Astronomy and Cosmology

MANY Jupiter-like exoplanets are much larger than they ought to be. Now one astronomer thinks he knows why. Since planets usually form at the same time as stars, astronomers can tell how old and therefore how hot and puffy the gas giants should be. But many of the recently discovered gaseous exoplanets are larger than expected. Eduardo Martin of the Institute of Astrophysics of the Canary Islands believes this is because the puffy planets formed from the gas and dust ejected when two binary stars merged. This would make the planets much younger than their hosts, which would explain their unusual heat and puffiness. He presented his findings at the American Astrono…

If earth's moon causes "rock tides", and "ocean tides", does it also induce tides into our atmosphere ? Would such atmospheric tides affect satellites in LEO ?

I have looked at the topography of Mars and have come to the conclusion that it was formed primarily by a cataclysmic event with Jupiter. I made a video to show basically what I am suggesting. Any thoughts?

If mass, embedded in space-time, were to be found to 'decay', and actually 'disappear' from space-time, thereby reducing spatial mass density, down towards the Critical Value, would that "balloon-inflate" space-time? If such a 'vanishing act' were to occur gradually, over cosmic time, would the "balloon" of space-time "just keep inflating", progressively "pushing back" & "procrastinating" the Big Crunch?? Could such a "matter decay" process be construed as consistent, with the claims that the expansion of spacetime is accelerating??? Would it be feasible, to solve the Friedman equations, for a spatial matter density, that not only decreased as a(t)-3, but also i…

I assume most have read of the possibility that the fine structure constant could be space varying. I know that considerable more observations are needed before any level of confirmation is obtained but i have a couple of questions. 1) the variation is supposedly space but not time varying; a space variant constant field (like an elevation field). Wouldn't inflation flatten out this field? Considering expansion, How could a space variant field not be time varying? 2) Several blogs allude to the "if not this value then we would not be here to ask the question" problem by stating that a varying fine structure constant would make life possible in certain regions of…

How big would a meteorite have to be to cause equal amount of damage as the nuclear bomb that was dropped on hiroshima?

For T < 104 K, the cooling curve of the ISM scales as ~T7 (Gaetz & Saltpeter 1983): P [ergs cm3 s-1] = -10-23 x nh x ne x (T/104K)7 And, since z ~ 2, the IGM has cooled from 10,000 to 4,000 K: From z ~ 6 to 2, Cluster gas continued to influence the IGM, maintaining its temperature through outflows. After z ~ 2, however, Clusters completely decoupled from the Hubble Flow, continuing to contract, compress, & heat Cluster gas. Meanwhile, the now isolated IGM, in the receding voids, began to cool radiatively. (Source: Majestic Universe [scientific American special report], pg. 8.) So, we seek to calculate the cooling, of the IGM, as a functio…

I watched this video http://www.youtube.com/watch?v=X4rv9BqTWzI&NR=1 and below in the comments one guy said that Brown dwarf stars take a lot longer than 14B years to move through the Main Sequence! Is this true? Im only basic about cosmology because i am a business student. Please explain simply and non-biased(non religious people making pseudo scientific claims to make me lose trust in science) I really think that big bang theory is true. please tell me its true... sigh, i dont wanna lose faith in science even if its empirical i searched up brown dwarfs and big bang in google and it came up with this!!!!!! are u kidding me? plz explain…

NGC 6287 is the oldest Globular Cluster in the Milky Way Galaxy. And, according to this article, the cluster's Main-Sequence Turnoff happens at a V-I Color Index of ~1.3. Then, according to this site, that V-I Color Index corresponds, according to the formula: [math]T_{eff} = \frac{9385}{0.95 + (V-I)} K[/math] to an effective surface temperature of roughly Teff = 4200 K. Finally, according to the appendix of Carroll & Ostlie's Introduction to Modern Astrophysics (1st ed.), that effective surface temperature corresponds most closely with Spectral Class K5, which has [math]M \approx 0.67 M{\odot}, L \approx 0.15 L_{\odot}[/math]. Such a sta…

Matter is obviously straight forward. I have my ideas on anti matter and dark matter but an not completely sure. Space has always been a fascinating topic for me so can someone enlightened on this topic provide some information? appreciate it

In big bang theory, is it thought that the universe was homogenous until a certain point in history? If not, why not and if so, at what point did it begin differentiating into different levels of density and why?

http://www.universetoday.com/85927/australian-student-uncovers-the-universes-missing-mass/ Still pretty sketchy on the details, as it states that the amount of matter existing is only double of what has been observed, so I am led to believe that maybe this is not meant to include non-baryonic matter, if that is even a valid hypothesis now. Filaments that are a million degrees celsius.

