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Disconnecticus posted:I randomly saved it last night - is it bad files to post it somewhere for download? Doesn't seem like that big of a deal to post it
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| # ? Feb 16, 2013 18:35 |
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| # ? May 25, 2013 13:49 |
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Panstarrs now visible in the southern hemisphere. http://astrobob.areavoices.com/2013...some-good-news/ quote:Comet C/2011 L4 PANSTARRS is getting its second wind. Although slowly brightening all all along, a recent surge pushed it past the naked eye limit this week. The comet now shines around magnitude 4.5. If you live in the southern hemisphere, it’s visible near the horizon during both morning and evening twilight. If Panstarrs continues brightening at its current rate, it might defy more skeptical estimates and reach 1st or 2nd magnitude at dusk in a couple of weeks or a little brighter than the Big Dipper stars. That’s when sky watchers in the northern hemisphere will first see it.
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| # ? Feb 18, 2013 18:13 |
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Gif if the russian asteroid, crossposted from the spaceflight thread. And a simulation of the Tuguska airburst http://www.youtube.com/watch?v=HjJuMFQyNyw Micr0chiP fucked around with this message at Feb 18, 2013 around 20:10 |
| # ? Feb 18, 2013 20:08 |
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Comet Observations for Dummies, Pt. 1 - Naked eyes and learning the skies Interested in citizen science? Well you're in luck - studying comets is a field where amateurs can still make valuable observations. There's a variety of ways that one can study comets, but I'm just going to focus on observations that can be made simply with the naked eye or through a telescope. Visual comet studies are still important in the age of photography, if for the main reason that it was the primary method of studying comets since people first looked up at the stars. Although we can make beautifully detailed photographs, visual observations of the same objects allow us to correlate what we see to what we saw in comets before the advent of photography. For those of you not familiar with the night sky - start familiarizing yourself! You have about 2 weeks to learn the evening sky for Comet PanStarrs, and nearly 6 months for Comet Ison! That's plenty of time - you'll be able to pick out some of the brighter constellations after a night or two of looking. A little more difficult is estimating the angular separation of objects. The sky is measured in degrees, minutes, and seconds of arc, and visually estimating angular separation is sometimes difficult. There are a few rules of thumb (literally) that give you basic distances for the naked eye:  These hand gestures give approximate measures of angular separation in degrees when held at arm's length. Let's begin with your first exercise. Find Mercury and Mars. Here's a simple finder chart for February. Mercury is the object following the parabolic path, while Mars is the object cutting underneath it. Mercury is currently the brighter of the two, and is fairly easy to see in the sky just after sunset for the Northern Hemisphere. It won't be this way for long, as the amount of light Mercury reflects towards Earth is steadily decreasing as it becomes a crescent. Mars is a lot dimmer, and may not even be possible to see at this point. The point of this exercise is to train your eye to find dim objects in the sunset. Mercury is magnitude -0.5 this week, about one to three magnitudes brighter (2.5 to 16 times brighter) than Comet PanStarrs will be at its best. If you can spot Mars in the sunset, you're doing good, as it's magnitude 1.2 - about the absolute brightest PanStarrs will get. As Mercury sinks into the sunset, it will fade lower than -0.5, but once you find it, you can follow it on successive evenings. Knowing where to look will make it easier to find, even as it gets dimmer and deeper into the sunset. This will help with PanStarrs later on, as it will be brightest deep in sunset and dimming as it moves away from the sun. Once Mercury and Mars set, don't go back inside just yet. Continue training your eye with another set of exercises that will be useful later on - see how soon you can find the brightest stars in the darkening sky. Once it's fully dark, start learning the constellations if you haven't already. If you're a quick learner or can find patterns really well, it shouldn't take long to recognize the brighter constellations. After a couple nights of practice you can usually find your way around the big ones without much trouble. Right now a good and bright constellation to look for is Orion, and that's probably a good jumping off point trying to learn the surrounding constellations. Another good thing to do in the weeks while we wait for PanStarrs to round the sun is to learn to estimate magnitude of stars in a dark sky with your naked eye. A star atlas (very handy to have when learning the sky) will give the magnitude of stars to the nearest magnitude, usually by making brighter stars larger on the atlas. Learning the stars and their apparent magnitude will be the most helpful guide for the first week to week and a half after PanStarrs appears in the sunset. Brightness observations can be reliably made only with the naked eye or binoculars during this time period. Naked eye and binocular estimates will also be of some importance throughout the encounter, but early March is the time for naked eye astronomy to shine.  The sooner you start practicing at finding objects in the sunset, the better you'll be when PanStarrs makes its entrance. My next post will cover telescopic observations, and I should get that written up in the next few days. Feel free to ask any questions and I'll answer them to the best of my ability. If you want to take photographs but don't know how, I'd recommend asking your fellow Goons over in the Amateur Astronomy thread in DIY. They're pretty good at astrophotography, which is something I've only dabbled in and never been good at myself.
