I'm having trouble understanding an aspect of how the distances of very far supernovae are measured with this method. I know this type of supernovae have an absolute brightness. Hence we measure its energy flux and we can tell the distance of its source with a known formula.

What i don't understand is, the universe is expanding while the light of the supernova is traveling to us, thus if the source is very far it may have gone ever farther away from us by the time its light reach us.

My question is: does this measurement tells us the distance of the supernova right now? Or is it the distance from Earth back then when that light was emitted?

I know we can measure the redshift of the light and take that into account in the energy flux measurement. But since the universe is expanding in the meanwhile the wavefront of the light should also expand and thus its flux getting smaller. Shouldn't this measurement tell us the distance from Earth right now?

Was curious if during a time following the big bang, when matter has taken a solid form, but not yet formed massive, significantly gravity-altering celestial bodies, is it likely by our current standards of physics that time moved quicker relative to how it moves for us? I mean I know time and gravity are a trick subject at this timeframe, but I've no formal education or knowledge into the topic and am curious if anyone who knows better could point me into the direction of studies on this or explain why it's a dumb idea if it is lol.

Just went down this late night mental rabbit hole when thinking of a world where theoretically we lived adjacent to a black hole. Would our perception of the age of the universe differ due to the difference of the passing of time?

Is it possible that millions if not billions of years have passed in other pockets of the universe that for us time has moved faster? Or vise versa. Idk it's like 3am and the topic interests me.

(Something funny to add, I meant to post this here but first accidentally posted it to the subreddit for the Astros sport team lmfao, they still haven't deleted it and I'm curious what they'll say)

I would have though the velocities of stars before, during and after the density wave should be a little different?

Could anyone educate me on how a system with a relatively small black hole on a cometary orbit around and through a more massive stellar companion would evolve?

So as you know the Hubble Constant is 68~72km/s per Megaparsec but the expansion of the Universe is supposed to be exponential. There is even a popular theory that in the distant future the speed of the expansion of the universe would be so great that it might rip everything apart. Shouldn't that mean that the Hubble Constant is an exponential function instead? I am very dump so I'm probably just spouting nonesense, and I'm sorry in advance.

Age 28. Live in USA. Currently employed as a major airline pilot. I have a Bachelor’s in aviation science. I’m interested in pursuing a different career as a scientist. I imagine I would need to start over with a Bachelor’s in physics followed by a PhD in astrophysics. I currently work 13 days per month on average and believe I could attend undergraduate courses during my days off. Any advice or suggestions for someone who has changed careers later in life?

Also exploring the idea of becoming an astronaut since I already have the experience/background of being a pilot. But one step at a time…

Let us suppose the sun from its birth is a rogue star(somehow) with all the elements the same as today.

And is really far away from a galaxy to be affected by one in its lifetime

How would this affect life on earth other than the lack of stars and technological development

This is my first question in this subreddit. Let's assume there are two planets revolving around a black hole. One I will refer to as the "Inner planet" because it is revolving close to the black hole and the other I will refer to as the "Outer planet" because it is revolving far away from the black hole.

Let's also assume there's a portal enabling instant travel between the Inner and Outer planets.

My first question is if I travel from the Inner planet to the Outer planet using this portal and spend let's say 2 months there and then go back to the Inner planet using the portal. Would only a short amount of time(Let's say 1 week) would have passed?

Afterwards, if I were to use a rocket to travel from the Inner planet to the Outer planet and arrive there in 1 month, what would I encounter upon my arrival? Would I encounter the version of myself that had previously traveled through the portal?

Apologies in advance if my question didn't make sense.

I have few galaxies from PAN-STARRS survey with their PGC (Principal Galaxy Catalogue) and EGIPS number. I have to find if these galaxies are in the SDSS Catalogue as well. How to cross-match them. Is there a website or database that would enable me this? P.S: I have no previous experience of generating a SQL query to match them. It would nice if you could elaborate your suggestions.

A general question on orbital speeds and rotations of planets. Simply, is there a theoretical maximum value of these that would still allow the evolution and maintenance of life, and why these values specifically?

Additionally, what determines (generally) the orbital speed and spin of a planet aside from gravitational forces?

An attacking spaceship (A) is travelling rapidly towards a spacestation (C) that has 2 spaceships (B1)(B2) blocking A from reaching C.

