tag:blogger.com,1999:blog-6052690275993145605.post5470419127740632133..comments2023-10-01T01:38:30.606-07:00Comments on Journey By Starlight: Relatively simple. An easy guide to relativityalbert2.0http://www.blogger.com/profile/04102932927469813620noreply@blogger.comBlogger18125tag:blogger.com,1999:blog-6052690275993145605.post-12252736482359813252010-01-22T13:29:25.711-08:002010-01-22T13:29:25.711-08:00The two types of relativity are special relativity...The two types of relativity are special relativity and general relativity. Special relativity deals with things moving at a constant speed, like light or trains or cars and general relativity deals with gravity. Space is curved and if you travel far enough in a straight line you will end up back in the same place.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-10053455270439890502009-05-08T20:20:00.000-07:002009-05-08T20:20:00.000-07:00Anonymous said...
Come on Albert, don't you k...Anonymous said...<br /><br /> Come on Albert, don't you know that it is far easier for people to read black on white, and difficult to read white on black? I wanted to join, but I cannot stand the strain on my eyes... I will come back later... and if it changes to black on white for easier reading I will join in the blogs.<br /> Sincerely,<br /> Allan Hansford<br /><br />Solution:<br /><br />Highlight the text and you have dark text on white background.<br /><br />Thanks albert 2.0 for the workdarthcricketnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-50585749741627735672009-02-17T15:27:00.000-08:002009-02-17T15:27:00.000-08:00Have a look at this posting:http://journeybystarli...Have a look at this posting:<BR/>http://journeybystarlight.blogspot.com/2007/10/seasons-ice-ages-and-why-greenhouse.html<BR/><BR/>Without the tilt there wouldn't be seasons but without the earth orbiting the sun the "seasons" wouldn't change.albert2.0https://www.blogger.com/profile/04102932927469813620noreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-6254136128278534052009-02-17T09:47:00.000-08:002009-02-17T09:47:00.000-08:00you stated that the seasons occur because of our o...you stated that the seasons occur because of our orbit around the sun.<BR/>The seasons actually occur due to the tilt of the earth ( about 23 degrees)the orbit of the earth around our star has very little effect if any as we are in a nearly circular orbital patternAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-23134074800146437432009-02-05T16:22:00.000-08:002009-02-05T16:22:00.000-08:00First of all thank you for your blog. I found it v...First of all thank you for your blog. I found it very useful as it was explained in a very easy and understable way. <BR/><BR/>The thing I don't understand is that why mass of an object must increase with its speed. I know that if a big object travels faster or in the speed of light its mass becomes infinite. But why?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-21156913358923202362009-01-20T13:47:00.000-08:002009-01-20T13:47:00.000-08:00If photons can never be stopped to be examined the...If photons can never be stopped to be examined then where do they come from orginally?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-57190007339771590722008-12-12T01:15:00.000-08:002008-12-12T01:15:00.000-08:00Good question, David. The trick to understanding t...Good question, David. The trick to understanding the expansion of the universe is to realize and accept that there is no dimensional "direction" of the universe's expansion, nor is there a physical "center" of the universe. Imagine for a moment that our round Earth were expanding. Would this mean that there must be a "center" of the Earth's <I>surface?</I> The Universe's expansion is measured in the direction of time we call the past, not in a physical dimension of space. The idea which someone else posed helped me understand this is: imagine that the universe is on the surface of a balloon, which is being filled with air. Take an uninflated balloon, and make dots on it with an ink pen. Now inflate the balloon. You will notice that, as the balloon gets larger, all the dots get further apart. Is there a center or edge of the balloon's surface? No. The only center is in the past, a direction backward in time. Is there an edge of space? No, there is only a future larger size. And as Albert said, if you were to travel in any direction far enough, you would come full circle, as you would if travelling around the world. Imagine what our ancestors thought back when the Earth was believed to be flat, and you will understand the challenge of seeing both perspectives. We now take for granted that the Earth is round; The next step is to accept that space is also curved. We can travel indefinitely in any direction on the surface of the Earth and never percieve that we aren't going in a straight line, but a curved one. The same applies to traveling through space.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-75130720413019932972008-05-02T07:50:00.000-07:002008-05-02T07:50:00.000-07:00If everything in the universe is traveling, thus m...If everything in the universe is traveling, thus making everything relative in time as well as space, shouldn't the speed of light also be relative? Light would seem to be moving faster if slower in the same direction as the universe is expanding; however, if moving toward the center of the universe (away from the expansion), the light would appear to be moving faster.Davidhttps://www.blogger.com/profile/09000587223485229539noreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-71728926563768804292007-08-30T07:13:00.000-07:002007-08-30T07:13:00.000-07:00I know that light travels slower in different medi...I know that light travels slower in different mediums, but is there any theory (perhaps yours) that predicts if the speed of a graviton travels slower in a different medium? Or is there just not enough evidence to support a suggestion like that for this elusive particle?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-36491028278974592212007-08-29T15:37:00.000-07:002007-08-29T15:37:00.000-07:00Quite right, the effect of gravity would spread ou...Quite right, the effect of gravity would spread out as a wave so it normally wouldn't catch-up! Could a gravity wave overtake a light wave?