Editing 1642: Gravitational Waves
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==Explanation== | ==Explanation== | ||
| β | [[Megan]], [[Cueball]], and [[Ponytail]] are observing the results from a {{w|gravitational wave detector}} (see [[#Gravitational waves|details below]]). This comic came out on the day that the first direct observation of gravitational waves was [http://www.nature.com/news/einstein-s-gravitational-waves-found-at-last-1.19361 publicly announced] on 2016-02-11. The {{w|Gravitational wave observation|actual event}} was recorded five months before on 2015-09-14, but it was not reported publicly before they were sure it was a real signal. It seems that [[Randall]] knew in advance about this announcement because this comic was | + | [[Megan]], [[Cueball]], and [[Ponytail]] are observing the results from a {{w|gravitational wave detector}} (see [[#Gravitational waves|details below]]). This comic came out on the day that the first direct observation of gravitational waves was [http://www.nature.com/news/einstein-s-gravitational-waves-found-at-last-1.19361 publicly announced] on 2016-02-11. The {{w|Gravitational wave observation|actual event}} was recorded five months before on 2015-09-14, but it was not reported publicly before they were sure it was a real signal. It seems that [[Randall]] knew in advance about this announcement because this comic was published on a Thursday, not following the normal publish schedule, to coincide with the [https://www.theguardian.com/science/2016/feb/11/gravitational-waves-discovery-hailed-as-breakthrough-of-the-century announcement], and there were no other comic released Friday that week. (The altered schedule could be viewed as a meta-reference to the {{w|Time warp (science fiction)|warping}} of {{w|spacetime}}.) That scientist new there might be an announcement on the way, and more details for the interested can be seen in these two videos from ''Space Time'': ''[https://www.youtube.com/watch?v=1Tstyqz2g7o Have Gravitational Waves Been Discovered?!?]'' and ''[https://www.youtube.com/watch?v=gw-i_VKd6Wo LIGO's First Detection of Gravitational Waves!]'' |
This is the second time within a month that a new astronomical announcement (of something discovered months before the actual announcement) has resulted in a related comic. The first being [[1633: Possible Undiscovered Planets]]. | This is the second time within a month that a new astronomical announcement (of something discovered months before the actual announcement) has resulted in a related comic. The first being [[1633: Possible Undiscovered Planets]]. | ||
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It is not clear if these so-called "events" are causing gravitational waves to be generated or if something, perhaps an alien civilization, is encoding spam messages in gravitational waves. It is plausible that aliens are using gravity waves to encode their messages, as we do something similar with electromagnetic waves to encode and send our messages. However, it would take an extremely advanced civilization to achieve gravity wave encoding. It requires the controlling of orbits and oscillations of super-massive bodies like the Sun, or more likely bodies ten times more massive than it. For example, the first event detected, both in this comic and in real life, was a merger of two black holes of roughly 30 solar masses each. | It is not clear if these so-called "events" are causing gravitational waves to be generated or if something, perhaps an alien civilization, is encoding spam messages in gravitational waves. It is plausible that aliens are using gravity waves to encode their messages, as we do something similar with electromagnetic waves to encode and send our messages. However, it would take an extremely advanced civilization to achieve gravity wave encoding. It requires the controlling of orbits and oscillations of super-massive bodies like the Sun, or more likely bodies ten times more massive than it. For example, the first event detected, both in this comic and in real life, was a merger of two black holes of roughly 30 solar masses each. | ||
| β | The title text makes the speculation, that something is sending spam encoded in gravity waves, seem more plausible, as it follows up with a joke that the message senders have gone to such a length that they caused the most energetic event recorded ever (perhaps on the scale of a few {{w|supernovae}} or black hole collisions). One of the scientists is so impressed with this effort that he suggests that they actually post a reply, but one of the other person declines with a "''Nah''"! (As you should always do with spam, else you will just encourage the sender by making it clear that there actually is a receiver on this address.) | + | The title text makes the speculation, that something is sending spam encoded in gravity waves, seem more plausible, as it follows up with a joke that the message senders have gone to such a length that they caused the most energetic event recorded ever (perhaps on the scale of a few {{w|supernovae}} or black hole collisions). One of the scientists is so impressed with this effort that he suggests that they actually post a reply, but one of the other person declines with a "''Nah''"! (As you should always do with spam, else you will just encourage the sender by making it clear that there actually is a receiver on this address.) |
In [[1365: Inflation]] gravitational waves are also mentioned. | In [[1365: Inflation]] gravitational waves are also mentioned. | ||
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Now, let's consider spacetime fabric as a thin rubber sheet. If you mark any two points on this sheet and stretch or compress it along the axis joining those two points, the relative positions of these points with respect to their neighboring points do not change, but the distance between them changes. | Now, let's consider spacetime fabric as a thin rubber sheet. If you mark any two points on this sheet and stretch or compress it along the axis joining those two points, the relative positions of these points with respect to their neighboring points do not change, but the distance between them changes. | ||
| β | {{w|LIGO}} (Laser Interferometer Gravitational-Wave Observatory) is a large-scale physics experiment designed to detect this compression/expansion, and it was LIGO who discovered the signal that caused this comic | + | {{w|LIGO}} (Laser Interferometer Gravitational-Wave Observatory) is a large-scale physics experiment designed to detect this compression/expansion, and it was LIGO who discovered the signal that caused this comic. |
Two facts need to be remembered to easily understand the experiment. First, the {{w|speed of light}} (c) is constant and the speed of an object is the distance moved divided by the time taken to travel that far. Second, gravitational waves cause opposite effects (compression and expansion) in directions perpendicular to each other. At LIGO, an experiment is set up where two perpendicular long tunnels are constructed with apparatus to emit and detect laser beams. The beam from a laser is split into these two tunnels. After going through the tunnel and back again a few times the beams are brought back together. The lengths of the tunnels are set up in such a way that, in the absence of gravity waves, destructive interference between the two combined beams causes them to cancel one another out, resulting in the detector observing zero light intensity. When the gravitational wave passes through earth, one of the tunnel is expected to expand while the other is expected to compress. Due to the difference in lengths, the destructive interference is incomplete and the detectors will be able to detect the presence of light. This observation can be concluded as "detection of the gravitational wave passing through". | Two facts need to be remembered to easily understand the experiment. First, the {{w|speed of light}} (c) is constant and the speed of an object is the distance moved divided by the time taken to travel that far. Second, gravitational waves cause opposite effects (compression and expansion) in directions perpendicular to each other. At LIGO, an experiment is set up where two perpendicular long tunnels are constructed with apparatus to emit and detect laser beams. The beam from a laser is split into these two tunnels. After going through the tunnel and back again a few times the beams are brought back together. The lengths of the tunnels are set up in such a way that, in the absence of gravity waves, destructive interference between the two combined beams causes them to cancel one another out, resulting in the detector observing zero light intensity. When the gravitational wave passes through earth, one of the tunnel is expected to expand while the other is expected to compress. Due to the difference in lengths, the destructive interference is incomplete and the detectors will be able to detect the presence of light. This observation can be concluded as "detection of the gravitational wave passing through". | ||
