Astronomy and Cosmology

Would the presence of Oxygen in the atmosphere of a planet be an indicator of animal life? Without plants and photosynthesis the Earth's atmosphere would be devoid of Oxygen. Without plants there would be limited scope for animals. So would this connection be universal?

I risk to ask a dumb question... Why is adaptive optics better than image processing? I mean, if you know how to adapt a mirror, then you also know how to process image to obtain the same effect.. or? I also read something about a thing called "speckle imaging" but I am not sure if this is what I am talking about. I am not sure if 'guide stars' (natural or artificial) are used with this speckle imaging.

I am a student of science. I know that the compus works for magnetic field on earth.But I don't know the actual cause of this magnetic field.Compus always set in north and south direction. Sometime I thing ,Is there any magnetic hill on north or south poll?Or this is the cause of spin of the earth. But what is right description of this magnetic field?

Watching some images of Pluto and Charon (http://www.space.com/11431-photos-pluto-charon-moons-dwarf-planet.html), see that longitude lines have already been decided. Should be recent, as close photos are. What features are taken in account and who decides were to set longitude zero position ? I assume other planets have been already determined. I wished they had decided for a different method/scale instead of the same archaic/arbitrary 360 degrees on earth...

I've read that the gravity of Titan at the surface is about 10% that of Earth. Plus I worked out that the atmospheric pressure at the surface would be like being in about 20ft of water here on earth. So explorers wouldnt need a pressure suit (altho they'd sure need an oxygen and temperature suit!) So presumably human explorers would be able to 'swim' along through Titan's atmosphere at the surface? Have I got this right? GIAN

I am just beginning my educational journey in physics and I need a trusted mentor to guide me. I am intelligent and learn easily and quickly, but did anyone else feel overwhelmed with ALL of the knowledge out there, in the beginning?

The latest images from the New Horizons probe of the Pluto system has revealed a series of dark spots near its equator. Does anyone want to hazard a guess on what they could be? Impact craters, extinct volcanoes? http://pluto.jhuapl.edu/Multimedia/Science-Photos/pics/7-1-15_Pluto_Charon_color_hemispheres_annotated_JHUAPL_NASA_SWRI.jpg

Assuming for the moment that the technology will be available in the not-too-distant future, could the Earth's energy needs be met entirely by solar power one day? By this I mean having the Sun's energies directed from space down to us on Earth via microwave beams, say. As a follow-on question, are there any practical limits to how much energy could be harvested from the Sun? I have in mind an array of gigantic solar panels orbiting the Sun at fairly close quarters - the ever-present threat of solar flares and CMEs notwithstanding. But there may be other solutions about which I am entirely ignorant. Finally, is the physics concerning the above already in place, …

Black holes are described as losing mass (very slowly - unless hole is microscopic) by Hawking radiation. The CMB is all over, so black holes will gain mass from CMB radiation impinging on them. Presumably bigger black holes will gain more. Question - at what size will these mass changes balance?

My question is about the topic on the title. See first the original article. So My speculative question on the subject is in the sphere of Einstein General relativity applying to the problem. So we all now know that when light passes close to some massive objects its path is slightly changed from its original trajectory.That's called deflection. So How will this phenomena of light deflection due to ceaselessly moving different kinds of masses of different objects like stars planets galaxies clusters et.c . THROUGH spacetime continium constantly wraping its curvature in different manners eventually obscure our observation of aliens on their remote distant planet via our f…

Just reading up on the higgs. Since scalar fields have a value over every point in space, when space expands and more points in space are created, does that mean that the higgs field and its corresponding particle is the only particle of the standard model for which energy density remains constant and doesn't decrease as space expands? What does it mean when they say the higgs does not transform under Lorentz transformations? Is it independant of time? Also what does it mean to have a point in space, is it the mathematical 1 dimensional space time point or are points in space measured by a planck length? If it is the 1 dimensional point, since there is an infinte amm…

