Astronomy and Cosmology

Can a planet be hurled by a star that's gone nova, or by any other means? If so, would it careen through space at high velocity, and keep its pace, seeing as objects in motion don't slow down unless acted upon by a force? Or would intergalactic gravity slow and trap it? However, if so, what if that event occurred in a nearby star in our galaxy -- would the planet be able to cruise through our planetary system at near its original high velocity? I'm just testing the feasibility of an external planet colliding into Jupiter or a smaller planet (like Mars/Earth/Venus).

1. Is it wrong to think of ZERO-POINT ENERGY as Particle-Waves, that have lost there energy, have reached there biggest size and lowest density. 2. What age was the Universe, when zero-point energy became part of the Universe. 3. As long as stars are shining, is zero-point energy increasing.

there's a theory that says that our universe may only be a black hole. if this is so, we have black holes in our universe, then would that mean that black holes can exist in other black holes? another enquiry about this, is how would the black hole even get into a different black hole in the first place? would it be possible for a black hole with strong gravity (this is by black hole standards) to suck in another black hole with lighter gravity?

Does the earth's rotational axis ever pivot through a point where it is tangent to the surface of the sun?

this is just a theory i thought up in science class today when talking about galaxies, feel free to say w/e u want It starts with a star. A Blue Supergiant. When star dies, it will super nova, collapsing into a Supermassive black hole..Material is shot accross space by the large explosion. These materials will swirl around the black hole until stars begin to form..These stars die, creating for materials for more stars to form..Process goes on and on, creating planets, stars, and perhaps life...

Swift satellite has imaged the oldest object in the universe: http://www.nasa.gov/mission_pages/swift/bursts/cosmic_record.html

I would like to play dummies advocate. From my understanding there are magnetic fields for just about anything with mass? And normally the more mass, the larger the field and strength of it? But, I have more mass than the magnet in my hand, which I guess is not the case in terms of density, but collectively ... it has a stronger magnetic field. Anyhow, as you can see magnetism is on my brain. I would imagine there is some theoretical topic phrase for the thought experiments involving electro/magnetism and what it's like at or near BH. The questions turning my noodle stiff are, if it's ... there, Is it possible for the mass that lies past the EH to ... exhibit a…

Do you think that the Universe happens randomly, or is there something that decides what happens, and what time etc.

This is just a few things of how all life could unexpectedly end... im kinda tired so i cant think of much 1. Huge Solar Flare from sun could fry our atmosphere, along with us 2. Gamma ray burst from light years away could smack us and vaporize the atmosphere 3. Thats about all i can think of atm, feel free to add, i know i will =)

I've been reading a bit lately about the possible fate of the universe. So far I've seen a few models, and they all seem interesting to me. I've seen threads about these prophecies individually, but I'm not entirely sure which one is most plausible, so I'm curious as to your ideas. First off is the Big Crunch, the idea that when there is enough matter in the universe, gravity will cause the expansion to move backwards, thus collapsing the universe into a black hole singularity.The next one I found was called the Big Chill, the idea that as the universe is expanding, matter will get spread more and more thinly, until the temperature approaches absolute zero.After that, the…

I was wondering what anti-matter is and what its relationship with normal matter is any one know?

Kepler spacecraft was successfully launched on 6 March. It's job is to watch a particular patch of 100,000 stars for several years to detect transiting HZ (habitable zone) planets which are roughly about earth size. If anybody knows more about the Kepler mission please contribute comment. http://kepler.nasa.gov/ This website has an FAQ. My understanding is that HZ planets are ones whose semimajor axis (average distance to star) is 0.95 - 1.37 AU adjusted for luminosity. That might be wrong but it is something like that. The idea is that for a star as luminous as the sun they look for planets whose distance is around the same as the earth's, namely fro…

Imagine a SETI program on a planet at 4 light years away (nearest star system from us). What can you pick up from earth? We're broadcasting countless simultaneous things on the same frequencies (how many FM radio channels exist that broadcast on 92.4 FM (39000 hits in google), how many phones are in the same frequency, how many TV stations)? While these signals are located on different places on earth, and don't seem to interfere with each other here (because one source is much stronger than the other), at 4 light years, the different locations on earth are no longer of any significance, and all signals seem to originate from one source (the tiny dot called "Earth").…

