2079: Alpha Centauri - Revision history

172.71.123.114: Removed two spaces that affected nothing.

2024-04-29T15:50:09Z

Removed two spaces that affected nothing.

ChristmasGospel: Edit by ClassicalGames

2023-05-09T07:20:12Z

Edit by ClassicalGames

172.70.162.56: Undo revision 303583 by SilverTheTerribleMathematician (talk) It's more correct to talk of "(¿the rest of?) the Alpha Centauri system" than not...

2022-12-28T11:41:02Z

Undo revision 303583 by SilverTheTerribleMathematician (talk) It's more correct to talk of "(¿the rest of?) the Alpha Centauri system" than not...

SilverTheTerribleMathematician: /* Explanation */

2022-12-28T04:54:47Z

‎Explanation

SilverTheTerribleMathematician: /* Star Rating Systems */

2022-12-28T04:51:39Z

‎Star Rating Systems

JLZ0kTC5 at 09:59, 21 October 2022

2022-10-21T09:59:18Z

Jacky720: Reverted edits by Xray Kilo Charlie Delta (talk) to last revision by Davidy22

2022-05-23T18:44:58Z

Reverted edits by Xray Kilo Charlie Delta (talk) to last revision by Davidy22

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Xray Kilo Charlie Delta: haha your js cant stop my js

2022-05-23T18:12:35Z

haha your js cant stop my js

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Davidy22: Reverted edits by Explain xkcd server admin (talk) to last revision by Theusaf

2022-05-21T02:55:43Z

Reverted edits by Explain xkcd server admin (talk) to last revision by Theusaf

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Explain xkcd server admin at 21:39, 20 May 2022

2022-05-20T21:39:01Z

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 Top Speed: 75,000,000 m/s ~ 1/4*c.
 Assuming E = F*d, 0.136*1*4.13e+16 = 5.37e15 Joules will be required for each kilogram carried to Alpha Centauri in 35 years.
 This would require an unimaginable amount of mass for a conventional chemical rocket, and is a completely impractical power requirement for any sort of passive solar sail concept.

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 ===Star Rating Systems===
-Online rating systems, such as {{w|Yelp}}, often use {{w|Star (classification)|star rating system}}s, with more stars indicating higher quality, up to an arbitrary maximum, such as five stars to indicate the best rating. Due to the nature of 5 star rating systems, as shown in in comic [[1098: Star Ratings]], anything scoring less than 4 out of 5 in a 5 star rating system is crap; and in a 10-star rating system, scoring a mere 3 stars out of a possible 10 stars would be ''exceedingly'' low quality. The Alpha Centauri star system has 3 ''physical'' {{w|star}}s: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. The offscreen person has misconstrued this fact of the system as some kind of review.
+Online rating systems, such as {{w|Yelp}}, often use {{w|Star (classification)|star rating system}}s, with more stars indicating higher quality, up to an arbitrary maximum, such as five stars to indicate the best rating. Due to the nature of 5 star rating systems, as shown in the comic [[1098: Star Ratings]], anything scoring less than 4 out of 5 in a 5 star rating system is crap; and in a 10-star rating system, scoring a mere 3 stars out of a possible 10 stars would be ''exceedingly'' low quality. The Alpha Centauri star system has 3 ''physical'' {{w|star}}s: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. The offscreen person has misconstrued this fact of the system as some kind of review.
 The title text furthers the pun. Some online star rating systems also allow partial stars, such as a half-star, to allow more precision in rating (e.g. rating 2.5 stars instead of being forced to chose 3 stars or 2 stars), or display an average collective rating as partial stars (e.g. showing 2.5 stars when five people have rated 3 stars and five people have rated 2 stars). Alpha Centauri's "half star" refers to Proxima Centauri, a {{w|red dwarf}}, which is a type of low-mass star. According to the offscreen person, this barely qualifies it to be a star. Furthermore, Proxima Centauri is nearly 13,000 AU (0.21 light years) away from the other 2 stars in the system, so it was long unknown whether Proxima Centauri was gravitationally bound to the Alpha Centauri star system.

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 Online rating systems, such as {{w|Yelp}}, often use {{w|Star (classification)|star rating system}}s, with more stars indicating higher quality, up to an arbitrary maximum, such as five stars to indicate the best rating. Due to the nature of 5 star rating systems, as shown in in comic [[1098: Star Ratings]], anything scoring less than 4 out of 5 in a 5 star rating system is crap; and in a 10-star rating system, scoring a mere 3 stars out of a possible 10 stars would be ''exceedingly'' low quality. The Alpha Centauri star system has 3 ''physical'' {{w|star}}s: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. The offscreen person has misconstrued this fact of the system as some kind of review.
-The title text furthers the pun. Some online star rating systems also allow partial stars, such as a half-star, to allow more precision in rating (e.g. rating 2.5 stars instead of being forced to chose 3 stars or 2 stars), or display an average collective rating as partial stars (e.g. showing 2.5 stars when five people have rated 3 stars and five people have rated 2 stars). Alpha Centauri's "half star" refers to Proxima Centauri, a {{w|red dwarf}}, which is a type of low-mass star. According to the offscreen person, this barely qualifies it to be a star. Furthermore, Proxima Centauri is nearly 13,000 AU (0.21 light years) away from the other 2 stars in the system, so it was long unknown whether Proxima Centauri was gravitationally bound to the Centauri star system.
+The title text furthers the pun. Some online star rating systems also allow partial stars, such as a half-star, to allow more precision in rating (e.g. rating 2.5 stars instead of being forced to chose 3 stars or 2 stars), or display an average collective rating as partial stars (e.g. showing 2.5 stars when five people have rated 3 stars and five people have rated 2 stars). Alpha Centauri's "half star" refers to Proxima Centauri, a {{w|red dwarf}}, which is a type of low-mass star. According to the offscreen person, this barely qualifies it to be a star. Furthermore, Proxima Centauri is nearly 13,000 AU (0.21 light years) away from the other 2 stars in the system, so it was long unknown whether Proxima Centauri was gravitationally bound to the Alpha Centauri star system.
 ===Calculations===