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| # ? Feb 20, 2013 04:17 |
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Brilliant stuff! I can see due west from my living room window, turned around eagerly to practice...drat you overcast! 
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| # ? Feb 20, 2013 17:53 |
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Good news everybody, PanStarrs was photographed in the sunset from the Southern Hemisphere with only a 3 second exposure - meaning it's fairly bright. Judging by the photo it's currently about magnitude 4. The photographer, Chris Wyatt, was not able to see it through binoculars, but that might be a function of it being very low on the horizon (~2.6 degrees) and the fact that he was using 7x50 binoculars on a very hazy horizon, both of which reduce the contrast. Here's a link to the photograph (rehosted by me so I don't end up blowing the original host's bandwidth). As you can see, it's kind of difficult to pick out, but the fact that it's even visible at all with such a short exposure is a good sign. Based on its performance this last week it'll probably be fainter than the -1 magnitude originally predicted, but it's probably a safe bet that it'll be in the 1-2 mag range by the time it pops out into the sunset here in the Northern Hemisphere. Also, I forgot to mention we're dealing with a waxing moon at the moment, so your ability to learn the fainter stars currently up in the evenings will be hampered somewhat for the next week and a half. However, this is perhaps a very good time to also learn sketching faint objects despite moonlight, which will be a factor about a week and a half after PanStarrs rises out of the sunset. I'll have a tutorial on that written shortly. Venusian Weasel fucked around with this message at Feb 21, 2013 around 00:40 |
| # ? Feb 20, 2013 22:08 |
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Awesome. With a bit of a hike I have a clear ocean view to the west and the weekend of March 9/10 is very near the new moon. And I'm off work. If the weather is good, I'll try some pics around sunset.
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| # ? Feb 20, 2013 23:29 |
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http://www.sott.net/article/258563-...n-Starrs-Updatequote:Comet Pan-STARRS (C/2011 L4), widely expected to become a naked-eye object in early March, is now closer to the sun than Venus. Solar heating is vaporizing the comet's icy core and creating a wide, fan-shaped tail visible through binoculars in the southern hemisphere. Ignacio Diaz Bobillo sends this picture from Buenos Aires, Argentina:
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| # ? Feb 21, 2013 23:04 |
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I saw that on SpaceWeather the other day. That's actually C/2012 F6 Lemmon, which will be putting on a respectable show (4th or 5th magnitude) for the Southern Hemisphere until mid-May or so. It'll be fading by the time it gets far enough for us northerners to see it, but it'll probably still be in the 6th or 7th magnitude range, which is still a nice sight through a telescope.
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| # ? Feb 22, 2013 00:56 |
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Well done for clearing that up! My comet source checking facilities are severely lacking. At least it's a pretty picture!
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| # ? Feb 22, 2013 01:14 |
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What happens when an asteroid crashes into the sun? I know the sun is gigantic beyond comprehension, but some space rocks are pretty big, and moving extremely fast.
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| # ? Feb 22, 2013 02:40 |
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I'm pretty sure you could crash a planet into the sun and it wouldn't really notice.
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| # ? Feb 22, 2013 02:51 |
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Sammus posted:What happens when an asteroid crashes into the sun? I know the sun is gigantic beyond comprehension, but some space rocks are pretty big, and moving extremely fast. Nothing. It burns up. It wouldn't even be observable. The sun is unbelievably big and hot, and asteroids are not very big. Take this picture of the sun: http://en.wikipedia.org/wiki/File:S...tting-scope.jpg . Those sunspots are several times larger than the Earth.
