Interstellar Definition and 134 Threads

  1. C

    Time Dilation Paradox: Interstellar Race

    Hi, I asked a theoretical question here a month or two ago and someone was able to help me. I have another: Imagine an interstellar race. Starship 1 heads from Earth toward Alpha Centauri at a constant rate close to the speed of light, then makes a loop and returns home. Ship 2 is faster, and...
  2. B

    Force on Planet Moving in Interstellar Dust

    Homework Statement A uniform, spherical planet of mass M and radius R moves SLOWLY with an essentially uniform speed v through a cloud of interstellar dust particles, whose density is ρ. The dust particles are attracted towards the planet, and some of them would eventually fall onto its...
  3. A

    Astronomy - interstellar dust grains

    Homework Statement A typical dust grain has a radius of 10-7 m and a mass of 10-14 g. How many dust particles are there in a molecular cloud containing 1000*Masssun of dusty gas if 1% of the cloud's mass is in the form of dust grains? Homework Equations The Attempt at a Solution...
  4. S

    What are the limits of interstellar travel?

    For simplicity consider an unmanned probe to a star in our neighbourhood say 10 to 20 LY. Most discussions of this concentrate on speed and power. But what is the fastest realistic velocity? 40,000 MPH (~ 1/10 of 1% of light speed)? Even at this speed interstellar dust banging away at the...
  5. R

    Could Solar Energy Beams Enable Interstellar Travel?

    Ever since I saw stephen hawkings universe doc's, I've been wondering about one creative scenario he presented. surround our sun with solar energy satellites. Draw and store the energy in the satellites. satellites fire this energy in beams (synchronized) into one satellite which then...
  6. R

    Length contraction and interstellar travel

    Interstellar travel is always a problem in science fiction: you can't have the hero hibernate for millions of years whenever he or she wants to travel to another star, but it's annoying when spaceships just magically move faster than light. However, wouldn't length contraction from special...
  7. J

    Time Dilation and Future Interstellar Travel

    Hello all, I am new to the Forum and have no formal Physics training. I have an interest in the subject mainly due to other pursuits. I am reading Joe Haldeman's The Forever War. I would definitely recommend this book to anyone with an interest in Time Dilation or Humans vs Aliens at...
  8. W

    Retarded Force in Space and interstellar dust

    Homework Statement A uniform, spherical planet of mass M and radius R moves SLOWLY with an essentially uniform speed v through a cloud of interstellar dust particles, whose density is ρ. The dust particles are attracted towards the planet, and some of them would eventually fall onto its...
  9. T

    Interstellar Gas & Dust, Densities & Temperatures

    Howdie. This question started from what was to be a "simple" analysis of heating the air in a room. So much for simplicity when you start to question what exactly is heat and what is happening to atoms and molecules. SOOOO...the question I have (which will have bearing on my INITIAL quest)...
  10. B

    The beautiful sight of the interstellar traveller

    Hi, I'm new to SR and GR in general. In fact, I just discovered Lorentz equations a week ago. And that got me thinking too, just as it must have happened to you too. I like maths, but I'm more the kind of artistic person. And I was wondering what would be the sight of a traveller, on board...
  11. K

    How Long Does an Interstellar Cloud Take to Contract?

    Problem:"An interstellar cloud with a radius of 10parsecs and a mass of 10000 Msun is contracting. How long does this take? (The cloud itself has no pressure)
  12. wolram

    Possibility of affordable interstellar space flight

    This is an old paper but at least it is a start for a discussion on the affordability of interstellar travel. http://www.andrews-space.com/images/videos/PAPERS/Pub-InterstellarTransportation(200307).pdf If one uses some marker for a nations, or a group of nations wealth, will...
  13. U

    Interstellar TV: Calculating Detection Range

    I am just "trying" to watch interstellar TV... The detection range in lightyears is R = \sqrt{\frac{\text{EIRP}\cdot A_{e}_{r}\cdot\text{twc}}{4\pi\cdot\text{SNR}\cdot B_{r}\cdot k_{B}\cdot T_{sys}}}\cdot\frac{1\,\text{ly}}{9454254955488000\,\text{m}}, where \text{EIRP} = P_{t}G_{t}...
  14. U

    Should we send interstellar probe to Alpha Centauri?

    Should we send an interstellar (unmanned) probe to Alpha Centauri? Would it be much more expensive than a manned mission to Mars? According to Wikipedia, velocities as high as 0.10c are possible with hydrogen bombs. That means that ~40 years flight time to the nearest star would be possible...
  15. O

    On GR and Interstellar exploration

    Hello folks, I was wondering about a possible probe sent to alpha centauri which would be able to do a deep scan of the system, maybe for a month, and then send back results. I then wondered, that if the probe was exposed to different gravitational conditions, let's say favourbly, would...
  16. matthyaouw

    Is This the Future of Space Communication?

    click me If this were april first, I'd dismiss this in the blink of an eye :confused: While I'm not against the idea as such, what kind of first impression about our species would this give anyone who does receive it on the other end?
  17. S

    Interstellar space travel and reference frames

    Homework Statement A spacecraft with its astronaut has a total mass at rest of 10^5 kg. The astronaut is to travel to a star 10 light years away at a speed such that she only ages 1 year in her frame of reference a) the quantity 1-v/c where v is her speed with respect to Earth is? b)...
  18. G

    Compute the main free path of a hydrogen atom in interstellar space

    Problem: Interstellar space has an average temperature of about 10K and an average density of hydrogen atoms of about one hydrogen atom per cubic meter. Compute the main free path of a hydrogen atom in interstellar space. Take the diameter of an H atom to be 100 pm. Here is what I did. I...
  19. R

    Does Interstellar Extinction Change the Angular Size of Star Clusters?