<BR/>Yes if the light wasn't travelling directly away from gravity source. It<BR/>could also catch up if the light were travelling through a material (like water) that slowed it down more than gravity waves.albert2.0https://www.blogger.com/profile/04102932927469813620noreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-9328418521127658792007-08-28T14:39:00.000-07:002007-08-28T14:39:00.000-07:00Getting to the original question, where light is e...Getting to the original question, where light is emitted from a point, and then seconds later that point turns into a point of extreme gravity, like a black hole: NOTHING WOULD HAPPEN. Gravity waves travel at the speed of light. Since the light emitted from the original point already had a head start, the warping of the newly formed black hole would not catch up to the original beam. <BR/><BR/>Please someone correct me if I am wrong, but Einstein, you yourself showed that gravity waves move at light speed: If the sun dissapeared we would see it and feel it at the same time. The earth would not be shaken, then 8 minutes later the sun flickers off.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-38272576307167443782007-07-13T07:53:00.000-07:002007-07-13T07:53:00.000-07:00Well, its not constant as it slows in glass water ...Well, its not constant as it slows in glass water and most other things, but it is constant in space at least in terms of metres per second. Why? Because the metre is now definfed in terms of the speed of light. Any real change now in the speed of light will change the length of a standard metre instead.albert2.0https://www.blogger.com/profile/04102932927469813620noreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-86882917544142204222007-07-13T03:40:00.000-07:002007-07-13T03:40:00.000-07:00I've read numerous accounts of people saying that ...I've read numerous accounts of people saying that the speed of light is actually not a constant. They have been measuring it over the years and the speed of light is degrading just like everything in the universe. What kind of impact does that have on your theories?Toddhttps://www.blogger.com/profile/11400973228669038318noreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-27262886143455759982007-07-08T03:51:00.000-07:002007-07-08T03:51:00.000-07:00Sorry you found black a problem. It's a big proble...Sorry you found black a problem. It's a big problem out here in space. Everything is pretty black.albert2.0https://www.blogger.com/profile/04102932927469813620noreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-5766107501776202922007-07-07T13:03:00.000-07:002007-07-07T13:03:00.000-07:00Come on Albert, don't you know that it is far easi...Come on Albert, don't you know that it is far easier for people to read black on white, and difficult to read white on black? I wanted to join, but I cannot stand the strain on my eyes... I will come back later... and if it changes to black on white for easier reading I will join in the blogs.<BR/>Sincerely,<BR/>Allan HansfordAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-71026494480366408822007-07-05T12:00:00.000-07:002007-07-05T12:00:00.000-07:00So, if I understand correctly, if you "stop" light...So, if I understand correctly, if you "stop" light it disappear... <BR/><BR/>Unless you manage to slow down time, and "trap" the photons... from a outsider point of view, because to light, all is normal an traveling at normal speed.<BR/><BR/>shesss... so Light is really a constant, for what I understand, it just cannot exist if is not moving at what is supposed to.<BR/><BR/><I>If the gravity source is rotating, like most black holes, the light will also seem to spiral away rather than move in a straight line. Strange huh?</I><BR/><BR/>Why?<BR/>The black hole is twisting the time and space so much?<BR/><BR/>I love this stuff, is so good for the brain.<BR/><BR/>And just as a side note, I found your site thanks to your interview in TWIS.Dodohttps://www.blogger.com/profile/09825743395748117816noreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-61708179810161452182007-07-05T02:47:00.000-07:002007-07-05T02:47:00.000-07:00Great question. If gravity is strong enough to "st...Great question. If gravity is strong enough to "stop" light you would have to be within Schwarzchild radius, so it will be trapped and just disappear from the visible universe. If it is just outside that distance it will escape but strange things will happen if the gravity is very strong.<BR/><BR/>What will be seen from a distance is that the colour of the light will shift to the red which is the gravitational version of the red shift. Something we'll cover next time is the effect of speed and gravity on time. Time will slow down near the gravity source, so it will take a longer time to escape even though it is still moving at the speed of light if you measure it at that point. Just at the point of disappearing in the black hole or escaping it will seem to take an infinte amount of time to escape. If the gravity source is rotating, like most black holes, the light will also seem to spiral away rather than move in a straight line Strange huh?albert2.0https://www.blogger.com/profile/04102932927469813620noreply@blogger.comtag:blogger.com,1999:blog-6052690275993145605.post-71841127202193586442007-07-04T13:12:00.000-07:002007-07-04T13:12:00.000-07:00Fantastic Blog, I'm enjoying every post.Clear and ...Fantastic Blog, I'm enjoying every post.<BR/>Clear and fun, it reminds me of Carl Sagan's "Cosmos". <BR/><BR/>About light speed, I have a question:<BR/>It's velocity is an absolute, it starts at it, there is not acceleration (and that is so weird), so when reading I had an idea...<BR/><BR/>Light can be affected by gravity, if is strong enough it bends and change paths, and in a Black Hole it can't escape so what happens if -using our imaginations- a light beam is emitted from a point, and after some seconds the point of origin transforms in a gravity source really strong.<BR/><BR/>What is going to happen?<BR/><BR/>If is strong enough, it should affect the light... will it make stop and reverse direction, now towards the gravity source?<BR/>And if that happens, it will first decelerate to zero and then reverse, or will it just flip directions? <BR/><BR/>Maybe a gravity source so strong is not possible, but well...<BR/><BR/>Keep writing!Dodohttps://www.blogger.com/profile/09825743395748117816noreply@blogger.com