tag:blogger.com,1999:blog-22973357.post7460049224511017337..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: This and ThatSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger16125tag:blogger.com,1999:blog-22973357.post-42983932727039021432009-06-10T13:39:42.198-04:002009-06-10T13:39:42.198-04:00With these ultrahigh angular resolutions, a proble...With these ultrahigh angular resolutions, a problem that remains is the brightness of the sources. I was wondering whether a nova or supernova might illuminate the neighborhood enough, to e.g., be able to see planetary systems withing 25-50 light years of the nova.Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-7360329499898645642009-06-10T02:09:12.000-04:002009-06-10T02:09:12.000-04:00The ocean wave thing, at first hearing, sounds lik...The ocean wave thing, at first hearing, sounds like Landau damping*, or some similar mechanism in an appropriate phase space.<br /><br />*Been a few years, but as I recall, basically dumping energy into plasma by driving the particles near the appropriate cyclotron frequency.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-33549601626665610442009-06-06T14:07:07.739-04:002009-06-06T14:07:07.739-04:00Hi Stefan,
The earthly wave form that I find most...Hi Stefan,<br /><br />The earthly wave form that I find most fascinating and yet must admit being the most destructive is the Tsunami. It shows clearly how natural waves are in transmitting energy efficiently with little loss over great distances and leaves one less to wonder why when energy transfer is to be explained that the wave appears so much as being part of that description. <br /><br /Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-14696677704820025232009-06-06T11:56:44.743-04:002009-06-06T11:56:44.743-04:00Hi Plato,
Dvali’s proposal as to what accounts as...Hi Plato,<br /><br />Dvali’s proposal as to what accounts as being dark energy attributable to an extra dimension in which only gravity resides and leaches out to I find as intriguing yet hardly original. That is it's similar to a model which Lisa Randal has in the past proposed yet in this case only within the multi-verse perspective. <br /><br />I’ve often wondered if gravity is in effect aPhil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-15659196534751478762009-06-06T11:49:57.738-04:002009-06-06T11:49:57.738-04:00This comment has been removed by the author.Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49188763105975659332009-06-06T08:42:57.703-04:002009-06-06T08:42:57.703-04:00Just thought you might be interested since talking...Just thought you might be interested since talking about Moon and it's elemental distribution and all.<br /><br /><i>Dvali adds that the impact of modified gravity is able to be tested by experiments other than the large distance cosmological observations. One example is the <a href="http://physics.ucsd.edu/~tmurphy/apollo/apollo.html" title="" rel="nofollow">Lunar Laser Ranging experiment</aPlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-37061495433842216422009-06-06T06:53:24.446-04:002009-06-06T06:53:24.446-04:00Hi Stefan,
That was a very interesting article y...Hi Stefan,<br /><br />That was a very interesting article you pointed to on the use and progress of near IR interferometry. In reading about the problems with earth based setups the moon seems to be a better environment for such facilities. Perhaps when we go back this time we might be capable of doing more than collecting rocks, hitting golf balls and planting flags. It will indeed be Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21216694352843831552009-06-06T06:50:10.886-04:002009-06-06T06:50:10.886-04:00This comment has been removed by the author.Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-91756171575628059312009-06-05T21:16:43.055-04:002009-06-05T21:16:43.055-04:00Stefan, I suppose you were replying to my comment ...Stefan, I suppose you were replying to my comment below that of nige. In general, semantics underlies what people "see" and must be studied directly and worked around, not just taken as an obvious, natural background.Neil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-26439405663750550182009-06-05T17:42:34.763-04:002009-06-05T17:42:34.763-04:00Hi Arun,
oh, the proceedings volume "A giant...Hi Arun,<br /><br />oh, the proceedings volume "<a href="http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=9780521874700" rel="nofollow">A giant step</a>" you have mentioned is on <a href="http://books.google.com/books?id=dgfH6eBRjykC" rel="nofollow">google books</a> - great, cool tip!<br /><br />Cheers, Stefanstefanhttps://www.blogger.com/profile/09495628046446378453noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35528959830261005042009-06-05T17:32:26.422-04:002009-06-05T17:32:26.422-04:00Hi Michael,
Maybe these moon landing debunkers wi...Hi Michael,<br /><br /><i>Maybe these moon landing debunkers will be put to rest finally.</i><br /><br />Hm, but since the technique produces real images only after some mathematical transformations, that may not convince die-hard conspiracists ;-)<br /><br />Actually, Hubble has taken <a href="http://hubblesite.org/newscenter/archive/releases/2005/29/image/k/" rel="nofollow">photos of the Apollostefanhttps://www.blogger.com/profile/09495628046446378453noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-84828183608722749812009-06-05T14:37:52.218-04:002009-06-05T14:37:52.218-04:00Wave "interference" is a tricky term and...Wave "interference" is a tricky term and concept that misleads many, including physicists. First, amplitude addition (superposition principle) always applies regardless of phase difference. (Indeed, even waves "incapable of interference" such as with orthogonal polarization will combine to produce a wave with a new orientation.) This is one, fundamental meaning of "Neil Bateshttps://www.blogger.com/profile/04564859009749481136noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-30863922285972096012009-06-05T12:13:47.947-04:002009-06-05T12:13:47.947-04:00Might be fun to look at this bookA Giant Step: Fro...Might be fun to look at this book<a href="http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=9780521874700" rel="nofollow">A Giant Step: From Milli- to Micro- Arcsecond Astrometry (IAU S248)</a>.<br /><br />Since the Moon is about a lightsecond away, and the Sun is 8 lightminutes ~ 500 lightseconds away, microsecond resolution means we could see a man on the Sun!!!!!!!<br /><br />If only Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2463998040276006752009-06-05T12:01:12.954-04:002009-06-05T12:01:12.954-04:00Amazing! And from the Physics Today article "...Amazing! And from the Physics Today article "If issues associated with spacecraft stability and orientation perturbations can be adequately addressed, space-based interferometry has the potential to allow full-sky absolute astrometry at the microarcsecond level"Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-29632235331494095812009-06-05T08:09:47.263-04:002009-06-05T08:09:47.263-04:00Thanks for this post! It always amazes me to see h...Thanks for this post! It always amazes me to see how waves interact. You'd intuitively expect two waves colliding to destroy each other, but instead they add together briefly while they superimpose, then emerge from the interaction as if nothing has happened.<br /><br />Dr Dave S. Walton tried it with logical signals (TEM - trabsverse electromagnetic) waves carried by a power transmission nigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-65835489795527116052009-06-04T21:50:13.169-04:002009-06-04T21:50:13.169-04:00Performing some Fourier transforms results in imag...<i>Performing some Fourier transforms results in images with an angular resolution of milli arcseconds - enough to see a human on the moon, or to resolve the size and shape of stars.</i><br /><br />Now that's some fine work. Maybe these moon landing debunkers will be put to rest finally.Michael F. Martinhttps://www.blogger.com/profile/15279501532684851571noreply@blogger.com