Astronomy and Cosmology

In a discussion that wandered into asteroid mining possibilities I wondered what is known with confidence about the mineral resources within asteroids. Reconciling the estimates thrown around with the admitted large uncertainty about the quality of mineral ores within asteroids seems to be essential to estimating the economic viability of any attempts to exploit them. Clarity about what form the desired materials take rather than simple estimates of concentrations and total quantities is needed; a pure elemental metal, even at low concentrations may have good potential for mining - relatively simple techniques can separate and concentrate them - whereas higher concentrati…

I'm not sure if I already posted this if so i apologize. Can this star be explained? https://en.wikipedia.org/wiki/Przybylski%27s_Star

I am working on a sci-fi book revolving around an impossible human ability (think "the force") and would like to create an as-plausible-as-possible explanation for it. Godzilla can't actually exist, but still we have a background story involving nuclear bombs and radiation. Hopefully this will be a fun way for you to flex your scientific knowledge, as there isn't necessarily a single correct answer, as long as the end result is a good solid detailed way of getting to the situation in my story's plot. The easiest way to ask what I need to know is probably to outline my skeleton story with some variables (X, Y, Z, etc.) that I would want the more scientifically in-the…

If energy cannot be created, then how was the sun, Earth's main source of energy, formed during the Big Bang?

Delta Aquarids are at peak tonight - if cloud clears look after moon has set http://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide#delta-aquarids

Hi all, some have proposed that we give up trying to terraform Venus because of its terrible atmosphere, and instead try chucking tens of thousands of giant asteroids and Kuiper belt objects at it not to speed it up to an Earth day, but to tidally lock it. The hope is that the bright side would be a great place for solar power, the twilight zone in the middle would be a great place to build domes and habitats to mine all the Venusian mineral wealth, and the dark side would be where all that horrible CO2 and sulfur rained down. The problem is, we don't seem to have agreement on whether or not it would get cold enough back there to freeze CO2. I'm no physicist but it appe…

Hello, So you saw the question. There are some articles that say the energy is must be 0 because the mass of matter is equal to antimatter. But also there is an article by NASA says estimated mass-energy of the universe is 4x1069 . Which one is true? I found the NASA file by a video but not itself. Article on 2:54. There is a link on video connects to here(https://imagine.gsfc.nasa.gov/ask_astro/index.html). I searched on site but couldn't find it.

Przybylski's Star Appears to have to have short lived radioactive elements in it's spectral lines. no reasonable source of these elements is known. As well as short lived elements heavier than uranium and thorium, plutonium is also present. https://en.wikipedia.org/wiki/Przybylski%27s_Star How could such short lived elements be present in this star?

Hello everyone, I always thought it is because of centrifugal force because it makes sense to me. There is gravity pulling and centrifugal force that pushing the planet out and it having an orbit. But someone told me that planets aren't flying out because of dark matter and stuff. Can someone light me up? Also sorry for the bad English.

Out stargazing with the naked eye,if I focus on a particular star,I can see it pretty clearly but if I shift my focus slightly to the side of that star it appears to be brighter and even more focused than before. Is this effect explainable using GR or could it be an aberration of my eyesight?

A "cosmic cloud" falls from infinite space. Then, in the crust of the planet, as in the depths of the primitive oceans, could be observed the existence of a viscous element that covered the whole Earth. With this gelatinous mass, protoplasm was born. This matter, amorphous and viscous, with its condensation gave origin to the birth of the nucleus. The earliest inhabitants of Earth are albuminoid cells, amoebae, and all unicellular organisms that have multiplied in the warm waters of the oceans. These beings only reveal a sense: of touch, which gave rise to all others. Source: url deleted

I once crossed swords with a person who was obviously a "professional" of sorts [at least he seemed competent in maths] when I made a comment to another that gravity makes more gravity. This is due to the property of nonlinearity of spacetime/gravity. I supported my claim with a link to the "Einstein online"site which at this time appears to be down. His "reputation" though was eventually tarnished with his rather grandiose claim that he had disproved GR and later the recently three GW discoveries did not further validate GR. Can someone give a more complete reasoning as to the question of gravity making more gravity, and the property of nonlinearity?. On another…

