whats in between galaxies

[jasonpply]

whe looking out into space through a telescope at galaxies distant from our own we see an emptiness a black space in between im wondering if the is still a zero gravity in between these galaxies in that empty space is it possible that our solar systems version of space differs from what else is out there at the end of our solar system is a field called the heliosphere (might not be spelled correctly) i think that is where our suns gravitational pull comes to an end have any sattelites travelled this far and outside of that is there still a zero gravity effect i guess what i am asking is, is the gravitational pull of our sun possibly giving us a false sense of what space really is? beyond our heliosphere will we still be able to travel the way we do in our own solar system? or might we just drop off and fall until we catch the gravitational pull of another star or galaxie? also because beyond that we get no more heat from the sun is the temperature beyond that so low that we will never be able to go beyond? these may sound like stupid questions but im am fairly new to astronomy and am curious to hear what may be <br /> thanks in advance Jason

 

[qzzq]

It might help when you'd cut your post up in understandable sentences. <div class="Discussion_UserSignature"> <p> </p><p>***</p> </div>

 

[nexium]

Gravity does not end, but it fades away with distance, until it is negigible for most practicle purposes. The helopause and helosphere (a lumpy sphere) is where the solar wind becomes disorganized as other particles are about as numerous traveling in other directions. It is not a distinct boundry, but fades gradually like the sun's gravity fades.<br />Down is a vector of the nearby gravity fields. More often than not, one is dominent and the other fields can be ignored, for most practicle purposes. The fields weaken as the square of the distance, so no large mass, within a light year means very little gravity, speed neither increases or decreases (You coast) and you travel in a straight line. This is even more so true between galaxies.<br />In our solar system zero gravity should be called zero net gravity or free fall.<br />In the vicinity of Earth's orbit, you are typically moving about 43 kilometers per second in orbit around the sun. Lots of delta v is needed to go any other speed and direction. When there is no propulsion you fall freely at a speed and direction which causes a net gravity of zero. Acceleration due to the net gravity occurs. Accelleration can be negative = slowing down and/or accelleration can be making a turn while moving. The direction you fall is the same as the direction Earth goes around the Sun unless you are close to Earth, the moon or another body of large mass. If however you have used fuel to go a different speed and direction, that momentum is not lost (unless you crash into something). Your momentum is added vectorally to the gravity field you are in. Navigation in space is complex, so I may have erred somewhat. Neil

 

[dragon04]

I hate to say it this way because it sounds trite, but gravity is relative.<br /><br />It takes a certain velocity to escape the solar system due to the gravitational influence of our Sun.<br /><br />But it doesn't stop there. Once we leave the solar system, we may have escaped the gravitational influence of the Sun, but we now have the gravitational influence of all the stars in our "neighborhood" to deal with.<br /><br />Travelling farther out, we now have the gravitational influence of our "slice" of the galaxy to deal with. For example, I don't think the Voyager probes have enough velocity to escape the Milky Way.<br /><br />But for a moment, let's say that they do. There is a point between the Milky Way and M31 (the Andromeda Galaxy) where Voyager would begin to accelerate towards M31 due to its gravitational influence.<br /><br />Not to get too confusing, the MY and M31 are headed "towards" each other. M31 is more massive than the MW, so one could say that M31's gravity is "pulling" our galaxy (and Voyager) towards it.<br /><br />So even in the tiniest ways, gravity is always in play.<br /><br />The heliosphere isn't an accurate way to describe what you're asking.<br /><br />Basically, the heliosphere and heliopause are describing boundaries where the solar wind meets and becomes equal to the "wind" that is headed towards the Sun.<br /><br />A probe leaving our solar system gains some mechanical advantage before it hits the heliopause like a sailboat with the wind behind it.<br /><br />Once it passes the heliopause and hits the bow shock, it's like the sailboat passing from a tail wind into a head wind.<br /><br />As the sailboat approaches another star, the head wind increases, but gravity accelerates it towards the other star.<br /><br />So they're two different things. I hope I haven't confused you too much, and maybe one of our more knowledgable posters can explain it in a more simple manner than I did. <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[jasonpply]

so the heliopause/heliosphere is not our suns end of its gravitational pull. I dont know why but thats what i thought of it where the solar winds traveling near the speed of light slow drastically. iI thought the slowing was due to gravitational pull, but if i uderstand correctly you are saying it is due to another head wind. what is the head wind from? I know it cant be m31 because the heliopause is not the end of our galaxie only our solar system. I know that the voyager crafts are headed toward the heliopause quite fast (hoping to arrive by 2011) but has any others gone beyond already? <br /><br />I ask because the voyager crafts are going what looks like the long way so they can explore and return data but looking at concept drawings of our solar system and heliopause it looks like the same trip could be done in half the time simply by going up instead of across the entire span. maybe I'm wrong but thats what it looks like to me.

