Astronomy and Cosmology

As we know, stars are born when they fuse hydrogen, then continue with that long fusion process. This ignition would "seem" to come at a standard model size during the star's formation. So how do some stars like Eta Carinae, R136a1, and even larger stars get so huge? Is the answer simply that they keep sucking in more and more matter from the local system after the initial ignition? Simple as that? Or is the star's eventual size somehow determined during its initial formative stage? Thnx....

Hey Guys! Just recently was searching around for some cool astronomy info/images so 1. From the Mars Orbiter and also 2. Binary Star System Eta Carinae . Hopefully these images don't appear as massive as it looks like they will! Paul

How can I understand? "Speed increment at infinity" "Infinity" seems to be a speed measurement point, - by space probe trajectories, - but where is "infinity" http://en.wikipedia.org/wiki/Flyby_anomaly

You would think that any energy gained on the way IN would be lost on the way OUT. But the host planet manages to give up some energy. How ? Why ? Where exactly does the exchange or transfer of energy occur ?

I was recently sent a paper by a friend relating to The Red Shift Hypothesis for Quasars. He is an active geo-centrist and creationist and used it as a means of proof that the Earth is the center of the Universe. “The Earth is indeed the center of the Universe. The arrangement of quasars on certain spherical shells is only with respect to the Earth. These shells would disappear if viewed from another galaxy or quasar. This means that the cosmological principle will have to go. Also it implies that a coordinate system fixed to the Earth will be a preferred frame of reference in the Universe. Consequently, both the Special and General Theory of Relativity must be abando…

I've heard this several times before, but what about Saturn, Uranus, Neptune and the Asteroid Belt? It seems to me that we get protection from ALL those. Any comet coming from outside our solar system, that is moving on the plane of our solar system, must pass all those obstacles before hitting Earth. Especially the asteroid belt, since there are so many objects there that can hinder a comet with our name on it. I left out Mars, since it is so small compared to the others I mentioned above. But even Mars and the Moon could possibly take a hit for us.

http://en.wikipedia.org/wiki/Van_der_Waals_equation the VDW modifications, to the ideal-gas-law equation-of-state, imply that pressure is reduced, by attractive particle-particle interactions... in the fusing centers of stars, plasma particles are attracted to each other (at close range)... so, according to the VDW equation-of-state, at some density, those attractive nuclear forces could conceivably "deflate" the plasma pressure... could such actually occur, in the cores of stars ?? the VDW e-o-s: [math]P = n \times \left( \frac{k_B T}{1 - n \delta V}-n \delta V \epsilon \right)[/math] where [math]\delta V[/math] is the effective particle volum…

In her video, cosmologist and astrophysicist Laura Mersini-Houghton says the Planck Space Telescope has found evidence for multiple universes predicted by string theory. They are: Cold spot where 1/6th of the Cosmic Microwave Background (CMB) is empty. Suppression of the CMB at the largest scales. Monopoles, dipoles, and quadripoles aligned with each other (the so-called axis of evil). If this is so, it has to be the greatest scientific discovery of the century. So why isn't there more about this in the news? Video link: How to Find a Multiverse http://iai.tv/video/how-to-find-a-multiverse Link discussing this issue http://www.math.columbia.edu/~woit/wor…

Ever since reading Lawrence Krauss' book 'A Universe From Nothing', I've been very curious about something. We have apparently determined that the universe is flat, meaning that if a light beam (or presumably any other object moving in a straight line) will never return to where it began. And we also know that space is expanding. To properly convey what I want to know, I'll use a thought experiment. Let's say you blasted off from earth at trillions of times the speed of light, such that you were moving through space faster than the space in front of you was expanding. And let's for the sake of it discount any time dilation effects. My question is, what would happen ev…

This has been one that has puzzled my mind, at first I though it was because the images in our brain are yet projected backwards, however this seems not the case??? Another time I thought perhaps this was due to the close proximity on the earth's surface along with peripheral view. Maybe even having two eyes??? Still this has me quite puzzled as amusement rides such as roller coasters can make you feel backwards. Maybe it is the force of the roller coaster that does this or the natural laws of motion in general... Nevertheless, if the space shuttle in outer space lands on the earth, how and or why do the astronauts not feel they are hanging backwards????? …