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| # ? Feb 22, 2013 02:57 |
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This page has a comet evaporating into the sun (the yellow video) http://www.nasa.gov/mission_pages/s...treaks-sun.html Its not exactly spectacular.
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| # ? Feb 22, 2013 03:01 |
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Uncle Jam posted:This page has a comet evaporating into the sun (the yellow video) It's technically impressive that we're able to record a 20-50 meter object being vaporized less than 1 million km from the surface of the sun. I'm sure astronomers from the past would have killed for that capability. What we can get with space-based solar telescopes and coronagraphs is a huge improvement over what we had only 40 years ago. Here's an image of Comet Ikeya-Seki, the brightest comet in the last century, taken near perihelion in 1965:  Now, compare to the slew of images as Comet Lovejoy (a bright sungrazer in its own right, but still nearly a few orders of magnitude fainter) skirted around the sun in December 2011. I don't have a lot of time to write stuff tonight, but I'll hopefully get around to writing a telescopic observing guide this weekend. In the meantime, here's a few interesting sites relating to comets: Gary Kronk's Cometography - Gary Kronk is a dedicated comet observer, and is a leading historian on comets. There's a few hours of reading to be had in the "Memorable Comets of the Past" and "Sungrazing Comets" pages. Most bright comets have a listing of the discovery circumstances, interesting events that occurred while they were visible, and other neat little tidbits. Sungrazing Comets - A site dedicated to comets discovered by or visible through the Solar and Heliospheric Observatory (SOHO). There's some good articles about what happens to comets as they near the sun. There's also a nice set of links for anyone interested in discovering a comet at home through SOHO data. Seiichi Yoshida's Comet Page - A Japanese comet observer who collects observations of currently visible comets and plots light curves of the data. A good place to get predictions of how bright a comet may get. Skyhound's Comet Chasing - A good resource for telescopic finder charts for comets. Comets Mailing List - An English-language mailing list run by German comet scientist Maik Meyer. The focus of the site is on recent observations of comets, but there are a few good how-to guides and other historical tidbits squirreled away there if you care to dig for them. A bunch of noted comet discoverers and scientists post to the list on occasion, including Alan Hale (of Hale-Bopp fame), Terry Lovejoy, and John Bortle. The German Comet Section - A website run by German observers, but has an English page. A good place to find the most recently reported brightnesses of comets and pictures taken fairly recently.
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| # ? Feb 22, 2013 03:41 |
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HopperUK posted:I'm pretty sure you could crash a planet into the sun and it wouldn't really notice. Truthfully, you could crash everything in the solar system into the sun and it wouldn't really notice. Nothing really short of another star would have an effect on the sun.
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| # ? Feb 22, 2013 06:03 |
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Will we get a good view of either of these out in the middle of the Pacific? (Hawaii mostly)
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| # ? Feb 22, 2013 06:28 |
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Paco de Suave posted:Will we get a good view of either of these out in the middle of the Pacific? (Hawaii mostly) I think so. You might already be able to see PanStarrs, and you should have a decent view of it until about late May, where it'll be visible all night, but low in the north. One thing I'm not sure about is that it might be a little slower to climb out of the twilight on successive nights due to your more southerly location. As for ISON...it should be visible from both hemispheres until it makes its hairpin turn around the sun, but it rockets almost due north after that. You should at least have a good seat for the show for the duration of its naked-eye apparition but it'll be getting low in the north by the end of December.
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| # ? Feb 22, 2013 06:57 |
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Rorac posted:Truthfully, you could crash everything in the solar system into the sun and it wouldn't really notice. Nothing really short of another star would have an effect on the sun. I'm pretty sure you could take every nuclear weapon on this planet, pack them all into a small space, and detonate them simultaneously, say, 1000 miles above the surface of the sun, and it wouldn't even be detected unless it was being looked for. (And even then it would be wholly unimpressive.)
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| # ? Feb 22, 2013 12:56 |
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quote != edit
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| # ? Feb 22, 2013 12:57 |
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Uncle Jam posted:This page has a comet evaporating into the sun (the yellow video) In Hitchhiker's Guide to the Galaxy, the rock band Disaster Area is putting on a special show where a spaceship crashes into a star. That comet is way more spectacular than the spaceship would have been. Not a very impressive show. But I'm sure Jupiter smashing into the Sun would look pretty cool and would be observable somehow (change in brightness?) with the naked eye on Earth.
