Astronomy and Cosmology

Can someone show the math that describes light being trapped at the event horizon? Perhaps link? Googling this does not provide good mathematical descriptions.

Can this exist?I have been told that it does but I cannot seem to find any old posts lying around the internet that support this idea. Anyone here want to have a go at the question (it is understood that there is no centre ,I am asking whether there is a centre of mass ,although it could not be used as special Frame of Reference)

I have been trying to find an analogy to help me understand the expansion of the universe. It’s been almost s year. Track an air bubble from below the surface of the sea. As it rises it expands and accelerates. For known reasons. So as a large helium weather type balloon. No added energy required.

Or is this simply evidence that maybe the standard particle model needs reevaluating? https://www.livescience.com/62721-sterile-neutrino-detected-fermilab.html A Major Physics Experiment Just Detected a Particle That Shouldn't Exist: Scientists have produced the firmest evidence yet of so-called sterile neutrinos, mysterious particles that pass through matter without interacting with it at all. The first hints these elusive particles turned up decades ago. But after years of dedicated searches, scientists have been unable to find any other evidence for them, with many experiments contradicting those old results. These new results now leave sci…

OK, I have my 59th Old Boys reunion coming up shortly.....a right royal piss up it looks like being. As the only one interested in cosmology to the extent that I obviously am, three of the more interested old farts have asked me to properly describe BH's. So here it is..........Any errors, alterations and/or corrections recommended by our on line professionals is welcome? BH's of sorts, were hypothesised to exist in 1789 by John Michell. This Newtonian variety were called "Dark Stars" and did have a surface just below where the density of the relevant matter, had an escape velocity equal to "c". His work was not taken seriously and was pigeon holed until many year…

What in the estimated position of Pioneer space crafts, are they in the Kepler Belt ?

https://phys.org/news/2018-06-speculative-wormhole-echoes-revolutionize-astrophysics.html Speculative wormhole echoes could revolutionize astrophysics June 12, 2018, Plataforma SINC The scientific collaborations LIGO and Virgo have detected gravitational waves from the fusion of two black holes, inaugurating a new era in the study of the cosmos. But what if those ripples of space-time were not produced by black holes, but by other exotic objects? A team of European physicists suggest an alternative—wormholes that can be traversed to appear in another universe. Scientists have deduced the existence of black holes from a multitude of experiments, the…

This article today in https://phys.org/news/2018-06-dark-inflation-gravitational-window-moments.html Dark inflation opens up a gravitational window on the first moments after the Big Bang: Dark matter and dark energy may have driven inflation, the exponential expansion of the universe moments after the Big Bang. A new cosmological model proposed by physicists at the University of Warsaw, which accounts for dark inflation, is the first to outline a precise chronology of the main events during the early history of our universe. The model makes a spectacular prediction—that it should be possible to detect gravitational waves formed just fractions of a second after …

Ever since I heard that our solar system is hypothesized to be surrounded by a massive spherical cloud of trillions of comets extending a good way to our nearest star (if that was exaggerated, let me know), I've been wondering whether or not this Oort Cloud may provide us 'some' protection from gamma ray bursts? My reasoning is simply that the beams of gamma ray bursts are typically, if I'm not mistaken, relatively 'narrow' (using the term 'narrow' loosely, of course), and thus might have 'some' difficulty making it through such a cloud without losing some of its energy striking the comets of the cloud. In other words, could the Oort Cloud help to, for lack of a bette…

Hello! I would like to know, when did humans realize that there are another galaxies? I have heard that it was when Hubble discovered, that Andromeda's nebula is The Andromeda Galaxy, but as I know, Hubble was launched in 1990 and I can't believe that we thought, that our galaxy is alone till that date (1990+).

I often here how an objects radiation would redshift and then fade when entering a black hole, but this is from an outside perspective. When I hear about the perspective of the object, they say you would “spaghetify” as you approached due to tidal forces of gravity. This is the part that confuses me. If space time is stretched, and the object is stretched with it, is it possible that the object would not be able to tell it was rapidly descending through time shells? Wouldn’t the object continue to expierience free fall? From the outside perspective it is accelerating, but from the object’s perspective it is stationary to the things immediately around it. A tape meas…

I took this photo of my daughter this morning and was wondering what planet that is. My husband says Venus. Obviously i know nothing about astronomy, lol. I thought it was just a glare but I took like 10 pics of her and its in all the pics in the same spot so I figured it was a planet. Thank you! Woops I forgot to mention that we live in Oklahoma City, Oklahoma and the picture was taken around 8:30am

Over the last couple of years or so, a cosmological discovery, perhaps the most momentous of the century, has been unveiled.Detectors, have fulfilled one of Einstein's GR greatest predictions...that of gravitational waves from coalescing binary BH pairs and also Neutron star pairs: Besides further validating GR, it of course has validated any doubts about the existence of BH's. Here is an interesting article...... https://phys.org/news/2018-05-dozens-binaries-milky-globular-clusters.html The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A string of detecti…

The atmospheric density as well as pressure at the surface of Titan is like being in about 15-20 feet of water here on Earth and surface gravity about 0.1G. If so, does anyone know if it would be possible with flippers and the right equipment to 'swim' through the atmosphere at the surface of Titan? ta

I have a small question that has been teasing me of late. If the universe is expanding, and total energy can neither be created nor destroyed, and every inch of the universe is a field (eg magnetic field), then why doesn't field strength weaken as the universe expands?

