Astronomy and Cosmology

https://phys.org/news/2018-02-laser-ranged-satellite-accurately-earth-tidal.html Laser-ranged satellite measurement now accurately reflects Earth's tidal perturbations Tides on Earth have a far-reaching influence, including disturbing satellites' measurements by affecting their motion. This disturbance can be studied using a model for the gravitational potential of the Earth, taking into account the fact that Earth's shape is not spherical. The LAser RElativity Satellite (LARES), is the best ever relevant test particle to move in the Earth's gravitational field. In a new study published in EPJ Plus, LARES proves its efficiency for high-precision probing of Gener…

https://phys.org/news/2018-02-ultramassive-black-holes-far-off-galaxies.html Thanks to data collected by NASA's Chandra X-ray telescope on galaxies up to 3.5 billion light years away from Earth, an international team of astrophysicists has detected what are likely to be the most massive black holes ever discovered in the universe. The team's calculations showed that these ultramassive black holes are growing faster than the stars in their respective galaxies. Read more at: https://phys.org/news/2018-02-ultramassive-black-holes-far-off-galaxies.html#jCp extract: "The results showed that the masses of ultramassive black holes are roughly 10 times gr…

TIME By John K Daly Why is the future not knowable in the way the past is knowable? Why does time seem to flow in one direction? Why is there an arrow of time? What is time? These seem like difficult questions, but they are not. There is a simple path to an accurate understanding of their answers. To begin to understand these questions, consider the expansion of an inflating balloon. Its surface is expanding such that if you pick any point on the balloon, every other point on the balloon recedes from the point you picked. If you think about how this works everywhere on the balloon, you realize that what is really happening is that new area is …

Hello, I'm new to the forum. If everything had a source, (like a mother and a child, or the sun and plants) then where did gravity come from?

In school our teacher said that black holes have such a huge gravitational pull that not even the light can escape it.I asked him how since the light has no mass.He said that photons actually do have a mass but only if they are not moving and he showed us Einstein's equasion about mass and velocity: m=mo/(square root)1-V/c .How is that even possible? Sorry about any mistakes and about that square root thing but I'm using my phone and there is no square root on the keyboard

For the last 88 years we have used Subrahmanyan Chandrasekhar's calculations to determine the maximum mass of a white dwarf. As a result of that mass limit a peak brightness was derived and the Standard Candle was born. However, those calculations were made based upon certain assumptions, namely that the white dwarf was not rotating and had no magnetic field. More recent discoveries (specifically SN 2003fg, SN 2006gz, SN 2007if, and SN2009d) have demonstrated that those assumptions made in 1930 may not hold true in some cases. The white dwarf mass prior to SN 2007if's deflagration, for example, was estimated to be 2.4 M☉. In 2013 a paper that was published by U…

Does anyone know what the mass of a gas planet would have to be for it to be stable and fusing deuterium if it was made up of 100% deuterium? Or if such a body was made up of helium 3? I've been trying to use google to get some info on that possibility but evidently no one wants to know but me...

According to the published data the Universe as a result of the Big Bang, expands at an increasing rate, with a speed increase of about 70 (km / s) / Mpc, the same for all observed galaxies, regardless of their distance from the Earth. The radius of the observed Universe was set at about 13.7 billion light years. Based on the above data the age of the Universe was estimated at about 13.7 billion years. From the modeled calculations in the Sagitarius BR program available at the link: https://www.dropbox.com/s/a1cu74xj4ep9iyq/SagitariusBRprogramForCalculationsOfSpeedOfStars.xlsx?dl=0, one can draw contradictory conclusions regarding the age of t…

Is folding space (or wormholes) a good method of space travel; that is if it actually exists or is a theory that people except? I remember on a history channel show about space travel, that there was something called "rosen bridges" or wormholes that were everywhere in einstein's theories. Apparently they're tunnels of folded space making the distance very short. Is this even possible? If so wouldnt it take a long time to actually fold the space anyways because in order to fold it, the two points would still have to travel the same long distance just to get to the position where they are now folded? I know this question probably seems too general of a qu…

I remember watching a NGT documentary on Netflix, and he mentioned something abouto Photons and how the first ones, from the big bang, witnessed the big bang. Or something about how when they are born, until they reach their destination, they see the birth and death of the universe. Would make for some sick go-pro footage i might add. So in theory, if you could fold spacetime and "Beat" the photons in whatever direction they are heading, or just match their pace, you could look back into the universe and witness our universe be born. Kind of like how if you instantly travel 65 million light years away, you could see earth be hit by an asteroid, killi…

What would be the theoretical maximum spin-rate of a small asteroid (25 - 100m diameter?) if it were, for example, composed of a single 'monolithic' chunk of iron? This question arose after reading up on the subject in a Wikipedia article. Listed in it is one such asteroid with a spin-rate of around 30 seconds. Could this be bettered, given the above parameters? Many thanks. https://en.wikipedia.org/wiki/List_of_fast_rotators_(minor_planets)

I haven't been keeping up with progress in discovering exoplanets so was surprised (amazed) by this graph summarising the number and range of sizes found so far, mainly by Kepler. From this article (which is mainly about why Kepler is not going to find much more): https://medium.com/starts-with-a-bang/why-nasas-kepler-mission-is-toast-9f2c484abd01

