Astronomy and Cosmology

I thought this article in the Guardian was rather intriguing: https://www.theguardian.com/science/2024/mar/09/controversial-new-theory-of-gravity-rules-out-need-for-dark-matter As I read this, the proposal is that fluctuations in spacetime itself (i.e. not vacuum fluctuations) could give rise to "extra" apparent gravitation which could dominate over conventional gravitation at long range, thereby accounting for the anomalous rotation rates of the edges of galaxies. Link to abstract of the paper here: https://arxiv.org/abs/2402.19459 There was a previous piece on this a few months ago which I missed: https://www.theguardian.com/science/2024/mar/09/controvers…

In the movie 2001 the now defunct airline company Pan Am had gone from the airline industry into the space industry. We know that won't happen now since Pan Am went out of business in 1991 but I've been thinking of the possibility of other airline companies and private businesses in general going into the space industry. To the best of my knowledge in the USA the only organization that sends people into space is NASA which is entirely government funded. It would be better if private companies would take up the space industry since that way the space program wouldn't rely entirely on government funding and there would be more opportunities for people to go into space not t…

If you ask me we should've done this a long time ago but here is a video on a plan to bring back samples from Mars.

We could observe the present only if by reducing to the absurd , the speed with which the carrier of the image would have infinite speed up to the receiver and then to processor of the image and the processing of the image would be done at instantaneous speed. My English is bad, maybe I will be a little confused but I will try to explain: We observe in the present but everything we observe comes from a mixture of past tenses, due to the fact that the distances from objects to the light receiver plus the distance from the receiver to the information processor are different , never equal (even if the distances may differ only with a Plank length) so times when information…

What if someone designed a space ship that travelled faster than light? And they managed to prevent the space ship from crushing into another object and from disintegration (because of the speed)

Help required! Can I determine the age of the Hercule-Corona Borealis Great Wall by its” light-year distance from us? I know that “light-year” measures distance, not time. However, it has that “year” component to it. So, if Hercule-Corona Borealis Great Wall is 10bn light-year away from us, does it mean that light took 10bn years to get to earth? Or is there something else like relativity and gravity to take into account! Hercule-Corona must be old, but how old in comparison to the age of the universe – 13.8bn years? If it is very old and thus created very early in time-universe then how did a superstructure like Hercule-Coronal get to 10bn light-years long by 7.2bn light…

Being that once our star begins to run out of Hydrogen the entire solar system will die shortly after, should we not be focusing on finding other, younger systems with planets that can harbour and nurture life as well as faster space travel and most importantly, How to live on a planet without destroying its environment and having a negative effect on all other life forms on it? I realize that we are learning a lot by studying the other planets and moons within our solar system but now that science has proven that the slightest change to one planet or moon will have an effect on everything else, possibly causing changes to our orbit and/or rotation which has been sighted …

https://www.foxbusiness.com/technology/us-moon-lander-suffers-anomaly-putting-lunar-mission-risk A U.S. lunar lander that launched from Florida on Monday in hopes of becoming the first American craft to touch down on the moon in more than 50 years is now suffering from a "critical loss of propellant," putting its mission in jeopardy, its maker says. Astrobotic Technology says its Peregrine Lunar Lander began the day lifting off on a United Launch Alliance Vulcan rocket from Cape Canaveral Space Force Station at 2:18 a.m. before separating approximately 310 miles above Earth about 50 minutes later. "Astrobotic-built avionics systems, including the primary …

We always hear that the big bang started from a tiny point, smaller than a proton, that experienced cosmic inflation and expanded many times the speed of light for a tiny fraction of a second. Oh, I see, that was only the observable portion of the entire universe. Considering that anything finite can never expand to an infinite size, does that not indicate that the region of the universe we live in is probably not indicative of our universe out to a distance of, for example, a googol light years? Or Graham's number of light years? It would appear that our universe probably has a finite size. Or maybe it has reached infinity through some means we don't understand? Wa…

Under one trillionth or less percent of the Universe was examined?

Are they contra-rotating outwards? I'm referring to the light-bluish parts in this image: Mechanically, are the original vortices intiated/formed in the same way tornados are formed in an atmosphere? Mutual friction of adjacent, directionally-opposed clouds causes them to turn into each other?

Since the Big Bang I understand that the distances between galaxies and ,generally regions not bound together gravitationally have been increasing in an accelerating way. I have seen this process described as either space expanding or space-time expanding. Which is the more correct way of describing it? To my mind it should be the former. I see space time as a mathematical model (and don't see how a model can expand) I see space as the distances between objects and can understand how these measurements can be continuously increasing. On the other hand I think I can also see that the space time intervals between the galaxies might also be …

When are we going to start using hall thrusters?