    The presence of interstellar extinction makes stars appear dimmer and appear more “distant” than they truly are. (This is true for individual stars and for clusters of stars). Does dust affect the observed angular size of a star cluster (assuming the distribution of the dust is smooth)? That...
  20. O

    Miniprobes for interstellar exploration

    I know it would take an obscene amount of energy to put any type of manned spaceship within reach of neighboring stars... but why can't tiny probes, maybe the size of a baseball, or if necessary a marble, be sent instead? Say we explode a nuke to fling a few of these 'spaceballs' towards Proxima...
  21. R

    Interstellar Dust: Extinction & Photon Ratio

    Homework Statement Suppose that the density of interstellar dust is uniform along the direction of the plane of the galaxy, but that its vertical density is given approximately by \rho = \rho \o exp - ( z / 0.15 )^2 where z is the distance from the plane of our galaxy in kpc. If the...
  22. P

    Interstellar Medium: Est. Mean Mass of Particle

    Hey, can anybody tell me what the estimate is on the mean mass of a particle in the interstellar medium? I would guess around 1-10 proton masses?
  23. vincentm

    Difficulties with interstellar travel

    According to Relativity, if a ship traveling at nearly the speed of light through interstellar space diffuse atoms (mostly Hydrogen, becase simply that is the most abundant atom in the universe, right?) would strike the front of the ship with increased mass, causing radiation. My question is how...
  24. C

    Interstellar Medium: Herbig-Haro Objects

    Hi all. First post and all that, so I hope I don't do anything wrong, and that if I do, you'll cut me a little slack :P Anyway, onto the question I'm wanting help with: A J-shock in a Herbig-Haro object is propagating through neutral hydrogen gas at speed 100km/s. The gas has number...
  25. L

    Interstellar Travel: Theorical Force to Stabilize Wormhole

    Theorically speaking, what force could stabilize a wormhole?
  26. C

    Solving Interstellar Gas Pressure: A Daunting Task

    I have been trying to do this questions for about 30 minutes right now and its a one dot questions. I think I am converting the atoms wrong. Could someone help me? A typical region of interstellar space may contain 10^6 atoms per cubic meter (primarily hydrogen) at a temp of 100 K. What is...
  27. C

    Oort Cloud Treat to Interstellar Space Travel

    A few quotes from various sources suggest there is quite a bit of material in the Oort Cloud, maybe enough to threaten interstellar space travel: “The Oort cloud is an immense spherical cloud surrounding the planetary system and extending approximately 3 light years, about 30 trillion...
  28. E

    Interstellar propulsion island hopping the Oort cloud

    Ahad's virtual bridge might have to charge a toll fee: http://www.astroscience.org/abdul-ahad/firstarktoalphacentauri/interstellar-propulsion.htm :!)
  29. H

    Interstellar medium: Theory and models.

    I am trying to get a basic understanding of the physics of the interstellar medium and the current models which describe it (FGH and McKee-Ostriker). A first question arises regarding the possible assumption of a gas in ionization equilibrium, in which ionizarion and recombination occur at...
  30. P

    Relativity interstellar travel question

    well the textbook question is (transfer me over to hmwk help its ok) 2 Civilizations are evolving on oppposite sides of our galaxy (d = 10^5 ly) at time t = 0 in the galaxy frame of reference, civilization A launches its first intersteller spacecraft , 50,000 years later, measured in the...
  31. M

    Interstellar Gas Cloud: High Temp Mystery

    http://science.nasa.gov/headlines/y2004/27sep_shieldsup.htm?aol667632 At the above link, it appears there is a high temperature cloud of gas has been colliding with the solar system. What could keep a cloud of gas at such a high temperature in the interstellar medium?
  32. Norman

    Interstellar Medium and Pulsars

    Originally posted in College Level Homework help but I got no responses there. Please help if you can. I am studying for my qualifier and doing problems out of Jackson. I am stuck on this one... any help would really be appreciated... I am unsure how to begin: Jackson 7.15 The partially...
  33. B

    Interstellar Travel: Reaching Alpha Centauri

    How long will it be before we reach alpha centauri, i was on a thread on Fark.com yesterday about going to Mars and it interstellar travel came up. I figured you guys (and girls) would prob have a better idea on what ideas are out there right now. this was my post: do you know how impossibly...
  34. T

    Is Interstellar Travel Feasible with Current Physics?

    (read *lost* in general discussion- thought itd be better if i posted this again here) interstellar travel. i wanted to know the possibility of it actually being able to happen. iv got coursework to do, and it can be on anything we want it to be on, as long as its got summat to do with...
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