Okay, so I couldn't understand why the universe is flat after the big bang theory. Because obviously it should be shaped like a ball. So I did good old fashion googling and found that the answer is: "Technically we only know the observable universe is flat." But why is the observable universe flat? I mean, we can see for 46.6 billion lightyears in either direction of the XY coordinates. Why can't we look "up" figuratively, and see for another 46.6 billion lightyears? If we only know the observable universe is flat, wouldn't it be pretty easy to look up and figure out really quickly that it expands just as far up and down as it goes sideway…

Alright, say a rocket was sent towards Mars, at a point it's delay of radio signals was 12 minutes. Every second it sent back a short radio signal signalling the second. So: 1. 2. 3. 4. 5. As it got farther away, I have a question. Would the signals stop reaching earth every second and start having longer and longer periods of time between them? Or what exactly would happen? Would it maintain every second signal, but the signal you're getting was sent 12 minutes ago?

Want to ask next everybody the different stages of the early formation of the moon to now, in my limited knowledge, only know that the moon formed, volcanic eruption, the magma is the moon, now the formation of low-lying lava covered the moon in the sea, and therefore, consult everybody The first question: why is the moon's back moon low Second question: is the moon's highlands caused by the moon's crust movement? Third question: what stage did the moon go from birth to form now Fourth question: is the moon's core empty? My English is not very good, I don't understand where I can understand

Space between non gravitationaly bound objects such as galaxies increases with time. I have read about the consequences of this phenomenon but not so much about the phenomenon itself. It permits objects to recede from one another at speeds higher than c,I think. Is this speed as seen from a third frame of reference or also from that of one of the objects in question? If the latter is true does that imply that these objects are (never were) not connected in the causative sense? Also ,is Inflation similar to Expansion (differing in degree and circumstance as it were) or are they completely different animals?

The Hubble Telescope has shown that in the darkest places of the Univerce there are old Galaxies!!!... So, is the Black Night Sky only an Illusion of our Eyes???... ( IF we had Eyes like the Telescopes would the sky be full of sunlight???...) Thank You...

Constant Space December 30, 2017 "Dark matter" and/or "dark energy", seems that is a next in thinking about the whole "universe". Many very intelligent people who study such things are spending a lot of effort, time, and human energy in trying to find out what is this invisible matter, or force, particle, energy, etc. And, if this invisible thing is discovered, then how does it fit in with the BB theory and other ideas as to how the whole universe and all of its "matter" came into being? I'm not a physicist, but I love to read about cosmology, its physics, and ideas about where everything may come from. There are some who think that this dark matter …

---- Please excuse my ignorance but I’m what you would call a mathematical illiterate. For a while now, I have pondered upon the origin and Big Bang of the Coamic egg and each time I perceive before rapid inflation, a white holes creation. This white hole being dense warped space and time ... Dark Matter was also encapsulated at cosmic origin, and unlike the white hole, sealed by an super symmetric electro magnetism... the fields of dark matter and the white hole converge and repulse each other spawning Dark Energy... Not only is it an expanse of space but the entropy of white hole energy is at scalar 0 while it expands... energy at all scalar 0 in expanding/warp with…

Hello! I'm an amateur researcher. I would like to hear, what can you say about a model, which I've made and which explains the interaction between space weather and circulation of airmasses in the atmosphere. I've tried to base it only on officially approved knowledge, but as I am just an amateur, I would love to hear some professional opinion. Model is based on the laws of magnetohydrodynamics (MHD) and supported by scientific publications. Shortly speaking, orientation of IMF sector determines the direction of current during a process, known as flux transfer event (fte). Flux tubes form along open magnetospheric field lines and create a physical pressure on atmosphere …

https://phys.org/news/2017-12-scientists-solar-giant-star.html Scientists describe how solar system could have formed in bubble around giant star December 22, 2017, University of Chicago Despite the many impressive discoveries humans have made about the universe, scientists are still unsure about the birth story of our solar system. Scientists with the University of Chicago have laid out a comprehensive theory for how our solar system could have formed in the wind-blown bubbles around a giant, long-dead star. Published Dec. 22 in the Astrophysical Journal, the study addresses a nagging cosmic mystery about the abundance of two elements in our solar sys…

Can we stop using the name “Dark Matter” for the name of the unknown force that induces the extra motion of stars around a galaxy or induces the paths of galaxies to follow paths of intergalactic tendrils and instead call it by all we know is true in that there must be a Dark Force that induces those properties in the Universe?

I saw an article on the internet within the past week about a scientific paper that was published on November 22 in the Astrophysical Journal by Swiss astrophysicist André Maeder, raising the question does Dark Matter really exist and proposing an alternative theory to fit the observations, interesting, see: https://www.space.com/39001-dark-matter-doesnt-exist-study-suggests.html?utm_source=sdc-newsletter&utm_medium=email&utm_campaign=20171208-sdc And on the subject of Dark Energy, is it real or is there something fundamentally wrong with the assumptions. What was the exact methodology that the astronomers used to conclude that the expansion of the univ…

I realize that this is probably not the best forum to ask this question, but I thought some of you might know the answer.

The interactive model can be found at: Action Dynamics of the Local Supercluster Interactive Model Source: Action Dynamics of the Local Supercluster - The Astrophysical Journal, Volume 850, Number 2, December 2017 (free preprint)