Astronomy and Cosmology

Hi, See: https://constantecosmologique.fr/ available in English What is your opinion please?

If microbial life is discovered in Venus' atmosphere, and samples are collected, will science be able to tell us whether its ancestry somehow found its way there from Earth, or whether it's definitely a product of abiogenesis on Venus? Thanks GIAN 🙂

Apparently the Orion Project for nuclear powered spaceflight asserted that by this method with an acceleration of 1G an Orion spaceship could attain a speed of 10% of the speed of light (c.) Mathematically, how do I work out 1. the length of time it would take to get from 0 to a speed of c/10 (ship's time,) and 2. what would be the distance travelled in that time? Cheerz GIAN🙂

Do I understand that right: In next video it says: The mass of planet Earth divided by it's radius=it's gravity? Video link removed by moderator Video link removed by moderator

Earth has an atmosphere that prevents particles to reach Earth’s surface, and the Sun has an atmosphere that prevents particles from the universe to reach the Earth. Or not?

Terraforming planets will take a back seat to building spacecraft that can be "all the comforts of home." Why make the effort to terraform Mars when you could much easier build a giant spacecraft that can travel for decades without needing anything, except to stop occasionally at an asteroid to collect water-ice for water, air and fuel, and some useful minerals.

If we took two lines leaving a single point and then some where in far distance the outer sides of each would come together. Could this be how the universe is racing away because its pull itself into itself in the distance place?

Hi Just been watching a video on PBS space time (you tube channel) on black holes (well building modelsi a lab which is also interesting) this is really interesting with Hawking radiation being apparently responsible for black hole, mass loss . This got me thinking if white holes are the opposite to black holes as they emit energy rather than pull it in, and a white hole is possible at the other end of a black hole, are these also perhaps responsible for mass loss. I think the two being linked is some sort of theory or idea anyway, but would it need a model where we take a black hole and a corresponding white hole would emit mass = to that taken in by the bla…

Once you cross over the event horizon of a black hole you cross the point of no return. The speed of light is 186,000 MPS but once you cross over the event horizon you would have to have a speed faster than that to escape from the gravity of the black hole and nothing can move faster than 186,000 MPS because as weight increases with speed, once you reach that speed your weight becomes infinite so it would require infinite energy just to reach light speed. That is why you can't escape from a black hole since the escape speed is faster than the speed of light and you can't go faster than the speed of light according to conventional physics. Anyway, I was thinking, if …

This wasn’t my idea but Edward Snowdens which I heard on an episode of Startalk and it just struck me as a very compelling argument. He posited that an intelligent species would have a relatively small window of broadcasting radio signals in the clear before they started encrypting all their radio communications to be indistinguishable from background noise as a matter of course. Personally I can’t think of any reason why this couldn’t be true and it makes perfectly good sense. It also makes me think that it may already be happening but that’s besides the point. What do you guys think?

I am stumbled to see a young boy is able to present a simulation of how moon formed and how the trajectory formed by the moon. Nice theory by young man .Here is the link

Hello, I would like to share with you the info we have so far about habitable exomoons: 1. We have detected 9 exomoon candidates, but none of them are potentially habitable. 2. A habitable exomoon would have a mass between 0.25 and 2 Earth masses. 3. The mass of the host planet has to be at least 3 times the mass of Jupiter, and it should not be tidally locked to the star. 4. A study has identified more than 70 gas giant exoplanets that could host habitable exomoons, but all of them are located far away. 5. Within 100 light years, there could be around 33 habitable exomoons orbiting Sun-like stars, 109 around K-type stars, and 121 in red dwar…

Mars would appear to have many channels and alluvial fans that indicate that at one time it had water and maybe even seas but at the time this is thought to have taken place The Sun was significantly dimmer than it is today and unless Mars had a vast thick atmosphere this would seem unlikely. The Earth is thought to have frozen completely over at least twice in geological time so IMHO a balmy Mars with rivers and seas seems unlikely. On Earth large ice sheet often have lakes, streams, and rivers under them and we do see Moons that are ice covered but far enough from the sun that ice is stable. Mars is close enough to the Sun for ice not to be completely stable and s…

If we can create nuclear bombs 1000x hiroshima, wouldn't it be fairly simple to use it to power space ships which could accelerate to the point where a trip to the outer planets would take days rather than years? Is it true that this is already quite possible, but governments won't let us do it because of the potential dangers of nuclear accident? Cheerz GIAN xx

Hi all I would like to try and build a solar observer as detailed here https://www.space.com/15614-sun-observing-safety-tips-infographic.html Right now I have 2 pieces of card one is square with a pin hole in the center the other is just a piece of scrap a4 card.l The projector does work. I have got a basic pinhole projector working, is there a way to link distance from hole to the size of the projected image, ? Or the optimum size of hole and distance to where I am projecting to? Thank in advance for any help II can probably use a system lke this in a school or at the South Devon Tech Jam if we decide to actually do more than simply comput…