Stephen Hawking hospitalized, reported very ill Published: 4/20/09, 11:25 AM EDT LONDON (AP) - Famed mathematician Stephen Hawking has been rushed to a hospital and is seriously ill, Cambridge University said Monday. The university said Hawking has been fighting a chest infection for several weeks, and was being treated at Addenbrooke's Hospital in Cambridge, the university city north of London. "Professor Hawking is very ill," said Gregory Hayman, the university's head of communications. "He is undergoing tests. He has been unwell for a couple of weeks." Hawking, 67, gained renown for his work on black holes, and has remained active despite being diagnosed at 21 …

Hey guys, I was discussing with a friend about the evolution of stars, our sun especially. It's now absolutely well known that the radius of a star when it turns into a red giant is increased a lot, but he asked me whether there is a formula or any other way using which you can calculate this radius increase yourself. Of course there must be some way, and I couldn't answer him. So is there a formula, or other way so you can calculate yourself what the radius of our sun (for example) will increase when it turns into a Red Giant? Regards, shade

I was waving my phone around in the dark and i noticed that it left a trail of light like it was in two places at once what causes this?

What would happen if the magnetic field of Earth was shut down for a second??? As I understand it, the magnetic field protects us from most of solar radiation. So, would this radiation have time enought to hit Earth in full force, if Earth's magnetic field did turn off for just a second? And if it did, how much damage would the solar radiation do to living beings and electronic equipments??? Would it burn everything??? Would it be the end of the world for us humans??? The reason for this question is the upcoming swap of the magnetic poles. I'm rather worried that during the incident, the magnetic field might go off for a while. Is this probable?? Mind you,…

In experiments like LIGO we want to observe extremely weak gravitational waves from sources millions of light years away - we are assuming that their strength decreases like R^-3. But because of this distance, even slightest interactions with the vacuum and other objects on the way, could diffuse/absorb them - and so the amplitude would decrease exponentially, making such observations completely hopeless. In November 2005 LIGO has reached assumed sensitivity "At its conclusion, S5 had achieved an effective range of more than 15 Mpc for the four-kilometer interferometers, and seven Mpc for the two-kilometer interferometer." http://www.ligo.caltech.edu/~ll_news/s5_ne…

can there be a model of an expanding universe

And again, assuming that a black-hole might be the best ... visual characteristic for gravity, would it be logical to assume a ... big-bang would be the best visual opposite ... for anti-gravity? Merged post follows: Consecutive posts mergedIf it is a stupid assumption, and I need to be hit with the dummy stick, please by all means do so.

What is the speed of darkness?

Yesterday as I was walking during night, though it was cloudy,I saw that a perfect circle of clear sky formed around the moon.I was wondering that if that is some physical phenomenon or just coincidence?

I'm always a bit uncomfortable with the explanations offered regarding dark matter (and even more with dark energy, but let's save that for another thread). I know that the popular theory is that dark matter consists of particles that have little or no interactions with other particles, and that these particles are everywhere. This theory is for example explained in (warning: it's >1 hr!). In fact, it's probably explained much better than I just did . But... what I wanted to discuss: is there any proof that dark matter is not just normal matter, made of atoms? If dark matter is just normal matter (solid particles of varying size), that is relatively unifor…

I was wondering about a theory I had and was wondering if I can get any supporting evidence to assist me or to shut down the theory all together, so please if you have any imput to provide, don't hesitate. I've wondered about the existence of space for some time now, as I'm sure several people have, I was trying to learn more about stars when I came across a term "nucleus star" then I wondered, is it possible that space is I gigantic atmosphere, so enormous, that we are an electron equivalent, on a large scale atom, or some sort of variant of this?

http://www.stsci.edu/institute/conference/blackholemergers An interesting thing you immediately get if you click is eight images. Four on the left are stills from a computer simulation of a merger, calculated step by step using numerical GR methods. The four on the right are actual photographs, some with false color showing temperature, of real things which look like stages in the merger of supermassive BHs. That is, the observed thing looks somewhat like what they got by running the numerical model. This field is just getting started. Maybe at this point they don't have much more than those eight images. But I'd expect they'll be getting more interesti…