Once again, I have some (maybe unusual) questions for the scientific community. I hope you can easily refute my ideas with good arguments. But first I want to mention again what we are currently supposing: 1. The limit of the visible universe is somewhere close to 13.5 billion light years away. (I am using this limit just to make my calculations easier). 2. The universe is expanding, and this expansion is pulling galaxies away from us according to the Hubble constant. 3. Whenever a galaxy is at a distance of almost 13.5 billion light years, this galaxy is moving away from us almost at the speed of light. 4. Objects that are very close to us (for exampl…

This evening in London was dark, clear, still, and not too chilly (~80C -ish) with a day-10 moon quite high in the southern sky. It was surrounded by quite a bright diffuse pale disc about 10 lunar diameters across with a chestnut-coloured fringe. Google tells me that this is typical of a Lunar Corona. However, what was even more striking was a rainbow halo (indigo to red outer) surrounding the corona maybe another 3 moon diameters wide which was quite intensely coloured for several minutes before it began to fade. It's a long time since I had regular views of a northern sky so forgive me if this is commonplace, but can a luna corona and halo occur simultan…

What is Space actually made of? I do not mean the atoms, energy, dark matter, baryonic matter, planets, dust, moons, or plasma that make up the Universe? I mean what is holding these physical structures of mass. What is the canvas we are all on? I am specifically talking about what the matter is in or on. Like if you see a painting or drawing. You look at what the drawing is of. But what is the ink or paint on? What is the canvas made of? The question we need to ask ourselves is what are we as mass, such as the planets, and the vacuum of space on? For instance we are 1 astronomical unit from the Sun. We are 150 million kilometr…

I was reading a physics problem related to astronomy, and upon re-reading it, I realized that it could be really indicated to extrapolate some really interesting physics-related information. One of the questions I thought of is: How could we measure the ratio of a planet's radius to a star? The only idea I have is to compare them when the planet passes exactly in front of the star (i.e. they are aligned with our view), but this only makes sense if the distance between the two is much smaller than the distance between us and that star system (which I think is true enough for every system except the Solar system) and if it is possible to obtain such high resolutions (a…

I cannot wrap my head around certain aspects of Time, Light Speed and various discoveries said to be "Hundreds of Billions of Light Years away". My first question is...How can scientists detect stars that are more than 13.7 Billion light years away? If the Universe is 13.7 Billion years old, light could not be travelling for more than 13.7 Billion Years as nothing existed before this. In my way of thinking, everything began expanding out from a central point so anything opposite to the earth from the centre is farther than 13.7 Billion light years to a maximum of double the age of the universe or 27.4 Billion Light years. I watched a doc that stated various boundarie…

I know the space shuttle was retired in 2011 but could a space shuttle go to the moon? I know back when we did send people to the moon it was with the Saturn V rocket and from what I heard you need a powerful rocket such as the Saturn V to make it to the moon. But if a space shuttle can escape the Earth's gravity, which it obviously can, I see no reason why it couldn't make it to the moon.

All the sources I see, repeat that the ISS spends on average about 45 minutes of a 90 minute orbit in darkness. I can't fathom why and I can't find any more accurate numbers. Only at equinox, would half of every orbit be above night on Earth. In summer and winter the orbits can vary over the day, as some orbits are in longer days and some in longer nights. However I'd like to ignore that variation and consider only the average times. First, the ISS is raised above the surface of the Earth, so it is in the sun more than the surface is. The higher a satellite is, the less it will be in the Earth's shadow. For example, the moon is in sunlight about 100% of the time…

The Earth, and to my basic uneducated knowledge, actually all of the planets and other bodies are uneven in mass distribution. The Earth has a famous "low gravity bubble" in the Indian Ocean. LIkewise uneven gravity is an attribute of other planets. Previously in life I was explained to that the interior of the Earth, as well as the Sun, were so fluid that they were virtually perfectly evenly distributed for mass. In the last 20 years or so it has become common knowledge that for the earth and other planets this is not true, although scientists do not have perfect confidence in how to understand the observations they have made that show that indeed there is a "lumpy…

Stuart Kauffman has done many videos about the fine-tunning problem of the universe. I have watched all of them, and I still do know exactly how it is problem. It has been mentioned that this universe, if it is the only universe, is improbable in various readings I have come across. But I have yet to really understand exactly how the probability is calculated. This is how I am confused about why we need a multiverse. Let's say there were x possible universes. 0.1% of them have life. Okay, now, from our perspective, after it happened, why should this seem improbable? it has already happened! As an analogy, I have a glass of water. If I point out 1 h2o …

How to use this photo to estimate the distance from the Earth to the Moon during the annular solar eclipse on June 21, 2020. We only know that the distance from the Earth to the Sun that day was 152036000 km. Please help me with this difficult task - I've been working on it for a week, but I can't find anything worthwhile on the Internet.

Is there any way to extend the life of the Sun forever or is this not possible with futuristic technology?

This comet is currently in the news. Many articles comment on its green appearance. However I have yet to come across a full explanation for the colour. The closest I've got is that it is apparently fluorescence from gases in the tail, excited by UV from the sun. Does anyone have more information? What gases?