Brief Conceptual Introduction: I think of the multiverse as a Rubik's Cube comprised of an infinite number of infinitely large cubes -- all connected, but also distinctly separate. My understanding of the world embraces consciousness as a universal characteristic, not a byproduct of chance that is unique to our world. It builds upon the concepts of balance, persistence, and relativity, but not symmetry or equality in the traditional context. All universes are boundless but not infinite, in that they are inescapable, but limited in scope by time. That is to say that a photograph of the entire universe would allow for measurement, but subsequent observation would…

When watching documentaries, it happens quite often that some kind of scientist says that a planet might have captured one of its moon. I have never understood how that should be the case. When a moon orbits a planet, we can predict where it will be in future according to Newton's laws of gravity. The result will be that it is the same orbit as it is currently in. Likewise we can let time “run backwards” and calculate where the moon must have been in the past. We get that it must have been in the same orbit as it is currently in. As we do not see moons suddenly leave their orbits and fly into space, I would not expect them to suddenly fly in from space and start orb…

Hubble's Law = the velocities of recession of galaxies are proportional to their distances from us. Do we see galaxies following Hubble's law (distant galaxies moving faster and faster away from us) ot do we observe the (light of the) past, where galaxies further away are closer together? (because the further we look, the further we look in the past). Are far away galaxies closer together (the further we look in the past, the smaller the expansion of the universe back then) or are far away galaxies been observed further away (following Hubble's law)? Thank you for answering these questions.

Hubble's Law = the velocities of recession of galaxies are proportional to their distances from us. Imagine that we observe a galaxy far away from us, moving with very high velocies away from us. We know that the light of the star in the front of that galaxy reaches our eyes 10.000 years earlier then the light of the stars in the back. (we only can see the past and the further we look, the further we look into the past). Why is it that we see this whole galaxy moving away from us, while the observed stars in the front are from a period of time which is (for example) 10.000 years earlier then the period of time of the observed stars in the back of that gal…

So I took a picture of the Moon and sun at the same time. But the moon was not where you would normally see it in pictures. This was taken in New York City at a partial eclipse. You can see the eclipse still. Is this a super rare phenomenon? Is this because it was taken at an angle? I am stumped. I am not too good at science, I am young so I don't really know. The blue surrounding it was some stupid idea to put my bad sunglasses over my phone camera lens to protect it. In my mind I was like. It is something. And luckily my phone survived. Is it even the moon? I believe it is. I cropped it and have the full 16:9 photo too. This was the solar eclipse in August 2017

I have a question on these issues I have never seen addressed as a whole . We believe in the probability of dark matter because the universe hasnt flown apart, but there isnt enough visible mass to account for the necessary gravity to prevent this. We believe in the probability of dark energy because something is driving the universe apart at an increasing rate, yet we cannot see this energy. These seem almost like contradictory statements. We believe in DM because the universe HASNT flown apart, yet we believe in DE because the universe IS flying apart and eventually every galaxy will be too remote to see any other galaxy in the universe. What is the solutio…

A pretty cool simulation of everything in orbit around the Earth: http://stuffin.space/?intldes=1983-001A And an article about it here: https://www.universetoday.com/138981/this-is-the-coolest-everything-thats-orbiting-the-earth-right-now/

Would I be right in calculating that Eddington's value for the grazing deflection of light past the Sun of 1.6 seconds of arc implies a value of around 9.6 x 1017 metres for the curvature of spacetime in the vicinity of the Sun?

https://phys.org/news/2018-04-astronomers-witness-galaxy-megamerger.html Peering deep into space—an astounding 90 percent of the way across the observable universe—astronomers have witnessed the beginnings of a gargantuan cosmic pileup, the impending collision of 14 young, starbursting galaxies. This ancient megamerger is destined to evolve into one of the most massive structures in the known universe: a cluster of galaxies, gravitationally bound by dark matter and swimming in a sea of hot, ionized gas. Read more at: https://phys.org/news/2018-04-astronomers-witness-galaxy-megamerger.html#jCp The results are published in the journal Nature. <&lt…