Hot answers tagged

96

Give it a circumstellar cloud of oxygen. Some planetary nebulae, such as NGC 6826, appear green because of ionized oxygen. Image in the public domain. Yes, this is a true-color image. I see no reason why you couldn't surround the star with an extremely dense cloud of hydrogen, containing a relatively high fraction of oxygen, which would absorb light and ...


65

WARNING: While this post does point to a scientific paper there are a lot of doubts about the quality of that paper and how reliable it may be. The review process of the paper, credentials of the author and validity of the claims have all been questioned. Unless or until those questions can be answered any information from it should be used with caution. ...


65

I think you're missing some knowledge here, since what you are asking about is called a binary star system and they are extremely common. Your planet can orbit the pair around their common center of gravity (the Barycenter), or you can have the binary pair further apart and have your planet orbit one of them. The second case sounds like what you want. ...


64

Update I've updated my CDF to handle eccentric orbits and customization of star brightness, and (more importantly) to show long-term seasonal effects. A few notes: Mousing over any of the parameters in the upper-left will show a tooltip with its name. Note that the luminosity slider only adjusts the luminosity by a small factor. A star's luminosity is ...


61

People are curious Humans, at least, are very curious. Shamans on spirit journeys, young men on adventures, and outcast groups in exile might all end up traveling into the night zone for one reason or another. And if they had not seen stars before, they would be amazed, and behold them with wonder. Once word got out of these stars, many of the religious ...


61

First, if the Sun went supernova scientists would be terribly, terribly confused. In order for a star to go supernova, it has to have a mass greater than at least 8 solar masses. Although there is some debate about the exact threshold, the Sun is not nearly massive enough, not even close. So if it went supernova it would be really weird. In fact, it would ...


57

C. Must not create any phenomena that would have devastating consequences on life on the planets (i.e.: no radiation, excessive heat, energy surges) except for the diminishing of the Sun's current Solar contributions. The Sun just reduces in size, energy, and mass, but otherwise functions normally. That is not possible, for three reasons. About a third of ...


43

As another answerer provided, Neutron stars already do this. So, I'm going to alter my answer somewhat to address whether there are other means by which a star-like object may exist, besides the one we already know about. In that regard, I'm afraid my ultimate answer to this is going to be 'No' or at least 'Not with our current laws and/or understanding of ...


40

How would this be possible? It would not, for a range of reasons. For the stars to coexist in such a system, they would have to be arranged in a way similar to planets in our own solar system. They cannot share orbits - two planets sharing an orbit, even in lagrangian points, are not stable over geological time. But five light-days is just too tight. ...


39

If they're avoiding both the heat of the day and the cold of the night then there are dawn and dusk people. Most likely you have four main groups, two who move constantly and two who move and settle for long periods. The dawn tribe will move until they start seeing stars, then it's time to settle until the heat of the day catches up with them. The evening ...


39

Wormhole [A,C,D,E,F,G] A traversalable wormhole would be an excellent mechanism to remove mass from the sun. A wormhole is consistent with general relativity while avoiding all of the pitfalls of violently moving mass from the center of the solar system (which could cause all kinds of orbital perturbations that would be chaotic or even fatal). [B] Would ...


38

You can always drop a chunk of degenerate white dwarf into it. If the mass of the target star + your bomb is greater than the Chandrasekhar limit it makes a pop that would startle some people. You would need at least a .4 solar mass object to do this. Operation Giant Steelie Procure a solid mass of iron .01 times the mass of the sun get it spinning until ...


35

I recommend Celestia (https://celestiaproject.net/). This is a very detailed (and free) astronomy simulator that lets you view planets, stars, constellations, etc. from any angle. You can view stars from other stars, even outside the galaxy. It's available for Windows, Linux and Mac OS. Looking at 18 Scorpii from the direction of Earth (1.75 AU away): ...


34

For big stars with the right supernova conditions, yes. First a note. There are several types of supernova. In general, a Type I supernova doesn't leave much behind. Thus it is pointless to ask whether the planet exists with a minimal orbital disruption as there is nothing to orbit. A Type II supernova generally does leave something behind, like a neutron ...


34

Phil Plait of the Bad Astronomy fame: Why are there no green stars: "The fault lies not in the stars (well, not entirely), but within ourselves". Followup: Green objects in space: "So, maybe, maybe, there is one intrinsically green star, but even then it’s controversial". But is there a star that’s intrinsically green? Zubeneschamali is the second ...