Alpher, Bethe, Gamow (1948) assumed that, during Primordial Nucleo-Synthesis, matter density varied as t-2. However, that is the Matter-Dominated Era solution. Yet, Primordial Nucleo-Synthesis occurred tens of thousands of years earlier, before the MDE, in the Radiation Dominated Era, when [math]a \propto t^{1/2}[/math], so that matter density varied as t-3/2. That could affect the physics. Also, at the super-early epoch, the universe was expanding at enormous speeds. Would not the 'redshift recessional velocities' have been huge, so that the 'effective gas temperature', 'swimming against the current', would have been allot lower, than the actual local T ? Couldn…

"The device will sit outside the space station, seeking to collect high-energy cosmic rays and space particles that have may have originated with the "big bang," which astrophysicists theorize created the universe. If so, the findings could help them understand the makeup and origins of the universe. Some scientists have expressed strong skepticism that the AMS will work, but others think it might become the greatest astrophysics tool since the shuttle took the Hubble Space Telescope into space. Even if it does not detect its primary goals -- big-bang antimatter and so-called "dark" matter -- the AMS's potential to analyze cosmic rays and particles is unparalleled and…

A light-year is defined as "the distance that light would travel through space, if there was nothing to slow it down". Does that imply, that, in the early universe, when the ambient matter density was much higher, that the index of refraction n > 1, and light traveled (slightly) slowly ??

Please, humor me here. A is car is moving through space at a constant rate of 50 mph by accelration on the gas pedal. You the remove your foot from the gas pedal. Does it continue to move at about a constant rate if acted on by minimal outside forces? And if it does continue at a constant rate with out the application of the gas pedal, what would happen once the force of the gas pedal is reapplied to 50 mph. Would the car then go faster, slower, or the same rate?

Milky Way Is Warped, Like a Beer Bottle Cap - Technology Review COMMENT: The authors link the arm around to the Scutum-Centaurus arm, but I wonder whether it links around, instead, to the Perseus arm ??

Dark matter, science's new threat to the universe. But what is it? Some people call it the anti-gravity. If this is true this means the universe should, theoretically, be shrinking instead of expanding. what do you think?

Hey I just wrote a basic article on space travel, and I just wanted yall's opinion on it. http://hubpages.com/hub/deepspace It was originally going to be a comedy article on cracked.com, but I scrapped it and went with another idea.

I was reading Fred Hoyle's SF novel "The Inferno". Its scenario is, the centre of our Milky Way galaxy has exploded and become a quasar. High-energy particles from the quasar are rushing towards the Earth. Scientists are discussing the potentially catastrophic effects these particles will have on the Earth. One scientist says, we shouldn't worry, because: "There is gas, interstellar gas, all along the plane of the Galaxy. The gas will act as an effective shield." Another scientist refutes this reassurance, by asking: "How much gas? Along a unit-column, what? A hundredth of a gram for a column with a cross-section of one square centimetre....high-ener…

Well nothing is infinite. So why would space be any different?

Hey everyone, I've heard that with many mechanical devices that we place into space, we first loop them around the Earth to build up velocity, allowing for them to 'rocket' out of our gravitational pull and to gain some momentum. I've also heard that light curves around gravity; since light is a form of energy, I was wondering if energy is uniformly affected by gravity as well. If so, would it be possible to slingshot a minimal amount of energy around, say, a star, and to have it 'recharge' and return to it's point of origin? This is some really sci-fi stuff, I realize, but I'm just curious if it's at all feasible. Thanks, Oddt

I was surprised to note that in this place of quality and higher learning that no one is speaking of 2012 and it’s spatial consequences or possibilities.Personally, I do not believe any of the speculations but do wonder just how advanced our forefathers were and why they would bother creating such a long term calandar. Do you consider the doomsday scenarios as bogus as I do or is there anyone who gives 2012 some serious thought? Regards DL

I was just wondering, what's preventing another big bang from happening right outside my window?

You know, just in case we ever get around to spending this unbelievably grand sum of money to pointlessly send a few families on a ten to twenty year fool's journey to a pointlessly incompatible star system a whopping several light years away. Iron rain showers in space! Well shiver me timbers.