Astronomy and Cosmology

“Dark energy is an unknown driving force behind the acceleration of the universe, and we’re measuring the inverse-square law below the dark-energy length scale to look for a possible new gravitational phenomenon. Kapner and his colleagues use a sensitive device called a torsion balance to test the inverse-square law, attempting to shed some light on dark energy. And the results regarding the dark-energy length scale? “There are no deviations from the inverse-square law,” Kapner insists. “We see it behaves just as Newton predicted.” The test, he says, establishes that there is nothing new at the dark-energy length scale". (Source: https://phys.org/news/2007-01-dark-e…

Hi guys, I don't know if this is already present here, but I have an idea and I was wondering if you could help me out to figure if it makes any kind of sense. I might get it all wrong, but I wanted to share it before I forgot about it. So I have these three questions: 1. What if space itself is not expanding but it's simply multiplying over time? Like at the smallest scale possible the space grid is just adding new cells. 2. Furthermore, could the singularity of a black hole contain inside a tiny amount of "space" isolated from the rest due to extreme gravity, and that small amount will over time multiply to the point that it will excerpt a pressure …

Existence, the universe and how nature works, is constantly on my mind. I can't help myself. I just want to learn as much as I possibly can about reality, and I will probably keep wondering about it 'till the day I die. Sometimes I get an idea, that I've never heard about, and I think 'wow, that makes sense', so I google it to see if it's a well known theory. Sometimes it is, sometimes it's not, and sometimes I get nothing. Not even a repudiation. This is one of those. So here goes: Could most of the heat from the big bang have turned into the strong nuclear force? (The rest would then be the CBR.) Thank you, in advance, for taking time to consider m…

I'm fairly unfamiliar with data processing and data analysis in astrophysics so i'm unsure how to address certain claims as to the veracity of astronomical measurements. The paper by a crank physicist named Pierre-Marie Robitaille got me thinking. What is a respectable signal to noise ratio in astrophysics and, in particular, why a ratio of less than 2:1 for the Wmap data could be then considered an accurate recording of the CMB? What could be considered a standard in astrophysics for a signal to noise ratio that would indicate an accurate reading? If you could supply some extra reading material at the undergraduate level i'd appreciate it. 802260431_PierrePaper.pdf

Hi, everyone! Our today’s topic is “Interesting space facts”. The first interesting fact is that space is completely silent. There is no atmosphere in space, which means that sound has no medium or way to travel to be heard. The second interesting fact is that the sun’s mass takes up 99.86% of the solar system. And the last fact for today is that one day on Venus is longer than one year Venus has a slow axis rotation which takes 243 Earth days to complete its day. The orbit of Venus around the Sun is 225 Earth days, making a year on Venus 18 days less than a day on Venus. Thanks for paying attention))

There is an assertion that General Relativity predicts that black holes have zero volume, so by extension that their density is infinite. However, my understanding is that this line of thought violates the Compressability level theory of matter, so cannot be correct. Clearly, the density of neutron stars, for example, is the result of the matter within them having been compressed to the level that there is virtually no space between the nucleii of the atoms themselves. However, the subatomic particles that make up the protons/neutrons of those nucleii, and the forces between those particles, remain essentially unaffected. Accordingly, neutron stars are an example of ma…

What is dark matter? An incomprehensible substance evenly scattered throughout the Universe, or is it the border of the Universe behind the Oort cloud, from where the sunlight is simply not reflected? Astronomers Use New Data to Create Extraordinary Dark Matter Map The distance to the most distant galaxy is supposedly 13.4 billion light years. This means that the light travels all the distance without hindrance. This is supposedly a straight line, along which there are no objects: stars, galaxies, nebulae, dust, gas - nothing blocking light in a straight line 13.4 billion light years long ... This is hardly possible.

If the Earth was the size of a tennis ball, this video explains the size and scale of the universe. This video will make you feel very small.

I think this "Angry Astronaut" guy makes a great point. Can private industry compete against China? China has basically hit the tarmac with full afterburners and they already have achieved more than SpaceX or Axios combined. US private companies like SpaceX have had some significant accomplishments such as their finally successful re-landing of Starship, but I think time has ran out. China already has equal lift capacity to SpaceX and ULA and Arianne, and they are going bigger. And they are going for a unilateral space station approach which has some very interesting speculative militarization aspects.

An interesting point developed in another thread but because it's not directly related to that thread I'll just ask the question here and see what discussion forms of it. It fascinates me that NASA actually has asked this question in response to the loss of the Columbia. Brief background, Columbia is just one of many missions that had foam insulation come off the tank and break off tiles. Before whoever throws NASA under the bus, they actually ran through a lot of scenarios to evaluate the tiles and see if the Atlantis should be sent or a jury-rigged repair be made. They determined an unplanned spacewalk is a far higher risk than what had been happening. In hindsight…

On Feb 18 it will land...hopefully. This one looks like Curiosity but with more tricks. It will test a chopper and try extracting O directly from the thin atmosphere. I always thought they had to find water ice to make oxygen. It will leave behind core samples for someone to pick up in a later mission. (1) NASA's Mars 2020 Perseverance Rover Landing Animations - YouTube Here are some more details. (1) Mars 2020 Perseverance Rover - What's Different This Time? A Narrated Explanation. - YouTube Does anyone know why when I copy and paste Youtubes all I get are words and no graphic? Everybody else gets a nice colorful graphic. It is powered by nu…

I don’t want to go off track understanding time but I think I’m getting confused over the ‘universe is flat’ perspective. Does the universe being ‘flat’ just mean it is infinite in every direction?

