Sun, subsequently dubbed Vulcan. But over the ensuing decades, no confirmed observations of such a planet transpired. It was Einstein who showed that the Newtonian theory of gravity was incomplete. General relativity accounts precisely for the observed precession of Mercury's orbit. Enlarge/ This simulation shows the orbits of stars very close to the supermassive black hole at the heart of the Milky Waya perfect laboratory to test gravitational physics and specifically Einstein's general theory of relativity. If those key predictions of general relativity have already been experimentally confirmed, why are scientists so keen to keep on testing them? Well, there may be unique environments beyond our solar systemsay, the extreme gravity of a supermassive black holewhere the laws of physics might not be quite the same. SagA* is the perfect laboratory to study this, especially given the dense cluster of stars orbiting around it. One of those stars, S2, holds particular interest, since it comes quite near the black hole during its closest approach (less than 20 billion kilometers). Enter the folks behind the VLT, which first came online in 1998. The VLT team was able to detect the faint glow around the black hole as S2 passed by in its first observations of the star. About two years later, in 2018, they successfully measured S2's gravitational redshift, whereby the strong gravity of the black hole stretches the star's light to longer wavelengths as it passes. Infrared observationsusing the VLT's GRAVITY, SINFONIA, and NACO instrumentsshowed that how much the light is shifted matched precisely with the predictions of general relativity. Like the redshift effect, the precession of S2's orbit is tiny, meaning it requires longer observation times before astronomers can detect them. S2 completes an orbit once every 16 years. The team finally collected enough data points on the star's position and velocityover 330 measurements in allto precisely map out its orbit. And just as general relativity predicts, each time S2 passes close to the supermassive black hole, it gets a gravitational "kick," changing its orbit ever so slightly, so the orbital path forms that pretty rosette shape. Enlarge/ Artists impression of path of the star S2 as it passes very close to the supermassive black hole at the center of the Milky Way. As it gets close to the black hole, the very strong gravitational field causes the color of the star to shift slightly to the red. Color effect and size of the objects exaggerated for clarity. "Our previous result has shown that the light emitted from the star experiences general relativity. Now we have shown that the star itself senses the effects of general relativity," said Paulo Garcia of Portugals Centre for Astrophysics and Gravitation, one of the lead scientists on GRAVITY. The next phase will rely on the forthcoming Extremely Large Telescope, which should give scientists the ability to see much fainter stars near the supermassive black hole. "If we are lucky, we might capture stars close enough that they actually feel the rotation, the spin, of the black hole," said Cologne University's Andreas Eckart, another lead scientist of the project, thereby enabling astronomers to measure SagA*'s spin and mass as well as define space and time around it. "That would be again a completely different level of testing relativity." DOI: Astronomy and Astrophysics, 2020. 10.1051/0004-6361/202037813 (About DOIs).