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 All numbers are rounded after subsequent calculations.
-According to [https://www.space.com/41447-parker-solar-probe-fastest-spacecraft-ever.html space.com] the fastest spacecraft ever will be the Parker Solar Probe which will reach 430,000 mph (692,000 km/h) as it reaches its closest point orbiting the sun. This is just over half of 1% of the needed speed of the Alpha Centauri vehicle proposed in the comic. The Voyager 1 spacecraft, launched in 1977, is currently traveling at about 38,000 mph (61,000 km/h).
+According to [https://www.space.com/41447-parker-solar-probe-fastest-spacecraft-ever.html space.com] the fastest spacecraft ever will be the {{w|Parker Solar Probe}} which will reach 430,000 mph (692,000 km/h) as it reaches its closest point orbiting the sun. This is just over half of 1% of the needed speed of the Alpha Centauri vehicle proposed in the comic. The {{w|Voyager 1| Voyager 1 spacecraft}}, launched in 1977, is currently traveling at about 38,000 mph (61,000 km/h).
 Distance to Alpha Centauri system = 4.367ly

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 Online rating systems, such as {{w|Yelp}}, often use {{w|Star (classification)|star rating system}}s, with more stars indicating higher quality, up to an arbitrary maximum, such as five stars to indicate the best rating. Due to the nature of 5 star rating systems, as shown in in comic [[1098: Star Ratings]], anything scoring less than 4 out of 5 in a 5 star rating system is crap; and in a 10-star rating system, scoring a mere 3 stars out of a possible 10 stars would be ''exceedingly'' low quality. The Alpha Centauri star system has 3 ''physical'' {{w|star}}s: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. The offscreen person has misconstrued this fact of the system as some kind of review.
-The title text furthers the pun. Some online star rating systems also allow partial stars, such as a half-star, to allow more precision in rating (e.g. rating 2.5 stars instead of being forced to chose 3 stars or 2 stars), or display an average collective rating as partial stars (e.g. showing 2.5 stars when five people have rated 3 stars and five people have rated 2 stars). Alpha Centauri's "half star" refers to Proxima Centauri, a {{w|red dwarf}}, which is a type of low-mass star. According to the offscreen person, this barely qualifies it to be a star. Furthermore, Proxima Centauri is nearly 13,000 AU (0.21 light years) away from the other 2 stars in the system, so it was long unknown whether Proxima Centauri was gravitationally bound to the Alpha Centauri star system.
+The title text furthers the pun. Some online star rating systems also allow partial stars, such as a half-star, to allow more precision in rating (e.g. rating 2.5 stars instead of being forced to chose 3 stars or 2 stars), or display an average collective rating as partial stars (e.g. showing 2.5 stars when five people have rated 3 stars and five people have rated 2 stars). Alpha Centauri's "half star" refers to Proxima Centauri, a {{w|red dwarf}}, which is a type of low-mass star. According to the offscreen person, this barely qualifies it to be a star. Furthermore, Proxima Centauri is nearly 13,000 AU (0.21 light years) away from the other 2 stars in the system, so it was long unknown whether Proxima Centauri was gravitationally bound to the Centauri star system.
 ===Calculations===

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 Further, the top speed is fast enough to require a recalculation using relativistic physics to model the problem.  This means that the energy budget will need to increase, as the relativistic mass of the probe will increase, requiring more force (and thus more energy) to accelerate and decelerate near its top speed than this calculation returns.
-[https://en.wikipedia.org/wiki/Breakthrough_Starshot Active], laser based propulsion methods require currently non-existent and purely specualtive laser and materials technologies, as well as a powerplant equivalent to 12,500 of the [https://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/ World's Largest Nuclear Plant] to transport sub-gram masses on this timescale.  This also assumes that any probes can be steered accurately enough across interstellar distances to come close enough to image with any resolution the bodies they will be passing at a non-trivial fraction of c.
+[https://en.wikipedia.org/wiki/Breakthrough_Starshot Active], laser based propulsion methods require currently non-existent and purely speculative laser and materials technologies, as well as a power plant equivalent to 12,500 of the [https://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/ World's Largest Nuclear Plant] to transport sub-gram masses on this timescale.  This also assumes that any probes can be steered accurately enough across interstellar distances to come close enough to image with any resolution the bodies they will be passing at a non-trivial fraction of c.
 Short of FTL travel or near-perfect mass-energy conversion technology, transporting more than a fraction of a gram of material to Alpha Centauri in a human lifetime will be unachievable.  Short of an enormous breakthrough in power generation, transporting even a fraction of a gram is impossible.