Hot answers tagged

99

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 ...


85

No. Life on Earth and our solar system in general would not be harmed by this sudden universal destruction. Everything outside of the Solar system affects us via electromagnetic radiation, gravity, and "matter transfer". The EM radiation flux is too weak to really do much, other than marvel at through telescopes. With the rest of the universe gone we'd ...


78

Unfortunately, no matter how much pure gold you add to your mass, you will never end up with a star. The reason for this is that fusing gold is an endothermic process, meaning that it requires energy, rather than releasing it. In fact, all elements with an atomic mass greater than or equal to that of iron consume energy upon fusing, rather than releasing ...


72

We wouldn't even notice for several years. The closest star to us (aside from the Sun) is Alpha Centauri, which is just over 4 light-years away. That means that whenever we look at Alpha Centauri from earth, we are seeing light that left the star over 4 years ago. If Alpha Centauri were extinguished today, we wouldn't even realize it until 4 years from now! ...


67

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, ...


66

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 ...


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

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. ...


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 ...


56

This star would not fuse gold. Fusion reactions producing elements beyond zinc-60 are not energetically favorable; they are endothermic, and so consume energy. Several elements heavier than iron are formed through this fusion chain and subsequent decay (cobalt, nickel, copper and zinc), but these are unstable and decay back to iron, meaning that iron is ...


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 ...


41

Frame challenge: It was not them who disappeared, it was us. What is more plausible (but still a twist in the laws of physics), that an entire universe vanished or that a single solar system in the outer rim of a galaxy vanished? (Occam's razor) It was not the Sol System that remained, it was the Sol System that was shifted to another, empty, reality. ...


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 ...


37

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 ...


36

If you’re aiming to eke out the universe for as long as possible then ‘turning off’ your stars isn’t that good. A better plan would be star lifting. This is, in effect, turning off the star by pulling all of its fuel away (Note: Only very advanced, already powerful interstellar civilisations need apply). It might help to have a Dyson swarm already at your ...


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 ...


33

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 ...


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

X-ray radiation at the orbit of HDE226868 Cygnus X-1 is famous as one of the most powerful X-ray sources in the sky. According to the US Naval Observatory, the max flux of Cygnus X-1 (near the bottom of the last page on the link) is 1.2672 Crabs in the 2-10 keV range. 1.2672 Crabs is equal to $3.04\times10^{-11} \text{ W/m}^2$. I have the distance to ...


30

Although astronomers have considered this phenomenon in the past, the data indicates that this isn't how stars are born. That said, 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 - ...


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-...


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