Astronomy and Cosmology

Hello! Could someone tell me in what ways does the moon affect us? I am particularly interested in direct effects on our body or psyche, but also effects on our planet might be interesting. Thank to you all!!

so im quite curious (not a physics or astronomy student) and even after some research on the internet i am still slightly confused. can anyone give some brief explanations of facts that support the big rip?

Hello, I am going to start to create my own telescope and was wondering if I could get away with having a thin primary telescope mirror. Please tell me if this will ruin my telescope. I was thinking about making the telescope out of a parabolic mirror that is 35" by 1/2" thick. I have also heared that by exposing a thin parabolic mirror to different temperatures it changes its shape causing it to move its focal point, is that true?

Hello, I am 13 year old trying to better understand other thoughts and opinions in opposition/ difficulties with this experiment.

Popular science literature often raises questions about a “boundary condition” at the Big Bang, which necessitated a low entropy scenario. In the FLRW model the Universe in its first instant is miniscule (a single quantum, as Lemaître described it). This “Primordial Atom” contained all the matter and energy of the Universe, which completely filled the tiny space it occupied. In that first “quantum” matter/energy occupied all the available space; there was no room for “manoeuvre”; entropy could not have started evolving until more space became available (?). What does it mean to equate this to a low entropy boundary condition? Surely, in that first instant, entro…

Is there a list anywhere of the largest galaxies in the Virgo supercluster? Wikipedia doesn't really seem to have what I'm looking for.

I am interested in the history of astronomy, most particularly how did astronomers over the last few hundred years come up with estimates of the mass of all the solar system bodies, i.e. the Earth, the moon, the Sun, the planets and their moons? And also all the distances and orbital parameters. It seems to me that they would have had to know at least some of those parameters in order to calculate the rest. I am interested in the whole process that they went through over the the last few centuries. Do you know of any books or websites about this?

Every time it think it have a decent handle (for a layman) on cosmic expansion I start reading and realize I know nothing. Yehuda Hoffman at the Hebrew University in Jerusalem claims to have discovered a great void that is actually pushing the Milky Way and others towards the Shapley Supercluster. Scientists have known for sometime that Shapley is pulling us and everything is in our neighborhood but it's gravity is not enough to explain the high velocity of our galaxy. The part i don't understand is how it is pushing. The article says because of the dearth of mass in the void expansion is moving at a faster rate. So if guess expansion in that area is moving the surrou…

The micro-universe is comprised only of waves of energy...different frequencies...and charges...please contribute to this thread... I can find nothing else that contributes to out understanding of the atom...

All right my first question and first thread all in one. I'm excited and hope you are too. After doing a search I see that no exoplanet moons have been confirmed but my question is could the mass of some planets be overestimated because it has one or more large moons. I assume if our earth is being detected by alien astronomers by the same techniques we use the extra mass of our moon wouldn't really matter all that much. But is it possible for two earth sized bodies to have a stable and close orbit or an earth sized body with several large moons. Could this account for at least some of the superearths?

I’v I've been looking for “hitch-hiker” level information about Horava gravity. Most of what I have found is way beyond my maths, but I’m wondering about the reasoning of this point from Anathaswamy. (NS. 07.08.10.). “Investigating the properties of graphene was a significant factor in the development of Horava’s ideas.”…..”An odd feature of this material is that its electrons move about on its surface”. their movements are described using QM, and, “…because their motion is at only a small fraction of the speed of light, relativistic effects can be ignored”. When it is cooled to temperatures close to 0K. “… the motions of its electrons speed up to the extent…

I'm really not getting Kepler's laws, so I have four different questions about how binary star systems work. First, say there is a binary system that consists of two white dwarfs in circular orbits with an orbital period of 60 days. Is it even possible yo find the maximum distance between the two white dwarfs? Next, If one of the white dwarfs is twice as massive as the other, what is the approximate maximum orbital radius of the smaller star? Next, If the angular separation of the two white dwarfs is measured (I don't know how) to be 0.013 arcseconds(the system is viewed face-on). If the stars were estimated to have equal masses of 0.8 MSun each, approxi…

If we assume for a minute that there is something wrong with the current thinking that the expansion of the universe is accelerating and assume that it is in fact still decelerating and will eventually stop and then begin the Big Crunch, the Big Bang in reverse, at the end of the Big Crunch could some fundamental instability be reached that would trigger another Big Bang? If this were the case then "start of Big Bang to end of Big Crunch" could represent just one cycle in an infinite series of such cycles, such that the universe, in one form or another, has always existed and will always exist? Meaning that there was no beginning and there will be no end, and time is in…

Could the matter that is sucked into the black hole be crushed into an infinitely dense ball, similar to the one which started our universe. I have other ideas about this thought, but wanted to see what other people have to say about it.

can someone help me out to create one?

This question/discussion proposal was inspired by the discussion in this thread, but is not directly on topic there. http://www.scienceforums.net/topic/102170-an-issue-i-have-with-gr-physics-versus-newtonian-physics/page-2#entry966276 It appears to me that accepting universal expansion has-implications-for/constrains acceptable coordinate systems. Consider static points on the classic 2D manifold surface of a balloon. As manifold expansion occurs: 1) For xyz coordinate systems all of x and y and z will be different before and after expansion. 2) For cylindrical coordinate systems the angle will remain unchanged, but r and z will be different. 3…

I wont claim to be well versed by any standard on this subject so please be nice. One detail I am not sure of about the Big Bang is how much the big bang created and how big researchers are predicting how large the initial amount of mass could have been to accomodate that size of reaction. Did the big bang create just the Milky Way galaxy and other Big Bangs created other galaxies or was it just one giant Big Bang and, over time, the other galaxies separated and gained substantial distance from eachother? Could someone please clarify this/these details for me? I cant seem to find the answers myself no matter how hard I search.

Where are we in the universe? Are we in the middle of the cosmic microwave background?

Didn't a resent study of more super nova detail that the universe is not actually accelerating ..but is still expanding at a consistent rate?

I am trying to paste in a download from Word for some time. My Eureka moment came from inverting one of sciences assumptions which provided the missing definition of Gravity which led toward what Black-holes probably are, followed by proposing Time before the Big Bang and how this event managed to spew out enough matter to furnish the universe in which we have evolved. The proposal also disposes that creation was not the invention of a superior intelligence but the logical result of a force field operating within infinity. If I was able to publish the paste from Word to show the entire argument I would very much like the opinion of my peers. If my basic 'inversion' is wro…

I note this site is still refusing a Paste from Word. To read this extraordinary post which proposes the missing definition of gravity and where the Big-Bang got all its material to furnish the universe in which we have evolved, go to (removed), the UK equivalent of Science Forum. conway2 .

Hello! "Astronomers unveil most detailed map of the Milky Way to date" http://sci.esa.int/star_mapper/ https://www.theguardian.com/science/2016/sep/14/astronomers-milky-way Best Regards!

The measured value of the Hubble constant depends on the observations : Planck Mission gives a value near 68 km/s/Mpc and Ries (HST) gives a value of 73 km/s/Mpc. Does the standard model ask a constant value for all the periods ?

In observational comsology how can we sure that the oberved objects (galaxies) are all distinct and not (for many ?) a different image of the same source via the gravitational lensing effect ? Thanks. ES111