1633: Possible Undiscovered Planets - Revision history

Chronotix: /* Table of items in the chart */

2025-10-01T11:41:59Z

‎Table of items in the chart

Chronotix: /* Table of items in the chart */

2025-10-01T11:40:49Z

‎Table of items in the chart

Chronotix: /* Explanation */

2025-10-01T11:36:47Z

‎Explanation

42.book.addict at 18:27, 17 October 2024

2024-10-17T18:27:06Z

42.book.addict at 18:26, 17 October 2024

2024-10-17T18:26:02Z

Peregrine: Typo: it's → its

2022-08-07T06:47:28Z

Typo: it's → its

Jacky720: rv

2022-05-04T21:10:46Z

Show changes

Ex Kay Cee Dee at 20:10, 4 May 2022

2022-05-04T20:10:29Z

Show changes

While False: Undo revision 240412 by Ex Kay Cee Dee (talk)

2022-05-04T17:48:41Z

Undo revision 240412 by Ex Kay Cee Dee (talk)

Show changes

Ex Kay Cee Dee at 17:17, 4 May 2022

2022-05-04T17:17:30Z

Show changes

@@ Line 110: / Line 110: @@
 | style="background-color:pink;"| Dwarf planets||{{sort|03900000|13 AU}}||{{sort|04300000|5.7 ly}}||{{sort|031000|170 km}}||{{sort|02700|16,000 km}}||Dwarf planets can in principle be anywhere in the solar system. But this region is shaded pink as it only covers undiscovered dwarf planets (similar to undiscovered planets) and thus they should be at least a given distance away, before it is realistic they would not already have been discovered. Also they need to be a certain size to be able to round themselves under their own gravity. And if they are too big, it is not realistic that they are only dwarf planets. The region reaches out to the next star as the edge of the graph is almost at 6 light-years (ly)
 |-
-| style="background-color:#FF748C;"| '''{{w|Planets beyond Neptune|Possible undiscovered planets}}'''||{{sort|042000000|100 AU}}||{{sort|04400000|5.7 ly}}||{{sort|032000|3,600 km}}||{{sort|039000|300,000 km}}||This is the region the whole comic is about. The label is not written in this light red shaded region in order to leave space for w the label for '''Planet Nine?'''. Instead the explanation is given with a label at a small rectangle at the top left with the same color. It is in this region there could still be undiscovered planets. They have to have a certain size to be a planet if they are this far away, and also have to be this far away before it is realistic they would not already have been discovered. If they were any bigger, it would be like with the other planet regions to the left, that they would turn into a brown dwarf, (or at least Saturn sized planet) and although maybe not visible with telescopes just above this size, they would have been spotted by the WISE survey (see below). The region reaches out to the next star as the edge of the graph is almost at 6 light-years (ly)
+| style="background-color:#FF748C;"| '''{{w|Planets beyond Neptune|Possible undiscovered planets}}'''||{{sort|042000000|100 AU}}||{{sort|04400000|5.7 ly}}||{{sort|032000|3,600 km}}||{{sort|039000|300,000 km}}||This is the region the whole comic is about. The label is not written in this light red shaded region in order to leave space for the label for '''Planet Nine?'''. Instead the explanation is given with a label at a small rectangle at the top left with the same color. It is in this region there could still be undiscovered planets. They have to have a certain size to be a planet if they are this far away, and also have to be this far away before it is realistic they would not already have been discovered. If they were any bigger, it would be like with the other planet regions to the left, that they would turn into a brown dwarf, (or at least Saturn sized planet) and although maybe not visible with telescopes just above this size, they would have been spotted by the WISE survey (see below). The region reaches out to the next star as the edge of the graph is almost at 6 light-years (ly)
 |-
 |Planets ruled out by the {{w|Wide-field Infrared Survey Explorer|WISE survey}}||{{sort|043000000|450 AU}}||{{sort|04500000|5.7 ly}}||{{sort|043000|70,000 km}}||{{sort|0430000|10<sup>6</sup> km}}||This region refers to the Wide-field Infrared Survey Explorer (WISE), a {{w|space telescope}} designed to look for warm objects such as {{w|brown dwarf}}s, which generate heat at their centers. It was capable of detecting Saturn-sized or larger planets in the outer reaches of our solar system, but did not find any. WISE would not have detected "Planet Nine" (even if it exists) because it is too small and thus too cold to be detected. If the objects got any bigger than the upper limit they would turn into small stars, which would be visible during the night probably even with the naked eye. This region is the last section below the ''could see them during the day'' region. The WISE region reaches out to the next star as the edge of the graph is almost at 6 light-years (ly)