Just been reading the above article on Did a supernova trigger the late Devonian extinction? https://physicsworld.com/a/did-a-supernova-trigger-the-late-devonian-extinction/ Asf we think there was life on Mars a long time ago, would the rocks brought back from Mars by the newly launched Perseverance rover be tested for these radioactive isotopes too, to figure out if any radiation also reached the surface of Mars. So namely this seems to be: Samarium-146 Uranium-235 Plutonium-244 So some digging as to what protects us from Solar Flares What Protects the Earth From Harmful Solar Flares? Updated March 10, 2018 By Tammie…

Hi again. I hope everybody is well. Without further ado, is there any appreciable difference between matter that has gravitationally collapsed from a primeval cluster made up of mostly hydrogen and matter that has collapsed several times within a certain galactic region? I suppose matter that collapses again and again in regions where many supernova explosions have taken place before would be richer in heavy elements. Could the wild variation in the types of stars as reflected in the Hertzsprung-Russell diagram reflect this variation in the "degree of collapse" that there is in the universe? My intuition tells me that, if all stars had started up from a uni…

The new cosmocalculator is out they had to change the host site. There is still some bugs being resolved however they increased the flexibility of the calculator http://jorrie.epizy.com/LightCone7-2017-02-08/LightCone_Ho7.html?i=1 [latex]{\scriptsize\begin{array}{|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|} \hline z&T (Gy)&R (Gly)&D_{now} (Gly)&Temp(K) \\ \hline 1.09e+3&3.72e-4&6.27e-4&4.53e+1&2.97e+3\\ \hline 3.39e+2&2.49e-3&3.95e-3&4.42e+1&9.27e+2\\ \hline 1.05e+2&1.53e-2&2.34e-2&4.20e+1&2.89e+2\\ \hline 3.20e+1&9.01e-2&1.36e-1&3.81e+1&9.00e+1\\ \hline 9.29e+0&5.22e-1&7.84e-1&3.0…

Does anyone know how small a nuclear explosion can be? The smallest I could find is the Davy Crocket. "The smallest, known deployed nuclear bomb was the W54, which had a blast yield equivalent of between 10 and 20 tonnes of TNT (in the neighborhood of 1/1000 the power of the bombs used on Hiroshima and Nagasaki)." Is it possible to scale this down even more so you have tiny nukes that don't weigh very much but they can put a huge impulse on a pusher plate of a small, unmanned, interstellar probe? "Daedalus would be constructed in Earth orbit and have an initial mass of 54,000 tonnes including 50,000 tonnes of fuel and 500 tonnes of scientific payload. Daed…

Hi, I have read here under (2.1) that [math]c^5/(G \hbar \Lambda_{s^{-2}}[/math] is a "fundamental pure number" It's the word "fundamental" that questions my mind. What is that fondamental notion please?

Dear scienceforums.net, This would be my second posting and thought this would be the proper section to put this in. I've been trying to construct a generalized python simulation for any arbitrary n-bodies with predefined randomly assigned momentum and velocity. So far it was going well and even the initial run through went smoothly without many errors to be fixed but when graphing the data it seemed to me to be incomplete. Either I was shifting through the data wrongly, the initial conditions were off enough to not allow for a smooth nearly closed n-body system, or i've been wrong about the whole program apparatus to begin with. I should note that I use something c…

Hi This is probably a really simple question, but I have written a small python application that adds two numbers together, and I want to expand this so there are more entry boxes so I can make a program that can solve a drake equation for a given set of figures. This is more of a proof of concept and personal challenge, Looking at the equation on WikiPedia https://en.wikipedia.org/wiki/Drake_equation Am I right in thinking that I have to multiply all the values together ? as this just shows dots between the various variables. I think I remember reading somewhere that dots in equations mean multiply but that was years ago. Writing a…

Physicists Announce Potential Dark Matter Breakthrough https://www.scientificamerican.com/article/physicists-announce-potential-dark-matter-breakthrough/ Just spotted a link to this., so my question is Does this mean that Axions will appear on the Standard Model of particle physics. ? Paul

(Sorry if this seems obvious/stupid) Correct me if I'm wrong. AFAIK when temperature is decreased, the molecules become closely packed, thus increasing the density. Then how do we say that the universe was extremely hot at the beginning when it was all packed into a few cubic centimeters?

Looking at space and time, relativity, and matter, I have prompted a question in my head. If time is reactive to something, it implies that it travels. Photons have mass when they are traveling and they travel at the speed of light. It takes around 8 seconds for light to travel from the sun to Earth. The same concept can be procured from terminal velocity of a falling object. It reaches a set speed based on its mass to resistance of the matter it is traveling through. So, the thought in my head is that space itself has resistance. Since light is composed of photons, and they have mass, then the time it takes them to travel a distance implies that there is a c…