Astronomy and Cosmology

Hi Everyone! I’ve recently Jokin this forum and i wanted to ask a question. Yesterday, i Saw a video in which it appeared Neil de grasse Tyson, and he explanes that tides where because of not only the Moon but the sun too. So, i was wondering if someone in the comments can simplify me the explanation of this event.

Hi. I have put in the internet search engine the following: longest wavelength electromagnetic waves in space The following appeared in the list of the findings: https://hypertextbook.com/facts/2001/RachelShapiro.shtml Electromagnetic waves as long as the distances between astronomical objects. Do those waves fulfill any known function?

Science says (I think) we can make artificial gravity in space using a centrifugal force on the inside of a rotating circular structure. If so, anyone know what maths and physics I need to calculate speed of rotation for a given radius of a circular spaceship? Cheerz GIAN

Hello, I see video’s on the mechanism of the solar system, about orbits of the planets around the Sun. In such video’s they say there is a gravity between the planets and the Sun to explain those orbits, but how important is the rotation of the Sun? Maybe the rotation of the Sun is of much more influence than Newton and Einstein have described?

In addition, what would happen if you were to put your hand inside a black hole (1) the size of a human hand (2) the size of a speck of dust Wait answer this question, second to my first question, how powerful would a black hole the size of an atom be?

https://phys.org/news/2018-08-ice-moon-poles.html Ice confirmed at the Moon's poles August 21, 2018, Jet Propulsion Laboratory: In the darkest and coldest parts of its polar regions, a team of scientists has directly observed definitive evidence of water ice on the Moon's surface. These ice deposits are patchily distributed and could possibly be ancient. At the southern pole, most of the ice is concentrated at lunar craters, while the northern pole's ice is more widely, but sparsely spread. A team of scientists, led by Shuai Li of the University of Hawaii and Brown University and including Richard Elphic from NASA's Ames Research Center in Californ…

Stretching within itself. How do we know the universe is expanding? What is it even expanding into?

https://phys.org/news/2018-08-hubble-picture-evolving-universe.html Astronomers using the ultraviolet vision of NASA's Hubble Space Telescope have captured one of the largest panoramic views of the fire and fury of star birth in the distant universe. The field features approximately 15,000 galaxies, about 12,000 of which are forming stars. Hubble's ultraviolet vision opens a new window on the evolving universe, tracking the birth of stars over the last 11 billion years back to the cosmos' busiest star-forming period, which happened about 3 billion years after the big bang. Read more at: https://phys.org/news/2018-08-hubble-picture-evolving-universe.html#jCp

https://phys.org/news/2018-08-oort-clouds-stars-visible-cosmic.html Oort clouds around other stars should be visible in the cosmic microwave background August 16, 2018 by Matt Williams, Universe Today For decades, scientists have theorized that beyond the edge of the solar system, at a distance of up to 50,000 AU (0.79 ly) from the sun, there lies a massive cloud of icy planetesimals known as the Oort Cloud. Named in honor of Dutch astronomer Jan Oort, this cloud is believed to be where long-term comets originate from. However, to date, no direct evidence has been provided to confirm the Oort Cloud's existence. Read more at: https://phys.org/ne…

Have I understood this correctly? Is it really proposed that this may have happened with with a symmetric or asymmetric balance of negative and positive "energy? Any evidence or proposed experiments along those lines? Quantum fluctuations don't normally "run away with themselves do They?

I understand the c fills this role but I would like to ask if that is a purely experimental finding or if there is an underpinning of a theory to it. The argument I think goes like this. There has to be a maximum speed of information transfer ,otherwise things would occur at the same time. Now we do have a maximum speed that has been observed and it is the speed of any massless object in a vacuum. Connect the dots and they are the same speed... Any more to it than that? Could it actually be higher if we came across objects that actually traveled faster than c in a vacuum? By the way ,if dolphins communicate b…

https://phys.org/news/2018-08-quest-source-black-hole-dark.html Quest for source of black hole dark matter August 14, 2018 by Anne M Stark, Lawrence Livermore National Laboratory Like a game of "hide and seek," Lawrence Livermore astrophysicists know that there are black holes hiding in the Milky Way, just not where. "If they find them toward the galactic bulge (a tightly packed group of stars) and the Magellanic Clouds, then black holes as massive as 10,000 times the mass of the sun might make up dark matter. If they are only toward the galactic bulge then they are probably just from a few dead stars." Read more at: https://phys.org/news/2018…

Is the Universe infinite or just really, really big?

Do supernovae scatter their heavy elements (after iron-56) far away in space, which, as a result of this event, could be absorbed by exoplanets in another galaxy? And why does Earth seem to have so many heavy elements? Shouldn't there be more heavy elements on Venus and Mercury instead?