"The mass and radius of the observable universe fit the same relationship defined by the mass and Schwarzschild radius of a black hole". I've read this sentence in the book 'Einstein's Monsters: The Life and Times of Black Holes'. Here's the calculation. What's the significance of this correspondence? Is it expected that there should be relationship between the two, and if so, why?

Do you think that SpaceX and Elon Musk can get us to Mars by 2024?

On the map of the gamma-ray sky - the electromagnetic radiation of the highest energy flowing through our universe-14 objects can hide a big secret. In a new analysis of the properties of this radiation, a team of astrophysicists determined that it is consistent with what we expect from stars made of antimatter - hypothetical objects known as anti-stars. If this were true, it would be absolutely incredible - it could help solve one of the biggest mysteries in the universe, namely, all the missing antimatter. But there are a few other things that these 14 objects could be. Every particle of matter that makes up the material we see around us, such as electrons and quarks, h…

https://www.wired.com/story/wheres-the-dark-matter-look-for-suspiciously-warm-planets/ Physicists calculated that these mysterious particles will betray their location with heat. To prove it, they’ll need the most powerful telescopes in the cosmos. Soon we'll have a cutting-edge thermometer: NASA’s new James Webb Space Telescope is expected to launch this fall.PHOTOGRAPH: DAVID HIGGINBOTHAM/NASA/MSFC WE'RE BATHING IN an uncertain universe. Astrophysicists generally accept that about 85 percent of all mass in the universe comes from exotic, still-hypothetical particles called dark matter. Our Milky Way galaxy, which appears as a bright flat disk, lives in a …

It is a well-known fact that the universe is expanding. This means that the farther we look in the universe, the farther speed away the objects there are from us. In this case, based on the Doppler Effect, the frequency of electromagnetic waves will be slide in a lower region. This means that when you look at to a certain distance with the optical telescope, the colors shift, because of the Doppler Effect. Red going to be yellow, yellow will be green, etc., and magenta slides to UV (Ultra-violet). It is not a major problem. However the visual will be false. On the other hand, if we look at a much more distant region, the optical l…

Hello! As some of you might know, astronomers have recently detected (through direct imaging) a gas giant exoplanet candidate in the habitable zone of Alpha Centauri A. This is the study: https://www.nature.com/articles/s41467-021-21176-6 For those interested, I made a video-analysis suggesting the possibility of existing a habitable exomoon around that gas giant candidate: url deleted (rule 2.7) Would you prefer to have a habitable exomoon or a habitable exoplanet in Alpha Centauri?

Russia made a great leap forward in space technology, when launching satellites from submerged submarines. I think the most important application for this would be to direct SLBMs more accurately.

On this date, 60 years ago, Yuri Gagarin became the first man in space aboard Vostok 1. 7 years later, he was killed in a crash of a Mig jet aircraft along with another Soviet air force personal named Vladimir Seryogin in what has been claimed to be mysterious circumstances. After doing some research on him I have come across two rather interestings facts. The first is that he was only 5ft 2in [157cms] tall. https://en.wikipedia.org/wiki/Yuri_Gagarin#Death Presumably I would have thought that this may have been due to the confines of the Vostok space capsule, but I find no record of that. Is my assu…

Brief description to avoid unnecessary complication. The distance from the Earth to the Sun is about 8 light minutes, so from the Earth we see the Sun at the point in the sky where it was 8 minutes ago (in 8 minutes the Sun passes through the sky with an angular distance of slightly less than two solar disks) ... It is difficult to both explain and imagine, because most likely it is impossible, that is, cosmic distances are too exaggerated. The distance from the Earth to the Moon is about 1 light second. That is, the apparent and actual position of the moon is almost the same. The shortest distance from Earth to Jupiter is about 32 light minutes. The appar…

According the theory of Relativity, nothing can be created or destroyed, meaning that when something is absorbed into a black hole, it's not destroyed but rather spaghettified to the point where it becomes part of a singularity. CNTY/Twistron Yarn generates energy as its pulled and tighten. (If you haven't seen it before I've provided a link to article with a video attached) If we created a CNT Yarn of larger size, and had half of it cross over the event horizon so that it started to pulled infinitely into the black hole where it would be infinitely tightened and pulled farther, would that constantly create energy until it was tighten to the point where it no longer funct…

Hi all, im not a physicist, but have an interest. Now given that most agree in the big bang theory, means everything is moving away from each other in a ever expanding universe. That being the case how can the milky way galaxy be going to crash into the Andromeda galaxy? Albeit in a few years time.

Hi all. It's my first post here in this forum. I came with a question to the professionals of this field. I'm interested in a shape of Hill sphere (for example of Earth). Is it known for sure that it has spherical shape? Or may be it is ellipsoid or something like it? Was any measurements of it performed?

https://apod.nasa.gov/apod/ap210328.html SuitSat-1: A Spacesuit Floats Free Image Credit: ISS Expedition 12 Crew, NASA Explanation: A spacesuit floated away from the International Space Station 15 years ago, but no investigation was conducted. Everyone knew that it was pushed by the space station crew. Dubbed Suitsat-1, the unneeded Russian Orlan spacesuit filled mostly with old clothes was fitted with a faint radio transmitter and released to orbit the Earth. The suit circled the Earth twice before its radio signal became unexpectedly weak. Suitsat-1 continued to orbit every 90 minutes until it burned up in the Earth's atmosphere after a few weeks. Pictu…