Star Definition and 1000 Threads

Homework Statement A neutron star has a mass of 2.0 x 1030 and a radius of 5.0 x 103. Suppose an object falls from rest near the surface of the star. How fast would it be moving after it had fallen a distance of 0.010 m? (Assume that the gravitational force is constant over the distance of the...

I was reading some articles on the internet, about scientists being able create space ships capable of nearing the speed of light, some time in the future. So say they did do this and managed to reach around 0.9999999% of the speed of light and wanted to travel to the nearest star which, to keep...

The mass of a star is 1.4 × 10^31 kg and it performs one rotation in 26.3 day. Find its new period if the diameter suddenly shrinks to 0.55 times its present size. Assume a uniform mass distribution before and after. I don't know what I am doing wrong here: Iw(intial)=Iw(final)...

The laser is able to vaporize an Earth sized planet in about a second.

This is the first time I am posting here. I thought I whould show this website as a way to introduce myself. I'm interested in anything dealing with science, especially cosmology. I have always liked showing this website to everyone because it really shows how small we are...

[SOLVED] Binary star system and Apparent magnatudes I was asked this questing in my tetbook and can't figure out how to do it. Suppose there is a binary system made up of two identical stars, each with an apparent magnitude of +4.1. However, from our 40 cm telescope they appear as one star...

The mass of a star is 1.170×1031 kg and it performs one rotation in 28.30 day. Find its new period (in days) if the diameter suddenly shrinks to 0.610 times its present size. Assume a uniform mass distribution before and after. How do I even start this problem? Can anyone give me step by...

I'm a writer working on my first novel. The genre is science fiction and I'm trying to keep the science part of it as close to the realm of possibility as I can. The setting is in a smaller system about 10 to 50 light years of our system. Can someone name a star and its location that is of...

Homework Statement A certain triple-star system consists of two stars, each of mass m = 7.00×1024kg, revolving about a central star of mass M = 1.69×1030kg in the same circular orbit of radius r = 2.00×1011m(see the figure). The two stars are always at opposite ends of a diameter of the...

http://www.stuff.co.nz/4426392a10.html Is this for real? I am somewhat sceptical of anything of a technical or scietific field that I read in the mass media.

Hey all, I need a help to determine the Mass-Radius relationship for a neutron star. I've done it for a white dwarf, but for a neutron star I need to know the Neutron degeneracy pressure expression, can anyone please help me to solve it? I am thinking that if I have the n.deg.pressure...

An object orbits a star, both items comprise the system. I am looking for confirmation of a couple of concepts regarding orbits. As the object slows down, does the kinetic energy of the system decrease, and does the total energy of the system decrease? As the kinetic energy of the system...

Is there a simple-model equation for the radial density of a neutron star, from core to shell? I assume there have been models of fermionic gases, anyone have something onhand Is it a specific distribution? Linear? 1/r^2? I know its just a balancing of gravitational potential with strong...

Recall in Star Trek the next generation and of the new series, they use replicators and holodecks. Many science degrees work hard in all fields of knowledge. In the future technology will mature and that kind of science may be real. How do you think society will react this scientific...

I am looking for a general approach for a type of problems as follows... Certain circumpolar star has a maximum azimuth A given for example as an angle from North to East and from North to West. Whats the declination of that star? The problem looks like this: draw a celestial sphere and...

Looks way more fun than what I've been doing... http://www.theage.com.au/news/national/now-for-star-treks-enterprising-thesis/2006/08/27/1156617211732.html

[SOLVED] Apparent magnitude of binary star? Homework Statement A binary star has a total apparent magnitude of 15.00. One component star is twice as bright as the other. a) Show that the apparent magnitude of the brighter star is 15.44. b) The fainter star has an apparent magnitude of...

Right I've got an exam at half past 4, tomorrow on a Saturday! I've spent the past few days doing past exam questions and a lot of them I'm able to do or at least work out for myself after a bit of time. Here's a couple I'm really stuck on so some help would be really really appreciated...

[SOLVED] Density of a star Homework Statement For a star of mass M and radius R, the density increases from the centre to the surface as a function of radial distance r, according to \rho = \rho_{c}[1-(\frac{r}{R})^2] where \rho_{c} is the central density constant. a) Find M(r). b)...

The Chandrasekhar limit (~1.4 Msolar) is an upper limit to the mass a white dwarf star. So this means we can not have a white dwarf star in nature that weighs more than this. But is it true that we can have a neutron star that weighs less than 1.4 Msolar? If so, this makes no sense to me...

Homework Statement Consider a double-star system with two stars, A and B, in circular orbits of the same period T about their center of mass. The Earth is in the plane defined by these orbits at a distance R of many light-years. Let the speed of A in its orbit be u; then at any instant it has...

Hello, several nights ago I was outside looking at the sky. I noticed this strange looking star near the horizon, and I swear to you, it kept flashing from red to blue and back. I vaguely remember reading something about this, but I don't quite remember what it was.

Hi all, I'm wondering why we see those horizontal and vertical stripes of lights when looking at a light source (see e.g. http://apod.nasa.gov/apod/image/0601/pleiades_gendler_big.jpg" ). Why are these lines of light present in the first place and why are they only horizontal and vertical in...

Wow, From current experiments and theory; the idea of a cloaking device may be a reality. This leads me to the question; is there research in other areas of the so called "Star trek Physics" i.e. force fields etc?

I was flipping through the channels this evening and came across an old Star Trek (original series) episode. Since I hadn't seen one in while (It is shown at 10pm, and lately I've had to get up early Sun AM, and I am in bed by then), I decided to watch it. I had just recently purchased a...