The primary evidence for Dark Matter is the observation that many distant galaxies have stars rotating at pretty much the same velocity. Perhaps the structure of the galaxies can explain the phenomena. A galaxy with most of the matter near the center of the galaxy would have the orbiting outer stars with a lower velocity than the inner stars. However, with a disc shaped galaxy with evenly spaced stars, the outer stars would have a higher velocity than the inner stars. The reason is that the orbit of a star is not affected by evenly spaced stars further from the center of the galaxy. The calculation of the relative velocities of stars in the di…

Is a soap bubble a valid analogy for the expansion of space? Most science-related discussions at home currently starts with questions from the kids meaning I need to use simple and concrete examples*. I find the the analogy with pennies on a balloon** useful when thinking about basic aspects of big bang and expansion of space. How about a modified balloon analogy with ”observers” that are more part of the analogy than us outside watching the balloon growing in 3D space? The goal is to have an equally valid analogy and replace the balloon surface with something where it, hopefully, would be easier to imagine an observer of the expansion. Imagine some very small…

The eclipse will be visible in parts of Australia, Asia, Africa, Europe and South America. It will start where I am around 20:30 and reach its peak at 21:30. It should be especially nice because Mars will be very clearly visible as a the brightest object among the stars and will be visible in red color close to the eclipsed moon. https://www.timeanddate.com/eclipse/lunar/2018-july-27

Is dark energy the root of dark matter I am not a scientist of any type but I am captivated by the fields and my mind is always trying to think of the unknowns of science from Space-time to Quantum Physics and there are a number of things that bother me so I have decided to reach out today with one idea I have however far fetched it might be and see what kind of responses I get in hopes to broaden my understanding of what is known and possibly not understood. I for one have an issue with the big bang theory and have a hard time believing that billions of galaxies, stars etc. came from an atom sized explosion just to clear that up from the start although I am agnostic…

What cosmological information is expected/obtained from gravitational wave astronomy?

First of all, this is my first post, sorry if I did something wrong. So according to the Einstein`s theory of gravity, gravity is caused by a distortion or curve in space-time, and the curve becomes the new route for the object, because its the straightest route. Does the velocity of the object change? And if it does, what makes it accelerate? Lets say that the things that have mass would be bigger in space-time. More mass, more space-time covered. In our measurements, the speed of the object would increase, because it covered more distance in the same time. In space-time however it would be the distance that increased. And what if light…

https://phys.org/news/2018-07-gravitational-reveal-fast-universe.html Since it first exploded into existence 13.8 billion years ago, the universe has been expanding, dragging along with it hundreds of billions of galaxies and stars, much like raisins in a rapidly rising dough. Astronomers have pointed telescopes to certain stars and other cosmic sources to measure their distance from Earth and how fast they are moving away from us—two parameters that are essential to estimating the Hubble constant, a unit of measurement that describes the rate at which the universe is expanding. But to date, the most precise efforts have landed on very different values of t…

For the electric forces, opposite charges attract, like charges repel. For magnetic forces opposite poles attract and like charges repel. But for gravitational forces, matter attracts matter. What about the gravitational forces between matter and antimatter? What about the gravitational forces between antimatter and antimatter? Does antimatter gravitationally attract other antimatter? Does matter gravitationally attract or repel antimatter? We believe that matter and antimatter pairs will destroy each other on contact. We believe that matter and antimatter pairs appear to be randomly created. Let’s assume that in the Big Bang equal amounts of mat…

Recently I saw a piece on Fox News about the Fermi Paradox on the Greg Gutfeld show. That caught my attention because they usually discuss politics and because astronomy and cosmology are my favorite areas of science. Greg suggested that there is probably no intelligent alien civilizations out there because if there was they would have become obvious to us. Here is what Wiki has to say about the Fermi Paradox: "The Fermi paradox, or Fermi's paradox, named after physicist Enrico Fermi, is the apparent contradiction between the lack of evidence and high probability estimates[1] for the existence of extraterrestrial civilizations.[2] The basic points of the argument,…

Stop thinking UFO, I'm looking for more plausible, or perhaps credible answers. I am a boater and am currently practicing using a sextant. I've been observing the night sky far more often over the last two months. On several occasions I see points of light move across the sky slowly. They do not exhibit parallax, the relationship between the apparent altitude, distance and velocity. (for example, The difference between the moon's apparent altitude in the early evening and early morning is appears greater than from an observer located on the surface of the earth because the observer's location moved.) Remember, I'm practicing the use of my sextant. So I can se…

My questions here were prompted by the following article..... https://futurism.com/rethinking-space-time-nature/ extract: Question: How valid is the first quote? With regards to the second quote, here is the paper...... https://arxiv.org/pdf/1712.02803.pdf Bulk Entanglement Gravity without a Boundary: Towards Finding Einstein’s Equation in Hilbert Space: Abstract We consider the emergence from quantum entanglement of spacetime geometry in a bulk region. For certain classes of quantum states in an appropriately factorized Hilbert space, a spatial geometry can be defined by associating areas along codimension-one surfac…