 

[billslugg]

jasonpply<br /><br />You harbor the misconception that gravity can end. <br /><br />Every atom everywhere in the universe exerts a gravitational attraction upon every other atom anywhere in the universe. The magnitude of the force decreases by the inverse square of the distance, but it never goes to zero. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[jasonpply]

so when they say space has a zero gravity it is a false statement?

 

[MeteorWayne]

The intention of the Voyager missions was not to leave the solar system, though it is great that they are since we are learning a lot.<br /><br />The purpose was to explore the outer members of our solar system, Jupiter, Saturn, Uranus, and Neptune.<br />After they completed those tasks, they just continued on their merry way. They will eventually leave the gravitational well of the solar system, as their speed exceeds the escape velocity.<br /><br />A mission to head "up" instead of out wouldn't leave the gravity of the sun any sooner and would take many times more fuel to set on that path.<br /><br />Wayne <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[jasonpply]

ty wayne the pics i've seen (of course none are real only drawings) show the heliopause as a long slender bubble rather than a complete circle or ball around the sun they even show it being almost next to the top of the sun guess i should do more googling but ty

 

[MeteorWayne]

Yes but the heliopause is not the end of the sun's gravity well.<br />That is a roughly ball shaped area centered on the sun, though the outer shape is determined by how close and how massive the nearest star is any any given direction.<br /><br />The heliopause is something different.<br /><br />It is the area inside of which the pressure of solar system gas caused by the solar wind matches that of the galactic gas we are traveling through.<br /><br />It is closest to the sun in the direction of our orbit around the galaxy, furthest away behind and in between above and below. <br /><br />So you are correct that the heliopause is closer above and below.<br /><br />Maybe I'm confused about what you were saying <img src="/images/icons/smile.gif" /><br /><br />Wayne <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[origin]

<font color="yellow">so when they say space has a zero gravity it is a false statement?</font><br /><br />Yes, that is an incorrect statement.<br /><br />Just like space not a perfect vacuum. It is mighty close but not perfect. <br /><br />The gravititational attraction is very very small between the galaxies but it is not zero. The gravity of our local group of galaxies is interacting. And even our local group is moving towards the virgo (I think it is virgo) super cluster of galaxies due to the gravitational attraction.<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[dragon04]

<font color="yellow">I ask because the voyager crafts are going what looks like the long way so they can explore and return data but looking at concept drawings of our solar system and heliopause it looks like the same trip could be done in half the time simply by going up instead of across the entire span. maybe I'm wrong but thats what it looks like to me.</font><br /><br />You're right on both accounts. The Voyager missions were specifically designed to observe and return data on what you could call a "tour" of the Solar System.<br /><br />New Horizons, on the other hand, is traveling at a much higher velocity (with a boost from Jupiter) to fly past Pluto.<br /><br />So, NH will get "farther faster" than the Voyagers.<br /><br />This is especially the case with Voyager 2. It traveled out on a slower trajectory so that it could visit all the outer major planets.<br /><br />The planets farther out orbit the Sun more slowly, so Voyager 2 traveled out more slowly on purpose to take advantage of the alignment of the planets to see them all.<br /><br />If Voyager 2 would have been traveling even a small fraction faster, it would have missed Saturn, Uranus, and Neptune completely.<br /><br /><font color="yellow">but if i uderstand correctly you are saying it is due to another head wind. what is the head wind from?</font><br /><br />The easiest way I can explain it would be to imagine yourself standing in your yard spraying a garden hose with a fine mist. The mist flows away from the hose (and you) with a particular force.<br /><br />Now imagine that your hose is very long, and you start running forward. The air in front of you provides more and more resistance to the mist as you run faster.<br /><br />Now imagine that additionally, there is a tiny breeze blowing towards you. The faster you run, or the harder the breeze is, the mist from your hose will go less and less far.<br /><br />That's the heliopause. The tiny breeze blowing towards you is the "wind" from particles <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[jasonpply]

awesome i get it ty all i hope they last forever data wise so we get to understand more knowledge is power

 

[usn_skwerl]

The spacectaft leaving the solar system won't last more than 50 years, even in the best of conditions. Voyager 1 and 2 wont last another 20 years. They're slowly losing power, so some systems have to be shut down as they move along. Right now, IIRC, only 8 sensors are still alive on V1.<br /><br />I'm not really sure when the others are going to die, though. <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Imterstellar space.

 

[qso1]

Intergalactic space. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>