Starship Asterisk*

The process of accretion involves accelerated mass. So it produces gravitational radiation. (Accretion always involves inspiraling matter.) It is the acceleration that matters. Spin a barbell and you produce gravitational radiation, despite the fact that the two masses remain at a fixed distance fr...

... NGC 5985 and NGC 6844 in a split field of view,
similar to astrometric images

Wow.. never imagined there's so many with their paths around Sun that close (relatively) to each other and all planets. We have decent idea about none of the PHA's (ones we have discovered/identified so far) colliding with Earth in next 100 years, I wonder, what's the probability of them hitting ot...

2. Are these GWs directional, like the EM waves emitted by rotation or "lighthouse-like" pulsars that emit radiation along their spin axes? I don't know if there are any directional sources. But most are likely produced by two bodies, and the propagation is substantially on the plane of t...

by the way we are lucky that gravity waves are polarized. If you try the same trick with sound waves, which are not polarized, you fail. Say you pick the acoustic noise in a room by subtracting signals at microphones A and B, then subtracting signals at microphones A and C, and hope to see a correla...

those who learned that the CMB means the cosmic microwave background now face memorizing that the GWB means the gravitational wave background. No detailed map of distinct sources so far, just the total buzz amplitude of 2,4×10⁻¹⁵ at the frequencies about 1/year (that translates to 76 nanoseconds in ...

is there an IR view of M24 and Large Sgr with dust frames half-transparent?

showing how close they are to the disk and to the bulge of the Milky Way

purple (technically, magenta). I agree that calling anti-green colour purple is outdated. Modern smartphones and even large monitors are no longer sRGB, they are UHDTV, which is closer to LMS cones of human retina. sRGB green was in fact lime-green, and so sRGB anti-green was in fact purple-pink. N...

https://asterisk.apod.com/download/file.php?id=47758&t=1 MAVEN's Ultraviolet Mars Image Credit: MAVEN, Laboratory for Atmospheric and Space Physics, Univ. Colorado, NASA APOD Robot wrote: Recorded by the MAVEN spacecraft's Imaging Ultraviolet Spectrograph instrument in July 2022 (left) and Janu...

https://asterisk.apod.com/download/file.php?id=47757&mode=view Wow; A lot of great photos in today's APOD Orin, that's a great image! :D I couldn't find it in the links of today's caption. Where did you find it? Anyway, Victor, I very much recommend the image posted by Orin, because it does a g...

Let's try to make head or tails of the colors of today's APOD, shall we? https://apod.nasa.gov/apod/image/2306/BeltofEverest_Mukherjee_960_annotated.jpg Let's begin with the Earth's rising (or setting) shadow during sunset (or sunrise). Well, shadows in clear weather on the Earth tend to be blue, r...

I wonder why the flash looks yellow-green (lime) Keep in mind that JunoCam doesn't take a "snapshot", but has its sensor readout synchronized with the spacecraft rotation. So it takes about a minute to collect a single image (there are four filters) as one axis is swept out. What that mea...

Just a thought of why the lightning is green instead of electrical white. On Earth Auroras are usually photographed green and are from Solar winds descending the magnetic poles. Jupiter's magnetic fields are ten times stronger than Earth. And this is near Jupiter's north pole. Could this wide green...

guest again wrote: ↑Sun Jun 25, 2023 1:31 pm Green lightning, blue thunder?

if this lightning was thick hot plasma channel, then it should be the colour of blue giants: bluish

I wonder why the flash looks yellow-green (lime)

Of course, in the end it is the amount of dark matter that determines which of these two massive galaxies, NGC 6872 or NGC 6876, is the most massive! Ann We have to use gravitation lensing to map the dark matter. JWST would see a lot of dim background galaxies… This little comma-thing in a pentagon...

I wonder why do the solar power cells look uneven-coloured? What do you mean by "uneven-coloured"? It's a monochrome image. Do you mean that they aren't a uniform intensity? Could be dust, could just be seeing reflections from the surface. _ de-anaglyph-PIA24547.jpg Can't be reflection fr...

I wonder why do the solar power cells look uneven-coloured?

...But I don't think the much smaller satellite galaxy IC 4970 has enough mass for that, even though there are two bright X-ray objects there. I would rather consider the huge NGC 6876 galaxy as the source... https://live.staticflickr.com/65535/52997744083_41e6450d4f_c.jpg biggg: https://live.stati...

My first thought looking at 2 arms, with straight long outer parts and curved-to-ring short inner parts: there was an explosion at the centre of the core, shooting out a pair of massive jets. The 2 jets left 2 star formation lanes. The differential rotation bended those lanes into spirals, but what ...

https://apod.nasa.gov/apod/image/2306/NanduMilkyWay_Bouvier_1080.jpg Wow. Imagine having such dark skies that you can see the Coalsack as the head of an enormous cosmic bird! APOD Robot wrote: Pictured here is not only a segment of the central band of our Milky Way galaxy, but, according to folklor...

Interesting. The indigenous peoples of Australia have a similar view of the emu in the sky - part of the creator spirits. The great river in the sky is where all the spirits reside. ? https://www.ayersrockresort.com.au/sites/default/files/2020-10/image002.jpg It's interesting that the indigenous pe...

"nowhere else in the galaxy" except here https://asterisk.apod.com/viewtopic.php?p=289252#p289252 NASA has also found a hexagon on Jupiter. https://www.jpl.nasa.gov/images/pia23559-jupiters-pentagon-turns-hexagon but no hexagon around the Noth pole, just a lightening on Dec. 30, 2020 http...

"nowhere else in the galaxy" except here https://asterisk.apod.com/viewtopic.php?p=289252#p289252 NASA has also found a hexagon on Jupiter. https://www.jpl.nasa.gov/images/pia23559-jupiters-pentagon-turns-hexagon but no hexagon around the Noth pole, just a lightening on Dec. 30, 2020 http...

So would those central stars with "increasing velocities" be falling inward toward the black hole on a straight course, or circling in toward it in a spiral pattern? if toward the black hole on a straight course means passing at tidal rapture distance than the chances are zero. All they m...