I was just reading over the horizon problem wiki. And the whole issue lies around the assumption the universe began anisotropic. I would have assumed the universe began isotropic and the problem would be reversed, why isn't it still exactly isotropic? There a numerous semantic and logic failures in the article too. Oxymorons such as "almost precisely". And "extremely isotropic". Why alter an absolute? Things are either precise or isotropic or they are not. The absolutes are required for the argument to be effective. I can look around myself and see the universe is anisotropic. http://en.wikipedia.org/wiki/Horizon_problem#Basic_concept "This presents a serious proble…

I just got myself lost in The Standard Model. I started with trying to understand why baryon number must be conserved and why protons can't decay, then confused the hell out of myself as to why mesons can exist then, if solitary quarks cannot. Anyway since my heads spinning with this mess of a model, I want to ask the original question I was trying to answer. If we could reduce all particle types down to their minimum constituents, which particles would remain? If these particles were the only ones in existence at the moment of the big bang, would they be capable of forming the makeup of particles in the universe we see now? E= Mc^2 shows that matter and energy are …

What effect would a sunspot have on the surface of Venus, if any? Also, are there any planets that would have a good view of a moon/planet with visible raised terrains?

Hello forum members! I read an article the other day concerning a cosmic event that took place 260 million light years away. The article also suggested that this particular event took place 260 million years ago. Even though I understand the concept that, for example, the light of the sun that we see right now is from ~8 minutes ago (given that the sun is 8 light minutes away from the earth), I felt that the article was not taking into consideration that the universe is expanding; and that the event may have occurred later, but only reached us now, given the compounding effect of the universe's expansion on the distance of that body from the earth. Would anyon…

Hi, This is my google science project. What do you think ? LANDING SYSTEM IN ORDER FOR SPACECRAFT TO LAND ON ASTEROID video: https://www.youtube.com/watch?v=lN3P7enDKuk

I wonder if there are folks on here who might be as interested in the planetoid ceres as I am. I've read that it is hollow, filled with ice, and contains more water than earth. if you are interested in it, then maybe you could help me with a few questions, such as if the water is readily usable, or perhaps the isotopic ratio is too different than that of earth's water. anyway hope somebody out there knows

The Norfolk Island effect was discovered in 1945 when scientists found that at dawn and dust disturbances on the suns surface could interfere with radio/radar signals. So the fact that there is a magnetic link between the sun and planet was demonstrated and established. Now this link is permanent for as the earth rotates then the link advances around the world until in 24 hours it comes back to start again.

Classic physics consider that like charges will always repel each other; yet in the nucleus of molecules they are forced together short range by the Casimir effect. Is this at variance with the standard model??

Why would there be motion in a zero-energy universe?

The Coriolis effect is a new physics explanation of earths rotation . If the flight route distance is 11,000km and aircraft speed is 880 kph in classical physics terms it should take 12.5 hours each way which is confirmed for north/south routes. But due to Coriolis 3D rotation effect the east/west routes in fact takes only 12 hours from London to Malaysia but the return flight from Malaysia to London takes 13 hours as witnessed in flight schedules. To save fuel; fly east into the sunrise. Happy Whitsun landings

This is a remarkable image of Hyperion. http://phys.org/news/2015-04-image-saturn-sponge-like-moon-hyperion.html There doesn't seem to be too much else on YT but could you get a better image than this?

Hey guys, I have read and heard a lot about astronomy but I recently realised there's something about the basics I don't quite understand. For us to be seeing galaxies that formed in a comparatively short time after the big bang, how did we get so far away? Would we not have had to travel at near light speeds so that the light from these galaxies now has to catch us up as it were? In fact, would we not have had to travel faster than the speed of light, otherwise the light would have gone past us as the universe expanded? As you can see I'm confused, any help?

Neutron stars have been described as the most powerful bar magnets in the known universe. This being so, is it possible for the magnetic fields of such compact objects to take precedence even over their gravity fields? An example: would a small object captured by a given neutron star wind up impacting upon one or other of its magnetic poles, rather than gravity pulling it down to impact anywhere else on the star's surface/photosphere? Many thanks.

Would it be possible to represent force vectors at the event horizon of a black hole ? Whirlpool type / Waterfall type / Pyramidal type etc. Is there some discrete force field distortion that occurs at the event horizon ? Or is it an abstraction ?