@@ Line 110: / Line 110: @@
 | style="background-color:pink;"| Dwarf planets||{{sort|03900000|13 AU}}||{{sort|04300000|5.7 ly}}||{{sort|031000|170 km}}||{{sort|02700|16,000 km}}||Dwarf planets can in principle be anywhere in the solar system. But this region is shaded pink as it only covers undiscovered dwarf planets (similar to undiscovered planets) and thus they should be at least a given distance away, before it is realistic they would not already have been discovered. Also they need to be a certain size to be able to round themselves under their own gravity. And if they are too big, it is not realistic that they are only dwarf planets. The region reaches out to the next star as the edge of the graph is almost at 6 light-years (ly)
 |-
-| style="background-color:#FF748C;"| '''{{w|Planets beyond Neptune|Possible undiscovered planets}}'''||{{sort|042000000|100 AU}}||{{sort|04400000|5.7 ly}}||{{sort|032000|3,600 km}}||{{sort|039000|300,000 km}}||This is the region the whole comic is about. The label is not written in this light red shaded region, as there should be space to write a label for '''Planet Nine?'''. Instead the explanation is given with a label at a small rectangle at the top left with the same color. It is in this region there could still be undiscovered planets. They have to have a certain size to be a planet if they are this far away, and also have to be this far away before it is realistic they would not already have been discovered. If they were any bigger, it would be like with the other planet regions to the left, that they would turn into a brown dwarf, (or at least Saturn sized planet) and although maybe not visible with telescopes just above this size, they would have been spotted by the WISE survey (see below). The region reaches out to the next star as the edge of the graph is almost at 6 light-years (ly)
+| style="background-color:#FF748C;"| '''{{w|Planets beyond Neptune|Possible undiscovered planets}}'''||{{sort|042000000|100 AU}}||{{sort|04400000|5.7 ly}}||{{sort|032000|3,600 km}}||{{sort|039000|300,000 km}}||This is the region the whole comic is about. The label is not written in this light red shaded region in order to leave space for w the label for '''Planet Nine?'''. Instead the explanation is given with a label at a small rectangle at the top left with the same color. It is in this region there could still be undiscovered planets. They have to have a certain size to be a planet if they are this far away, and also have to be this far away before it is realistic they would not already have been discovered. If they were any bigger, it would be like with the other planet regions to the left, that they would turn into a brown dwarf, (or at least Saturn sized planet) and although maybe not visible with telescopes just above this size, they would have been spotted by the WISE survey (see below). The region reaches out to the next star as the edge of the graph is almost at 6 light-years (ly)
 |-
 |Planets ruled out by the {{w|Wide-field Infrared Survey Explorer|WISE survey}}||{{sort|043000000|450 AU}}||{{sort|04500000|5.7 ly}}||{{sort|043000|70,000 km}}||{{sort|0430000|10<sup>6</sup> km}}||This region refers to the Wide-field Infrared Survey Explorer (WISE), a {{w|space telescope}} designed to look for warm objects such as {{w|brown dwarf}}s, which generate heat at their centers. It was capable of detecting Saturn-sized or larger planets in the outer reaches of our solar system, but did not find any. WISE would not have detected "Planet Nine" (even if it exists) because it is too small and thus too cold to be detected. If the objects got any bigger than the upper limit they would turn into small stars, which would be visible during the night probably even with the naked eye. This region is the last section below the ''could see them during the day'' region. The WISE region reaches out to the next star as the edge of the graph is almost at 6 light-years (ly)