A cuts it's primary thrusters and uses it's inertia to keep going forward, moments after cutting the primary thrusters it uses smaller maneuvering thrusters on its front and tail to rotate rapidly 90 degrees to have its broadsides facing the ships. While still moving on a course towards spacestation except now with it's broadside leading the way as opposed to the head, it fires a number of munitions (missiles\cannons\lasers).

Immediately after it fires these it uses the maneuvering thrusters to rotate -90 so that it's now facing headfirst to the spacestation and continues its journey.

The main thing being that it has not deviated from its path. It still all being a straight line from its initial point, to the spacestation.

Is this possible? Can you spin an object while on a straight path without it deviating significantly (turning\curving)

I am an amateur writer who is deeply concerned with being as scientifically correct as I can regarding the fundamental laws of the universe (where magic is not concerned). Is it theoretically possible for there to be a star system that has a planet with a moon/planet on the same revolution cycle, causing a permanent eclipse on said planet?

I am not a physicist, but an engineer. I was listening to a discussion based on Neil deGrasse Tyson's commentary. Nobody ever mentioned the behavior of a planet's fuilds as adding another layer of resonance to the problem. When thinking about systems that carry fluids (trucks or pipes), you really need to think about the fluid as it's own body. Maybe not a huge issue for earth, but what about Jupiter?

1. Does this mean every 2 body is really a 3 body?
2. Would this dampen the eventual path to chaos in 2 large, 1 small scenarios?

Thanks.

So as we all know, nothing lasts forever in our universe. Eventually, even stars burn out. I know that main sequence stars, exist by fusing hydrogen in their cores, and that each star only has a finite amount of the stuff. And that once the hydrogen is gone, most stars will start to fuse helium, which signals the beginning of the end of said star, over billions of years of course.

It's believed our sun will run out of hydrogen within another 4 billion years or so, and begin fusing helium, which will turn it into a red giant, that expands and consumes every inner planet up to Jupiter, dooming Earth of course. My question is, do we know what state the unconsumed hydrogen in a star like ours, is in? Gaseous, plasma? And could we theoretically "refuel" it with fresh supplies of hydrogen, given hydrogen is believed to be the most abundant element in the universe, and also assuming we could develop technology, that would allow such a delivery system of obscene quantities of raw hydrogen?.

Hi, I really want to know something. So we have the limitation of the speed of light. If we think a bit outside the box, does that mean that we have a limitation of a particle that travels through the entity which is the universe, composed mostly of dark matter and dark energy? So, theretically, isn't this begging the question - is this the limitiation of a particle traveling through the environment of dark matter and dark energy in the same way particle travels under water with limited speed due to its environment?

The way I want this to be is, that if you were to create essentially, the Void bubble around the spaceship, same Void as outside the boundries of our universe, rejecting dark matter and dark energy (physical matter too), wouldn't we be able to completely ignore the lightspeed limitation, as hypothetical starship would be traveling below lightspeed but the Void bubble could travel faster than lightspeed? That would essentially be cheating our universe as no matter or energy would be traveling faster than the speed of light, it is the Void bubble that is isolated from our universe traveling faster than the speed of light. Technically this would make the inside of a bubble into a pocket dimension as it would be completely isolated from the universe and it's laws.

I am not a scientist, I just thought on how we could theoretically cheat the universe. FTL by its very name is cheating the laws of our universe so I thought "hey if we don't have mass or energy and we reject dark matter and dark energy which is our travel environment, wouldn't this make us able to ignore the laws of the universe as we kind of have no interaction with it in such a case? Why would a Void bubble be eligible for its laws?"

Hello! I hope that you are all doing well! I was wondering if anyone here would be able to help me download spectra data for quasars from the SDSS catalog? I have been working to try and do this for a few days now, and I keep being somehow unable. Any help would be appreciated, thank you!

I don't mean as a person, idrc how he is as a person maybe hes great maybe he sucks but I have been recommend many things of him describing physics and science stuffs and i heard some people say he is grifter. I don't know what his practices are with book writing or whatever but I love the way he explains stuffs so I want to know if what hes explaining is some bullshits or if its good informations? I imagine to an extent the mileage may vary but in general how accurate is his high level overviews/descriptions of stuff?

