Starship Asterisk*

As far as I understand it, in General relativity gravity moves at the speed of light. People always seem to give the example that if you could magically remove the sun, the Earth would continue in its orbit as normal for the 8 minutes it would take for influence of its gravity to be removed, the 8 m...

I'm sorry Harry but you are wrong, essentially everything in your last post is mistaken. But thanks for playing. How can you say that the generation before were very massive and unlike anything seen today? Simple from dozens of lines of evidence we know tha the material produced in the BB was mostly...

Hi BMAONE23 Much of what you say is probably true, we know GCs could potentially be very important in the early stages of star formation. From the heavy elements that these objects have, we know that they formed as probably only the 2nd or 3rd generation of stars, and that possibly the generations o...

HI BMAONE23 GCs aren't thought to be "congealed" collections of stars. They are a collection of stars that formed from the same star forming region. All stars form in stellar nurseries, most slowly drift out of the star forming region over time, when GCs form there are so many stars formed...

Speaking as someone who works on Globular Clusters the distinction between GCs and dwarf galaxies is usually an arbitrary choice of mass, people generally say a bound collection of stars much larger than about a million solar masses is a dwarf galaxy, anything below is a star cluster. Theorists ofte...

The one you want is this one http://imgsrc.hubblesite.org/hu/db/2007 ... ge_web.jpg.

Its the same image but has the scaling changed so you can see the arcs more clearly in the inset. I work with the guys that made it, and it is pretty cool.

First off Orca, that was Cosmo, I'll leave it them to explain. Orin, not sure, seeing as you can only actually travel at c if you are massless there is actually no mechanism whereby you could send a signal back if you were travelling at c, so I think the answer may be according to the rules its impo...

There is no evidence to indicate expansion of the universe. Although we know that parts do expand and some parts contract. So which is it? No evidence of expansion, or expansion and contraction? Of course there is plenty of evidence for expansion but I can't be bothered to repost it for the umpteen...

Thats the point.

In an infinite (in extent and time) Universe there would be no gaps. There are only gaps because we can only see so far, and we can only see so far because the Universe is not infinite in age.

Hi Kovil Well the efficiency of our eyes is actually irrlevant in this argument. You can follow through the maths and prove that if stars are homogeneously distributed (on average) the surface brightness is equal to that of the Sun, so our eyes will see something as bright as the Sun. All the trilli...

Yes, the night sky is dark because the universe is finite , in what we can see of it. I'm not sure if you mean that the Universe is infinite (in time and extent, like Harry believes) but that we can only see a finite part of it. Because in an infinite eternal Universe we should be able to see every...

Its from the Digitized sky survey, which is based on photographic plates, so the things you are describing are most likely bits of dust or hair or scratches on the plate. The plates have to be digitized by a a machine that essentially scans them, anything on the plate at the time that happens also e...

iamlucky13 is right. Black holes are black not because they are big black balls (like a big ball of coal say) but because the mass they have is contained in a singularity. So from a very real perspective there is nothing to be seen, all we can see is the influence of the gravity of the mass containe...

The size they talk about is, I think, the size that can be inferred by the motion of the stars, this is not necessarily related to any physical scale of the BH, if there were stars that were closer to the BH, they could pin down its size more accurately. Ball park of course, but do the stars really ...

I mean its radius is 5 times larger, the sun has a radius of about 7 x 10^8 m. Though I still have my doubts until I have a look at the numbers with a real calculator. The gravitational force would still be huge at much greater distances than this number though, still plenty to keep those stars whiz...

Well technically the BH has no size whatsoever, it is a singularity, however people usually define a BH as having the same size as its event horizon (its Schwarzchild radius), the radius at which nothing not even light can escape. Rs = 2 x G x m / c^2 So in this case Rs = 2 x (6.67x10^(-11))x 10^6 x...

I think Orin means that we can only see light that directly passes into our eyes, so a thin beam of light passing us by is only visible if some light gets scattered away from the beam and into our eyes. Like in a laser pointer, where generally the beam appears to be invisble except where it strikes ...

The reason the sky is dark is actually one of the successes of the BBT, its because the Universe has a finite age, there just hasn't been enough time for enough stars to have existed for there always to be a star on any given line of sight. Also the expanding nature of space tends to spread out phot...

Hi all This section from wikipedia answers the question I think It is sometimes claimed that light is slowed on its passage through a block of media by being absorbed and re-emitted by the atoms, only travelling at full speed through the vacuum between atoms. This explanation is incorrect and runs i...

Michael you clearly do not know enough about Arps "techniques". His method is to look at interacting galaxies, those galaxies that are known to have tidal tails, in other words those that have bits of streams all over the place. His target galaxies are generally tens to hundreds of square ...

Eurg, just been watching the first of those videos you linked. I won't be bothering to watch the second, it is utterly rubbish. It reminds me most of one of those creationist videos where they totally misrepresent the truth. It amuses me at the start when it claims many astronomers now do not believ...

I notice that most of those links have the same poorly thought out reasons as ones previously discussed here. Including the infamously poor list of 30 reasons, we have previously discounted. I also believe that your name is on that list of people that object to the BB Harry. What "independent r...

In much the same vein as Harry here is an interesting link: http://www.astro.ucla.edu/~wright/lerner_errors.html Since Harry constantly posts links that are basically rip offs of Eric Lerners book "The Big Bang Never Happened", here is the rebuttal from a professional that actually underst...

Harry, NASA is not astronomy. The vast majority of astronomy is done with no input from NASA. Most astronomy is done from the ground where NASA has little or no input, and beside that, what do you think NASA is doing? Do you think NASA is at the forefront of some conspiracy to support the BBT? For w...

Your suggestion that the disk around the material might emit light is fine, but we don't even have any real evidence that massive sized BH's, complete with disks no less, even exist at this stage do we? It seems to me like we're simply throwing out ideas that happen to be consistent with our theore...