hello everyone, I'm an 18-year-old student with a passion for stargazing, and in my free time, I created a Star Constellation Quiz App. It’s a fun way to test your knowledge of the night sky, learn new facts, and maybe impress your friends during your next stargazing session. This app is a personal project, and I’d really appreciate your feedback to make it even better. It’s free on the Play Store without ads. I don’t make any Money from it. —feel free to check it out and let me know what you think!

I just want feedback to improve my apps :)

https://play.google.com/store/apps/details?id=com.csk.sternbilder&pcampaignid=web_share

Hey there all space enthusiasts and astrophiles! So I'm a 17 yo currently in the second last year of my high school. I am very much interested in space exploration and future tech developments and it's my dream to have a space startup of my own (similar to spaceX but more innovative).

I want to develop new propulsion systems, new spacecraft designs and basically do a lot of innovations in how the present tech and communications stuff work beyond earth. I'm very much inclined on the sci fi side of it. Maybe am just day dreaming but I want to give it a try. My parents have told me to pursue an engineering degree of my choice but am really confused over three- Aerospace Engineering, Mechanical Engineering or Engineering Physics at research focused institutes. I read the latter is more theoretical so idk if that is what I want. I love Physics btw, if that wasn't obvious. I don't know which field will provide maximum advantage to my ambitions and merge my science and business sides.

I'm not sure if this sub would be right to post this but I thought to give it a try. Thanks to anyone who reads this.

Why cant be there like -2 billion degree

Hi, I know this question has already been asked a million times, and I picked up some stuff from already existing posts, but most of the time advice is either sctrictly about steps to take to get a job in astronomy, or "buy a telescope and a constellations book:)", plus a lot of the askers are high school students and/or US citizens. None of which are my case unfortunately.

So, long story short - I'm 19 (third year of uni, the major has nothing to do with science), live in eastern europe (ukraine), miserably failed my physics, and basically failed chemistry and math when I was in high school. I'm not really expecting to change career paths, at least right now. One of the reasons is I want to take it slow and steady and see where it takes me, and only whenifwhen I build a solid foundation think further. Currently, this is more like a blazing passion I found very recently, that I hope doesn't turn out short-lived and that can be turned into something beautiful.

For some perspective I want to list the things I'm doing/planning on doing:

-the Khan academy Cosmology and Astronomy course

• Cosmos series by Neil Tyson
• Astronomy notes by Strobel
• Cosmology for the curious by Perlov and Vilenkin

Maybe you have something nice for me to add to the list.

Now to one of my main questions: background in highschool-level sciences. I'm sure that if I want to go past the "ooh that's the __ star! pointing at the sky pretty." level I NEED it. Now, without the school pressure, I am perhaps starting to like this stuff. I want to do it as I'm learning about space but I'm not sure how to go about it. Under most posts, since the people that ask are still at school replies just say "pay attention in your math classes" or something along the lines. And what should I do, then? Do I literally find grade 7 chemistry, math, and physics textbooks and just go through each of them? (if yes good book recs please) Or is there a smarter and more efficient way? Do I just consume everything Khan academy has to offer regarding science courses? Or do I get to learn everything that's necessary as I'm reading those entry-level cosmology/astronomy textbooks I mentioned above? Basically, I want to be able to learn about the hows and whys in deep, but still keep it astronomy-related as much as possible.

And for a secondary question that isn't required to be answered but I want to put it out there just in case someone has similar experience and some advice: I mentioned that I live Ukraine, is it possible to just completely avoid sources in my native language? Is there a point in doing that? Even if, and that's a huge if, I seek higher education in astronomy, it won't be in Ukraine in Ukrainian, I don't want it to be. Plus I just looked it up, I don't think my city has any active clubs or stuff like that, so I won't even be able to take this hobby outside haha, except for maybe a pair of binoculars. So I think me keeping the learning sources strictly in English shouldn't be a problem, especially considering how little I know about astrology and space, I already know more of it in English rather than Ukrainian/Russian. But I wouldnt mind hearing other people's perspective who are also from non-english speaking countries.