I found the following article and paper............... https://phys.org/news/2017-06-galaxies-violent.html An international team of researchers has shown that the hot diffuse gas that fills the space between the galaxies has the same concentration of iron in all galaxy clusters that were studied in sufficient detail by the Japanese Suzaku satellite. It seems that most of the iron inside the intergalactic gas arose long before the first clusters of galaxies were formed. The results will be presented this Friday at the annual meeting of the European Astronomical Society, EWASS2017, in Prague, Czech Republic by Norbert Werner, leader of the MTA-Eötvös University Lend…

https://phys.org/news/2017-07-team-astronauts-space.html Scientists at The Australian National University (ANU) have designed a new nano material that can reflect or transmit light on demand with temperature control, opening the door to technology that protects astronauts in space from harmful radiation. Lead researcher Dr Mohsen Rahmani from ANU said the material was so thin that hundreds of layers could fit on the tip of a needle and could be applied to any surface, including spacesuits. "Our invention has a lot of potential applications, such as protecting astronauts or satellites with an ultra-thin film that can be adjusted to reflect various dangerous ult…

I wrote a program to simulate the Tiangong-1 reentry. To better understand how its orbit is changing, I created the attached graphs using 62 TLEs. For each TLE, I calculate the satellite's position, speed and eccentricity by mean of the SGP4 propagator. I collect those values for 5 orbits starting from the TLE epoch with a step of 0.5 s. The "ecc min" and "spd min" behavior seem strange to me in the left half. Is there any chance that the engines (main or RCS) was accidentally fired (I mean a malfunction)?

Can we see stars in all directions at 13 billion light years?

If it is theorized that the Universe is infinite and matter exists throughout all of it. Doesn't that mean that there is more matter that we cannot see than matter that we can? If this is true, than there should be more gravity pulling outward from every direction, and therefore fueling the expansion.

So the Solar System has a few mysteries contained in its creation that seem to defy modern physics. The potential that our Solar System may in fact be the remains of a stellar merger may help to resolve many of the inconsistencies as opposed to the majority of observation throughout the galaxy. If the system had originally began as a binary, the gas giants that would’ve formed may have been accelerated into an increasing orbit as the resonant tug from the orbiting suns transferred their momentum. At that point, if one of the suns had inflated into a red giant, fusing helium into carbon and oxygen, and then collapsing into a white dwarf, leaving an inner planet…

If I have a very accurate scale and place a weight of exactly 1 Kg at a certain time, leaving it there and observing it over a prolonged period of time. Will there be any variations caused by the movement of the objects in our Solar system?

It is accepted that stars form in dense clusters which break up as the individual stars move away. Why do clusters of stars not gravitationally collapse further into one huge star? What causes these star clusters to break up?

I was watching a video about Black holes, firewalls & EP=EPR with Leonard susskind, he mentions how in theory you could make two macroscopic objects that are entangled, by continually shooting off entangled pairs in opposite directions & then compressing the two masses of pairs. Or collecting up the emitted hawking radiation the original black hole has emitted & squeezing it down to a black hole so the original & new black hole are now entangled. Well that is what it sounded like to me. Is this kind of thing even possible? Can two large macroscopic objects be entangled? With everything I have read on entanglement it seems to apply only to small sy…

I came across the following article.....comments appreciated....... https://phys.org/news/2017-06-universe-big.html No Universe without Big Bang June 15, 2017 According to Einstein's theory of relativity, the curvature of spacetime was infinite at the big bang. In fact, at this point all mathematical tools fail, and the theory breaks down. However, there remained the notion that perhaps the beginning of the universe could be treated in a simpler manner, and that the infinities of the big bang might be avoided. This has indeed been the hope expressed since the 1980s by the well-known cosmologists James Hartle and Stephen Hawking with their "no-boundary proposal", and…

I have what I think is a new idea about the CMB (I haven't turned up anything similar so far). I'd be very grateful if you could look at it and let me know what you think: "Is the CMB a Reflection of the Universe Before the Big Bang?" link removed Many thanks Kev

If neutron star contains mostly neutrons, its magnetic field is in the range of 10^4 to 10^11 Tesla, but our sun containing a large amount of plasma have only 150 mT. How is it possible?

What is the state of Black hole? Is it solid or any other 5th state?