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| # ? Feb 22, 2013 17:36 |
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Hipster_Doofus posted:I'm pretty sure you could take every nuclear weapon on this planet, pack them all into a small space, and detonate them simultaneously, say, 1000 miles above the surface of the sun, and it wouldn't even be detected unless it was being looked for. (And even then it would be wholly unimpressive.) Pretty much, slthough it probably wouldn't even get to 1000 miles, or even 10,000 without vaporizing. I'm honestly amazed that the second comet is going to go to .012 AU and survive. That's a little over 1.15 million miles (1 AU is almost 93 million miles). Note: Before somebody jumps to the logical conclusion, throwing nuclear waste into the sun is a terrible idea.
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| # ? Feb 22, 2013 23:44 |
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Rorac posted:
I don't mind jumping into this particular fiery pit. Is it a bad idea for other reasons than the energy it takes to get it there?
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| # ? Feb 23, 2013 00:44 |
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Ola posted:I don't mind jumping into this particular fiery pit. Is it a bad idea for other reasons than the energy it takes to get it there? A launchpad or atmospheric incident could be the worst thing in the history of human space travel.
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| # ? Feb 23, 2013 00:47 |
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redstormpopcorn posted:A launchpad or atmospheric incident could be the worst thing in the history of human space travel. Once we have the ability to get things into space without rockets it's not that bad of an idea though.
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| # ? Feb 23, 2013 00:59 |
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Right, that risk is a pretty good argument. I guess/hope/think we would discover economic fusion power before we discovered a way to ship our fissile waste to the sun safely and economically.
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| # ? Feb 23, 2013 01:02 |
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redstormpopcorn posted:A launchpad or atmospheric incident could be the worst thing in the history of human space travel. Yep, that's the prob. One little fuckup, and... Paco de Suave posted:Once we have the ability to get things into space without rockets it's not that bad of an idea though. There you go. I'd like to think I'll live to see this happen. Though I'd much rather see this happen first, instead. (Sorry, don't wanna derail; there's a thread or two devoted to this somewhere. I'll go find it/them.) edit: Well, there was a thread or two about LFTRs but I guess it/they have gone into archives now, sorry v  v.
Hipster_Doofus fucked around with this message at Feb 23, 2013 around 03:06 |
| # ? Feb 23, 2013 02:57 |
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It takes a ton of energy to hit the sun. You basically have to cancel out Earth's orbital velocity, which is something like 30 km/s. With the rockets we have, we'd have to use multiple carefully crafted slingshots around various planets. It would actually take less energy to hurl it out of the solar system into deep space.
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| # ? Feb 23, 2013 03:22 |
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How much mass would you have to eject from the planet to cause any dramatic effects in the orbit or what have you?
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| # ? Feb 23, 2013 05:25 |
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solaranus posted:How much mass would you have to eject from the planet to cause any dramatic effects in the orbit or what have you? If it lost mass without losing speed, it would not change its orbit at all, at least not the major factors. Things that depend on angular momentum would change, though, like precession. If the mass were removed (or added) in a way that changed the orbital speed, then the orbit would widen if it was going faster and make the earth cooler overall, narrow if it was going slower and make the earth hotter overall. Changes in the orbital eccentricity and/or axial inclination would change the seasons somewhat, and thus global air and water circulation patterns, hence the climate. Basically, the orbital mechanics of the earth depend primarily on how fast it's moving relative to the Sun and not on its mass. Any process that would change the Earth's mass would undoubtedly alter its orbital speed, however, so they're interrelated. Deteriorata fucked around with this message at Feb 23, 2013 around 05:45 |
| # ? Feb 23, 2013 05:42 |
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evensevenone posted:It takes a ton of energy to hit the sun. You basically have to cancel out Earth's orbital velocity, which is something like 30 km/s. Oh yeah, I keep forgetting... This not the first time I have re-learned that fact.