I’ll start first, I wanna go to space because it is a unknown. Like I just want to explore and see how it is to be in space.

Hi everyone! I was wondering if anyone has already done the human spaceflight certificate and the CAC over at the spaceflight institute. I've been trying to do some research but have not seen anyone talking about it. I wanted to know if it was credible or if anyone's already gone through the program? Thank you!

Hey folks, thank you for the great content on this forum! I love reading the interesting posts and comments - I am clearly on the lower end of the IQ spectrum in here. However, I’d love to change that!

Does anyone have any recommendations on must read books related to space? Especially relevant to my current interest is the business of space, especially the recent commercialization of the industry. Having said that, I’m interested in pretty much anything.

Thank you!

I have seen documentaries saying we are seeing earlier and earlier galaxies closest to Big Bang. However I always wondering how this is possible considering nothing travel faster than light, and earth is not even formed yet when these galaxies are formed, so how can we see these galaxies? In other words, when these galaxies are formed, their "light" travel out and when these "lights" reaching where earth is now located in space, the problem is earth is not even formed yet! By the time earth is formed, the event (or "lights") should have long gone and we should not able to see them now. Am I missing something?

How can i start as an indie dev or my own startup in Space tech where i am from a CS background, i have no idea and if you have any examples then pls do tell.

The SpaceX rocket will launch during the late afternoon so its descent into the Indian Ocean is visible.

There are a lot of explanations for Fermi Paradox, and I think some of them together caused the phenomena we saw, so I synthesized some of them into a coherent narrative below. In short, life is abundant, life to intelligence is the first great filter coming from randomness in evolutioin (so it takes time and space), but some civilization will occur and they all go extinct at certain point by themselves or when they meet others and don't get along with each other, and if they do survive, they as a whole enter into next level of arena, where the game repeats. Moreover, the high level intelligence remain stealthy to lower ones for safety reasons.

The universe has existed for about 14 billion years. Several generations of stars have burned and exploded, scattering enough metals into the interstellar medium to form life. The Milky Way galaxy was formed slightly later, around 13.6 billion years ago. About 4.6 billion years ago, a dense region within the Orion Arm's interstellar cloud collapsed under gravity, igniting the Sun, with the remaining matter forming the planets that orbit it. Earth formed around 4.5 billion years ago, took several hundred million years to cool, and stabilize its orbit. Primitive life appeared between 3.5 and 4 billion years ago and began to evolve. Humans appeared roughly 5 million years ago. Civilization began with the use of tools and technology, with primitive stone tools being used about a million years ago, the emergence of language around 200,000 years ago, and ancient civilizations forming about 6,000 years ago.

The evolutionary history of life on Earth can offer insights into the timescales of civilizations in the universe. Although life can form under different conditions, there are common factors, such as the need for macromolecular substances capable of forming complex structures, and a solvent to facilitate material exchange with the environment. The approximately 100 elements in the universe formed gradually, with heavier elements being rarer, and the most abundant elements are several orders of magnitude more common than the less abundant ones. Considering the chemical properties of elements, organic macromolecules with carbon chains and water are the most likely forms for life to appear (in the first place).