When a star explodes, does the shock wave move faster than the local speed of light? If it does, what effects would this have? A little explaining is in order... While the actual speed of light does not change (c in a vacuum) the overall progression of light is greatly slowed down due to...

http://www.nasa.gov/centers/goddard/news/topstory/2007/intergalatic_shot.html Solid proof that aliens are about, this must have been a warp core breach.

Homework Statement Two equal-mass stars maintain a constant distance apart of 8.0 x10^10 m and rotate about a point midway between them at a rate of one revolution every 12.6 yr (a) why don't the two stars crash into one another due to the gravitational force between them (b) what must be...

Neutron stars are extremely dense objects with a mass comparable to the mass of the sun but a radius of only several thousand meters. Consider a neutron star of mass M = 1.99e+030 kg and a radius of R = 10.8 km. What is the gravitational acceleration near the surface of the star? I tried...

I'm having trouble solving this question... If the epsilon ring of Uranus is 75 km wide, how long will it occult a star? Any help would be greatly appreciated.

If star clusters were all about the same physics size, how could one estimate their relative distances?

Homework Statement An empty bucket (mass M, area A) is launched with velocity v0 from a space station into a cloud of dust (density ρ). As the bucket moves through the dust it will collect dust in it until the bucket comes to a stop. Solve the place of the bucket x=x(t). 2. The attempt at a...

Hi! I have a project where I am supposed to model the s-process in a star in its Helium shell burning region, and i shall do this for a variation of neutron exposure, where neutron exposure are defined as: \tau = N* \Delta t , t is time. N is number density of neutrons. So I in...

Homework Statement Under some circumstances, a star can collapse into an extremely dense object made mostly of neutrons and called a neutron star. The density of a neutron star is roughly 10^{14} times as great as that of ordinary solid matter. Suppose we represent the star as a uniform...

Homework Statement Say you have a binary star sytem. Both stars have mass M and semimajor axis a. The orbits are extremely eccentric (e is approximately 1). How would you describe the energy of the system? Homework Equations SEE BELOW The Attempt at a Solution Basically I'm very...

Homework Statement Neutron stars, such as the one at the center of the Crab Nebula, have about the same mass as our sun but a much smaller diameter. If you weigh 675 N on the earth, what would be your weight on the surface of a neutron star that has the same mass as our sun and a diameter...

What is the estimated value of the local star formation rate (SFR) and how accurately do we know this number?

[b]1. After a collapsing star decreases its radius to half its initial size, predict what will happen to its angular velocity(Assume uniform density at all times)Your answer describes the high angular speed of neutron stars. Find the change in the rotational kinetic energy of the star. Where...

Homework Statement I need to know how to calculate the temperature of a star from it's B-V color Homework Equations B = -2.5log(F440)+C V = -2.5log(F550)+C B-V = -2.5log(F440/F550) The Attempt at a Solution Really no idea, all my textbooks say that B-V color is used to...

Homework Statement One of the most prominent spectral lines of hydrogen is H_\alpha line.A bright red light with wavelength of 656.1\times 10^{-9}m.What's the expected wavelength of the H_\alpha line from a star receding with a speed of 3000 km/s? The Attempt at a Solution Is...

A recent (dumb) question that came to mind. Perhaps I posted in the wrong place recently. Given the brightest known star. What is the maximum distance we would be able to see it given current technology. Is there a rule or something? Say the divergence of photons vs initial brightness...

Period of a Star...Please help! Homework Statement The mass of a star is 1.250×1031 kg and it performs one rotation in 36.30 day. Find its new period (in days) if the diameter suddenly shrinks to 0.590 times its present size. Assume a uniform mass distribution before and after. I don't...

A star has a mass approximately 100 times that of our sun. If a planet with the same mass as the Earth is oribiting at a radius similar to that of the Earth's radius around the sun, how long would it take the planet to revolve around the star once? Ok, the period of the Earth's rotation is...

Does anybody have any idea how to solve this problem: The extinction of light due to its passage through a partially opaque medium is given by Beer’s Law (known by most chemistry students and many physics students, I hope!): I = Io e^ T where (Io) is the intensity of the light...

iI was asked to find the mass of a star given the orbital distance and the period. my mass came out to be 2.31^30 kg. Its then asking me to express it in terms of our sun's mass. Really don't understand what it means by that

1. Homework Statement Determine the apparent magnitude difference between sirius and the sun,as seen from the Earth. How much more luminosity is sirius than the Sun ? 2. Homework Equations f=sigma*T^4(eff) m-n=2.5*log(f(m)/f(n)) 3. The Attempt at a Solution the apparent...

Homework Statement A variable star changes in brightness by a factor of 4. What is the change in magnitude?Homework Equations m and n represent two stars of magnitude m-n=2.5 log(f(n)/f(m)) log (f(n)/f(m))=.4*(m-n) The Attempt at a Solution I think m-n is suppose to represent a change in...

Field of Eschatology pertaining to the binary star "Wormwood" Doe sanyone have any information of the binary star "Wormwood" can they offer any insight as to how it coinsides with the book of Revelation chapter 8

http://science.nasa.gov/headlines/y2007/15aug_mira.htm?list213022 Audio http://science.nasa.gov/headlines/y2007/images/mira/audio/story.m3u

Sun is an "ordinary" star I've read in different books the Sun is an "ordinary" star, and an "atypical" star. Anyone know which description is the correct one?