33

Total Eclipse I know this isn't directly an answer to your question, but the novelette Nightfall by Isaac Asimov deals with a civilization living on a planet in a system with six suns which keep the whole planet continuously illuminated. The people have no actual awareness of any stars beyond their local solar system, as they cannot see them and they are ...


33

@SandyBeach is absolutely correct: The sun should not go supernova, and if it did so, we'd all be dead by the time we could tell. However, assuming there's a handwaved mechanism to keep some sensors alive, there would be noticeable changes. It's important to know what causes supernovas first and foremost Supernovas occur under specific conditions, so it's ...


32

A 1% change might be feasible, but dramatic variances are unlikely. Time dilation only becomes significant as you start approaching the speed of light. You have to be moving almost 0.2C to see a 1% difference. While a star system moving at any velocity is possible in a theoretical sense, in reality I don't think you'd encounter systems moving at ...


30

Mercury vs. the Sun Mass: Mercury - $3.3022×10^{23} \text{ kg}$; Sun - $1.98855×10^{30} \text{ kg}$. Mercury clearly won't so much as jostle the Sun. There should be no major changes in the Sun's orbit around the galactic center. Composition: Mercury - oxygen, sodium, hydrogen, and iron; Sun - hydrogen and helium. The extra elements shouldn't affect the Sun'...


30

This isn't how stars are born. But yes, your premise works. Here's how you make a star, in a nutshell: Take a big cloud of gas and dust. Have the cloud grow until it reaches roughly the Jeans length, at which point the cloud is unstable. Let some perturbation - perhaps a shock wave from a supernova or radiation from other stars - create a change in density ...


30

The answer isn't entirely clear what the final state of the Neutron Star matter would be, but it would most definitely completely destroy the "Totally Normal Office Building", and most of the country... and probably most life on Earth. See this related question: https://physics.stackexchange.com/questions/10052/what-would-happen-to-a-teaspoon-of-neutron-...


30

This is more or less my best guess. We're talking about a mass of about one hundred billion tons, composed of neutrons, previously held together by a terrifying gravitational field - and now unleashed. The cup starts falling down under the Earth's gravitational attraction, but at the same time it explodes outward (so, also downward) with a velocity of ...


29

A Kardeshev Type II civilization capable of transitioning to a Kardeshev Type III should no longer be bound to a particular planet or even a single solar system. They should already be able to move populations from world to world with little effort having already mastered the ability to harness energy from thousands or even millions of stars in their ...


29

I use software called Starry Night Pro. It allows you to "fly" to a star in the database and take a picture (with or without labels and guidelines). The software is not free, but it has many graphic options (from what I can tell on the comparison page, the cheapest version will accomplish this, the more expensive versions are for telescope control). This is ...


28

Problem: even if you could just stick a blanket over the sun, it is probably already too late. The solar system formed more than 4 billion years ago, and for all that time anyone who was watching and had suitably acute vision would have been able to see Sol, and almost certainly the protoplanetary disc around it and later the planets themselves. Certainly, ...


27

If we focus on the luminosity, ignoring shell impact, we can say that inner planets of the star-system do get destroyed whereas outer might survive (to some extent). Brightness of a supernova From this question on physics.SE, we get a rough estimate of the supernova shell/nebula peak brightness at about 60 days, with a variation of 3 magnitudes (a ...


26

I spent some time putting together a project which does this to within 75lys, hosted here. All the source code is on GitHub. This definitely isn't as professional as Starry Night, as mentioned above, but it is free. To be honest, I'm not at all an astronomer so I don't know to what degree 75lys captures all interesting constellations, so take the accuracy ...


25

Black body radiation The Sun is, approximately, a black body. That means that the light it emits follows a particular spectrum according to Planck's law, with the shape of the spectrum determined solely by the Sun's surface temperature. In particular, the wavelength of peak emission can be found through Wien's law, which is also a function of temperature. ...


24

The concept you should look into is popularly known as The Goldilocks Zone. What it boils down to (no pun intended) is a formula that tells you what is the possible range of orbital radii where liquid water can naturally occur, and thus a planet where water is present can support life. You can find this zone for most any class of star. The only caveat here ...


24

Visual Discovery in Dark Areas If your scenario allows for people to venture into dark areas where stars are visible to the naked eye, then certainly that will be the easiest way for people to discover stars. Non-Visible Light Astronomy If your scenario requires people to stay in areas where stars are not visible to the naked eye, then techniques other ...


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