I believe that life is widespread in the universe. Given a suitable star and the right elements on a planet in the habitable zone, amino acids can gradually synthesize, and over billions of years, evolve into life with universal fundamentals but specific forms. Life formation requires certain conditions and sufficient time; these requirements may seem stringent, but they are relatively simple for the universe with abundant space and time. The first Great Filter happens at the transition from life to intelligence. Life evolves through natural selection and random mutations. We can think of the evolutionary arena as a plateau with peaks and valleys. Animals randomly move in different directions over time, leading them to ascend or descend certain peaks. Occasionally, tides come in and eliminate all animals below a certain height, and such a cycle repeats. Eventually, the system stabilizes, with each animal(s) occupying a peak where they have reached an optimal local solution (ecological niche), leaving no room for further ascent. There may be higher peaks elsewhere, but reaching them requires animals to abandon their current advantageous form, descend into a valley, and risk being wiped out by the tides. This explains why evolution is slow, as species in stable environments evolve into their corresponding ecological niches, where their form is the optimal solution for survival as long as the environment remains stable. Over billions of years, life has undergone this repeated evolutionary process. Finally, around 2 million years ago, climate changes led to the aridification of East Africa, causing widespread vegetation die-offs, forcing a group of ancient apes to descend from the trees and walk upright on two legs in search of a new home.

The second Great Filter, and possibly the one we are currently facing, is the leap from mastering technology to entering interstellar space. "A galaxy is about 100,000 light-years across. At 1% of the speed of light, a civilization or self-replicating machine could cross it in 10 million years. Why is the universe still empty?" This is a form of question posed by the Fermi Paradox. With a sense of civilization's time scale, it becomes easier to explain. The timescale for civilization formation is about a million years, but once a civilization begins developing science and technology, this timescale compresses to a century, and technological progress will only further compress a civilization's timescale. The more advanced a civilization is, the longer a hundred years will seem, let alone a thousand or million years. Therefore, the idea of slowly colonizing the galaxy at a snail's pace is implausible. The purpose of expanding beyond the solar system is because local resources can no longer meet the civilization's needs, which means that this civilization could use sufficient resources within the galaxy and has mastered technology several eras beyond the atomic age, but before that, it is very likely to self-destruct. Although, for some reason, it is not impossible for a civilization with a timescale of a few decades to spend a thousand years reaching a target 100 light-years away, considering the first Great Filter and the nature of such behavior, the probability of it happening becomes very low, and more unlikely actions will only further reduce its occurrence. The universe is vast but still finite, and when the probability of an event becomes too small, even if it is theoretically possible, it may never happen in the entire history of the universe or its distant future. Therefore, the Milky Way may have many planets with life, some of which might have developed intelligent civilizations, but they are all trapped locally. In the entire universe, other galaxies might be similar, with some even producing one or several interstellar civilizations that may have encountered and communicated with each other. Beyond that, perhaps every few thousand galaxies that have birthed interstellar civilizations could produce one that develops into an intergalactic civilization traversing its galaxy cluster at near-light speed. Each possible scenario above reduces the probability by an order of magnitude or more. The evolution of civilization is the evolution of technology, and the use of technology carries risks. The more advanced the technology, the more a civilization can impact its environment and leave a mark on the universe, but when they fall, the greater the destruction that technology can cause. So, one explanation for the Fermi Paradox is that the universe is vast, life, intelligence, and even more advanced civilizations may appear, but with each step forward in technology, the probability sieve makes the most influential civilizations increasingly rare. The distribution of civilizations in the universe resembles Gabriel's Horn, with an infinitely large base and a rapidly narrowing top. The curve of this horn is not smooth, with abrupt contractions representing the Great Filters. The first Great Filter is natural and not caused by humans, arising from the randomness in the process of natural selection. After that, each Great Filter is the same, all human-caused, and all due to one reason: intelligent individuals meet, interact, develop together until one day, they mutually annihilate each other. Of course, if fortunate, they can avoid this bad outcome, sustain a larger collective through certain means, and step into a bigger universe as a complete and harmonious entity. They could enter their galaxy group (about 10 million light-years), their local supercluster (100 million light-years), their supercluster (1 billion light-years), and structures so large they defy description. At the highest levels of the horn, there may have been only a few, a dozen, or perhaps more of these civilizations in the entire universe. But no matter how many, curiosity rather than the survival instinct drives them to explore the broader universe, to experience the most intense and lively aspects of the universe, to witness the formation of supermassive black holes, to observe neutron star mergers up close, to explore the deepest mysteries of the universe, and to understand reality itself. During their journey, they might have seen countless civilizations still confined within their solar systems, halted before the second Great Filter, and the destruction of these civilizations often took with them the life on their planets that had taken billions of years to evolve, extinguishing any hope of starting over. They would not attempt to intervene, but unlike our indifference to the struggles of ants, these civilizations, like them, possess intelligence and free will, filled with curiosity about the same universe, longing to explore broader horizons. Their choice not to intervene is not out of coldness or indifference, but because these civilizations, which have yet to pass the test, are internally divided, distrustful of each other, unable to form true unity and harmony. To these advanced civilizations, those that fail to pass the test are dangerous. More advanced technology will only lead these immature civilizations to expand their distrust and conflict in dangerous ways. If such civilizations fail to overcome their internal contradictions and violent tendencies during their evolutionary process, even with more powerful technology, they will only exacerbate their self-destructive tendencies, and they might even bring this destructiveness to a wider universe. In extremely rare cases, perhaps out of pity, they might leave a barely perceptible ripple in space-time, pulling back a pure-hearted civilization on the brink of destruction due to an accident.