Working on a project and I chose to use Matlab to model the orbit of the earth and moon around the sun (iteratively calculating net force on each and finding impulse over a time step). Right now, the accuracy of the positions is good, comparing it to NASA data, and using their precision. I then want to determine when an eclipse will happen over a certain time period (NASA says there will be an eclipse in 2026, so i’ve been doing 3 year time frame).

My current approach for determining if there is a solar eclipse is to find the plane normal to the vector between the center of the sun and the center of the moon. Then, I pick two vectors in this plane which are perpendicular to each other, and find points on the surface of the moon and sun in these vector directions (+ and -, so 4 total points for each). Then i draw a ray from the top sun point to the top moon point and see if that ray intersects the earth. I continue for the bottom points, as well as left and right points. If any of those rays do intersect the Earth, there is at least a partial solar eclipse. When I implemented this, my code did not result in any eclipses for the next 3 years, which is not true. I then implemented the code using the positions from April 8, and had it run 1 day with a time step of 1 minute. It also said no eclipse for that scenario too.

I know it’s a problem with my eclipse-checking technique and not the accuracy of my position vectors, so can someone suggest another way to determine if there is an eclipse given general position vectors and radii?

Does anyone knows if JWST has observed or looked at Alpha Centauri or Proxima Centauri yet??

It’s been more than two years since JWST started capturing most amazing images of the stellar planets and galaxies but I haven’t heard or seen of it has looked at or observed Proxima Centauri and its planets. Given the facts that it’s the closest neighbor star to our solar system and we already had confirmation of multiple rocky planets exists around Proxima Centauri..

I am really curious why haven’t we explore those planets in compare to wasp-81 or other planets which are a lot further than proxima b or c??

Genuine question.. if anyone have any info on it please share.!

Doing research for an astronomy class, and I wanted to know if the collision of two stars on the main sequence (let's assume, for the sake of the question, they're the same spectral type and luminosity), would result in the formation of heavy metals such as Gold or Platinum. New research has suggested that these elements are formed during the collision of neutron stars. Is this process also possible during main-sequence stellar collision? Or is it restricted to neutron stars due to their special properties? Sorry if this question is phrased weirdly or if I misuse any terminology!

If we could, what would it look like? How long would the transition take?

say, a photon named Josephine and a photon named Omar Habib, are dating. they are together in some point in spacetime. But for some reason, external events make them separate and go in literal opposite ways.

1-at what speed are they getting away from each other?
2-what perception do they have of one another while looking at the rear view mirror?
3- Omar's family watches them go opposite ways from affar What is the perception they have about how fast they are driving away from each other, could they measure the speed? (2x the speed of light?)

Thank you
PS - Josephine was a bitch anyway. good for him if you ask me.

1. The matter inside a stars orbit controls its velocity, the matter outside does not (given isotropic distribution) in a galaxy
2. A flat velocity distribution in a spiral galaxy is easily achieved using a normal matter distribution, however the overall velocity is a bit low
3. The correct velocity is corrected for by DM inside the galaxy
4. Diffuse DM halo is only important for gravitation lensing

cheers

I hope this is the right sub for this. I am writing a fantasy book and I’ve tried to keep all the science as sound as I can (yes, I know, emphasis on trying).

I’d like the moons of two different sizes and rotate such that sometimes they are near each other in the sky and sometimes they are far. Planetary orbit is comparable to Earth’s.

I know absolutely nothing about astrophysics, but I learn fast when pointed in the right direction.

Could someone point me in the right direction?

https://youtube.com/watch?v=9YEtVoDw-D8&si=IyxAHqAil2NA-2rZSave the Chandra X-Ray Observatory, one of the most important scientific tools we have from getting DEFUNDED by Congress! No asks for donations are in this video or as a part of the movement. Just for your voice to be heard.

In this StarTalk episode question, a viewer asks the question: "If all matter is spaghettified at the event horizon, what is light spaghettified into?". First, Dr Tyson establishes that spaghettification doesn't have to happen at the event horizon. However, then he claims that (at 14:12) light is spaghettified in a way as it is red-shifted. I think this misses the point of the question since light that is trying to escape OUT of the black hole is red-shifted, but what about light ENTERING a black hole? What happens to a photon that is on a straight path to the center of the black hole?