Scientists can trace the age of the universe by measuring the current expansion of it. They can do this by measuring how quickly galaxies are moving away from us. When they "rewind" this math, it leads them to the big bang. According to this theory, the universe before the Big Bang was an infinitely dense point. So here's my question: If black holes are created when the Schwartzchild Radius of an object is reached, wouldn't the universe before the Big Bang just me a super massive black hole? Surely the Schwartzchild radius of the universe is unfathomably larger than anything we can imagine. Also: If I am right, and the pre-bang universe was a super ma…

Hello, I am wondering about the expansion of the universe and how it is expanding faster the farther we look out into space. If the farther we look into space the earlier back in time we see, doesn't this mean we are seeing the very distant galaxies, that are moving away from us faster than closer galaxies, at the velocity they USED to be moving away from us. In other words, wouldn't the closer galaxies be a better representation at the speed the galaxies are moving away from us because we are not looking so far in the past and that the expansion has actually SLOWED. I'm probably missing a fundamental point here but thanks!!

All the planets in our solar system formed at the same time 4.5 billion years ago. However, does this mean they all went through the same evolutionary periods at the same times? What if Mars finished forming before Earth, and Venus after Earth? Maybe Venus is still developing?

I weigh 80kg here on earth. Suppose I travel to a planet that is twice the size of earth, and twice the mass. Assuming an honest scale, what would I weigh on this planet? The knee-jerk response of 160kg is almost certainly wrong — that would make sense if the planet were earth-sized but still twice the mass. But if we start from there and use Newton's (or is it Hookes' ?) inverse square law, then for a planet twice the size, twice the mass of earth wouldn't the scale read (½)² = ¼th of 160kg, or 40kg? Intuitively, that doesn't make much sense. I understand the universe is under no obligation to satisfy my intuition, but am I even right in my calculations?

I'm just curious, but what are some sizes, filters and such does everybody use, if so.

hi first sry for my bad English, Why sky is black at nights ? I mean if we have millions of stars and all of them are shining then why night's sky is not like a giant lamp? I heard that its because of black holes, but I don't know if that's true.

Is there anything about Voyager that an intelligent ET could detect, that would make it stand out against other objects in space? Is there something about it that if ETs had the technology that they could scan space and notice something unusual about Voyager?

Is it known if all bodies there orbit in the same direction as the planets ? Is too much of a coincidence everything in the solar system orbits in the same direction, or is there a reason ? If an old planet existed in the asteroid belt and collided with a counterdirection 'visiting/errant' body; would that create an asteroid belt ?

Was there a time when the planets in our galaxy were closer to the sun than they are now?

Why is it that some people are still skeptical that extraterrestrial life is more than science fiction? I mean in a sense, it is impossible that it doesn't exist. To prove my point, let's assume (even though this is not always the case) that each of the universes 100 billion galaxies has 200 billion stars. Now, there are two possibilities for each of these stars; either they have planets with life or they don't. That means that the odds of every star in the universe besides the Sun having no planets with life on them is; 2 ^ (200 000 000 000 stars X 100 000 000 000 galaxies) : 1 There is no calculator that can even do that calculation. In my opinion that basic…

Hi, My question is the following : Consider two observers, in the univers, who have no speed in their comoving reference frame. They see their univers having the same age, but they are very far from each other, a distance almost as big as their visible univers. Other objects they see (stars) are at various distances. What is the form of the transformation that apply to coordinates of other objects they both see, (including the effect of the expansion) ? And can it be compared to transformation of speed in special relativity [ something like v' = v+w / (1+(w*v)) where speed are expressed in fractions of c ] To simplify the problem, we can co…

- as one headline catchily puts it! Any videos or interesting articles on this spectacular event folks? I have a BBC Horizon programme to watch on this, aired last night -- so that prompted me to open this thread. I haven't been able to skim every/all prior posts within Science. net, so apologies ahead if I double-up at any time... nb- I still haven't quite got the hang of the site's cut and paste facility. I gather we have to save our files initially, and then upload using the tools below, as cut/paste directly into here is not possible?

http://www.sciencedaily.com/releases/2013/07/130705101626.htm http://www.sciencedaily.com/releases/2013/07/130705102031.htm are those authors saying, that "radio bursters" are somehow similar to (long) "gamma-ray bursters" ? i.e. that the two are somehow part of the same spectrum of space phenomena ?

Just saw another UFO today an hour and a half ago. It was white, I think. It was around sunset time. It was stationary, and it wasn't there only a half-hour later.

What, according to the laws and physics of the universe, could exist on the other side of a black hole? There is a theory stating that due to the extreme density inside a black hole, a singularity of matter is formed, becoming so dense that it punches a hole in reality. Is this possible?