The journey continues, and they are lonely as individuals. They want to know if there are others like them in the universe. They look forward to meeting other similar beings, sharing each other's history, technology, and beliefs. Over a long period, they finally encounter others, one, two, three... These civilizations begin to contact each other, carefully exchange, learn from each other, and develop together.

Humans have come a long way from a million years ago to today. Using the imagined community and agreements, we have gradually incorporated more people into larger structures, experiencing hardships and setbacks along the way but ultimately succeeding. The current largest structure is the nation-state, built through beliefs, ethnicity, and constitutions. Throughout history, technological progress has prompted more people to meet earlier, forcing people in different structures without mutual benefits to resort to traditional solutions from their ancestors, war. In the 15th century, the maturity of ocean navigation technology led to the Age of Discovery, followed by centuries of bloody progress. In modern times, relative stability was achieved through mutual benefits brought by trade. However, ethnicity, nations, and the so-called glory that comes with them are still the largest binding concepts that humans can truly understand and grasp, leading to World War I and World War II. The most advanced technologies were brought to the battlefield, tearing hundreds of thousands of people to shreds in batches, and resources far surpassing those invested in science during peacetime were poured to develop the most effective killing weapons. In the end, after that war to end all wars, nuclear weapons, the most destructive technology ever mastered by humanity, were born before any larger structure could emerge. Civilization will not realize its predicament; it will not stop moving forward and will continue its progress. The development of communication technology brought the internet, and within a few decades, people across the entire globe were drawn into the same community. People began to curiously communicate with others on the opposite side of the Earth, sharing views and cultures, and promoting mutual learning. From nature and nurture, people are different from one another, and so are the nations they form. In the past, to unite, people established stable collectives through nations, sharing a history and culture that made them proud. But when nations meet, the legacies that people cherish from history become a burden. To unite more people together, it was necessary albeit unrealistic, in effect, to first remove the tools that bound them to a particular group, while simultaneously creating a new tool to bring all those who have been freed from their bonds together again and start developing anew. This echoes the previously mentioned plateau of evolution, where, to break free from a local optimum and continue progressing, one must first pause, or even regress during trial and error, descending into a valley before climbing again. The term "global human community" has existed for a long time, but like many other terms that refer to ideals that people aspire to but have yet to realize, people still carry the weight of history and do not know how to achieve them. This is because the immediate problems to consider are already overwhelming compared to distant goals. But civilization is unaware of this, and technology will continue to progress. Two samples are not enough to predict whether the scale of total war will cause greater destruction with further technological advancement. Precision strikes may achieve objectives while curbing casualties. But aside from these, black swan events like the Cuban Missile Crisis will not be the last. In the coming centuries, more technologies will emerge. Humanity can win countless times, but Death only needs to get lucky once. This could also be a reason for incentivizing humanity to step into space sooner, to spread to other planets.