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| # ? Feb 23, 2013 22:15 |
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A few Panstarrs pics from the southern hemisphere. Taken by Minoru Yoneto on March 2, 2013 @ Queenstown, New Zealand  Taken by giovanni on March 2, 2013 @ paysandu , uruguay  Comets Pan-STARRS And Lemmon Taken by Michael White on March 1, 2013 @ SH 3, Manawatu, New Zealand Tons more pics here, all with big versions and EXIF data if you want to prepare for your photo trip: http://spaceweather.com/gallery/ind...fer_share=b56e7 I'm preparing as well, gone googling hod toddy recipes now!
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| # ? Mar 4, 2013 07:31 |
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For those of us in the northern hemisphere, expect to see the comet starting on the evening of March 7th. So in a few days, be ready to go to a place with few street lights. The best time to catch it will be during/after the sunset.
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| # ? Mar 4, 2013 07:42 |
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Am I right in thinking that Pan-STARRS has turned out a fair bit more impressive than anyone dared hope? Cos that looks pretty cool.
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| # ? Mar 4, 2013 08:54 |
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Hipster_Doofus posted:Am I right in thinking that Pan-STARRS has turned out a fair bit more impressive than anyone dared hope? Cos that looks pretty cool. If you have binoculars it's worth a drive away from light pollution to look at. Personally I'm hoping that the university next to me does an open house at their little observatory like they did during the Venus transit. Otherwise I'll probably wait for ISON and head out to my mom's place, which is both out in the country and where my good binoculars are located.
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| # ? Mar 4, 2013 13:19 |
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Ola posted:But I'm sure Jupiter smashing into the Sun would look pretty cool and would be observable somehow (change in brightness?) with the naked eye on Earth. Maybe a tiny photosphere burp related to convection & mixing, plus a nice-looking sunspot for a few minutes (?), but I don't think the brightness would change because Jupiter is less than a thousandth of a solar mass and therefore couldn't change fusion rates noticeably.
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| # ? Mar 4, 2013 16:47 |
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mdemone posted:Maybe a tiny photosphere burp related to convection & mixing, plus a nice-looking sunspot for a few minutes (?), but I don't think the brightness would change because Jupiter is less than a thousandth of a solar mass and therefore couldn't change fusion rates noticeably. Wouldn't all the gas form a comet-like coma?
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| # ? Mar 4, 2013 17:20 |
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The X-man cometh posted:Wouldn't all the gas form a comet-like coma? Yeah, probably. The stream would look pretty cool as Jupiter approached the photosphere (but would be tough to observe), since the solar corona would ionize a lot of Jupiter's hydrogen, but I think after coalescence things would be back to normal quickly. I guess it's possible it could cause a magnetic event and associated solar flare, but I don't think anyone has reliably simulated the magnetohydrodynamics of a gas giant impacting a G-dwarf star. There are some planet-formation models out there that deal with inward-migration of giant planets and the related blow-out of the gas layer, but naturally those folks don't care much about what happens at impact and beyond (not to mention the fact that we can't really build a working star in a simulation that behaves like a typical star as observed; heck, we can't even make them go supernova from first principles).
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| # ? Mar 4, 2013 17:29 |
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In the Northern Hemisphere (Specifically MURICA), when would be the best time to see/photograph Pan-STARRS?
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| # ? Mar 7, 2013 19:33 |
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| # ? May 25, 2013 13:49 |
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Soon!quote:March 12 or 13 will likely provide the first good viewing opportunity in northern latitudes, as Comet Pan-STARRS lingers over the western horizon at dusk [see illustration at right]. The comet will be viewable with the naked eye as it climbs higher in the sky throughout March, according to predictions issued by the Paris Observatory. But binoculars are always useful to help make out a comet’s tail or coma (the fuzzy cloud of dust and gas surrounding the nucleus), the visible features that distinguish comets from less-adorned asteroids.  http://blogs.scientificamerican.com...northern-skies/ edit: added this to OP with unfortunate wording letting my northern hemisphere bias shine through. Will endeavor to keep top of OP updated with current comet status. edit again: if you want to find out exactly when the sun sets in your area, use this: http://www.timeanddate.com/worldclock/sunrise.html Ola fucked around with this message at Mar 7, 2013 around 20:17 |
| # ? Mar 7, 2013 20:11 |
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