@@ Line 29: / Line 29: @@
 The already known planets are prominently marked on the chart. They are the solid black dots. Besides Earth and ''Planet Nine?'', the bottom row of three small dots are {{w|Mercury (planet)|Mercury}}, {{w|Venus}} and {{w|Mars}}. The top row of four larger dots (but smaller than the dot that marks Earth) are (from left to right) {{w|Jupiter}} and {{w|Saturn}} (visible to the naked eye) and {{w|Uranus}} and Neptune (visible through a telescope).
-It is unclear how Randall is calculating these distances, especially to the three {{w|terrestrial planets}}, since neither of these options work: closest approach, average, mean, current or maximum distance. In the comic [[482: Height]] Randall shows (among other) the distance from the Earths surface to all the planets. For especially Venus and Mars he shows that their distance changes a lot based on theirs and Earth's orbital positions. But he has neither used these loops to base the dot size or position, as these loops clearly go closer than 1 AU and only one of the planets are drawn closer than that. It is thus unclear which of the three represents which planet, but in the '''[[#Table of items in the chart|table below]]''' it has been reasoned that the dot situated at the largest diameter of the three inner planets planets should represent Venus (12,000&nbsp;km) as it is almost twice as big as Mars (6,700&nbsp;km), which on the other hand is more similar to Mercury (5,000&nbsp;km) and given that the two dots furthest out are almost the same size, it would make most sense if they represent Mercury and Mars. Since the outer dot never comes closer than 2.5 AU and Mercury never gets further away than 1.5 AU it makes most sense to place Mercury as the middle of the three and Mars as the outer of the three dots.
+It is unclear how Randall is calculating these distances, especially to the three {{w|terrestrial planets}}, since none of these options work: closest approach, average, mean, current or maximum distance. In the comic [[482: Height]] Randall shows (among other) the distance from the Earth's surface to all the planets. For especially Venus and Mars he shows that their distance changes a lot based on theirs and Earth's orbital positions. But he has used these loops to base neither the dot size nor position, as these loops clearly go closer than 1 AU and only one of the planets are drawn closer than that. It is thus unclear which of the three represents which planet, but in the '''[[#Table of items in the chart|table below]]''' it has been reasoned that the dot situated at the largest diameter of the three inner planets planets should represent Venus (12,000&nbsp;km) as it is almost twice as big as Mars (6,700&nbsp;km), which on the other hand is more similar to Mercury (5,000&nbsp;km) and given that the two dots furthest out are almost the same size, it would make most sense if they represent Mercury and Mars. Since the outer dot never comes closer than 2.5 AU and Mercury never gets further away than 1.5 AU it makes most sense to place Mercury as the middle of the three and Mars as the outer of the three dots.
 Below some objects are mentioned that are not on the chart, and also other errors in position (probably due the hasty creation of such a complex comic.) Many of these objects as well as the planets with the errors mentioned clearly revealed can be see in this '''[http://www.explainxkcd.com/wiki/images/e/ef/Modified_possible_undiscovered_planets.png modified image]''', which is also inserted and explained [[#Image used to create data for the table|in the trivia section]] below.

@@ Line 220: / Line 220: @@
 *An updated version with many more details have been added since the first version.
 **See more details [[#Info on new version|below]] the image.
-[[File:Modified_possible_undiscovered_planets.png|750]]
+[[File:Modified_possible_undiscovered_planets.png|750px]]
 ====Info on new version====
 *New features in the image include more precisely marked dots of the planets and other objects.

@@ Line 220: / Line 220: @@
 *An updated version with many more details have been added since the first version.
 **See more details [[#Info on new version|below]] the image.
-[[File:Modified_possible_undiscovered_planets.png]]
+[[File:Modified_possible_undiscovered_planets.png|750]]
 ====Info on new version====
 *New features in the image include more precisely marked dots of the planets and other objects.

@@ Line 23: / Line 23: @@
 The distance calculations are somewhat problematic (see more on this below). Close distances seem to be measured from the surface of Randall's body (skin/eyes) rather than from his center of mass. All the planets (and moon) that are marked on the chart are so far away that it will not matter if the distance is measured from Randall's surface, his center of mass, or by the way anywhere on {{w|Earth}}. Also, the planets' diameters are so much smaller than the distance from Earth that their real size would hardly take up any space in the chart due to the {{w|Logarithmic scale|log-scale}}. The dots marking these 7 planets are thus not drawn to scale that should represent their actual size compared with the other planets. But their distance from Earth (and Randall) is not constant even on the log-scale, especially not for the nearest planets, as they can be on either side of the {{w|Sun}} compared to Earth.
-The chart correctly states that if there was a planet that was at a distance from him smaller than its diameter, he would be inside it (although at the bottom of that region, it's more like the planet that would be inside him, as this line goes down to a diameter of 1&nbsp;cm). If the distance is to the planets center, this would also fit if he was only a radius away from the planet. As Randall is not inside the Earth but really close to it, Earth is correctly positioned on this line. However, for Earth, which is marked with the largest of the dots, he seems to have put himself a full Earth diameter away from Earth. Even using the center of mass of Earth as it's position he should only have been 6,350&nbsp;km away from it, but now he places the measuring point of his distance to Earth on the opposite side of the Earth so his distance to it is equal to its diameter (which would make a choosing a distance of 0&nbsp;km just as correct). Earth is just left of the 10,000&nbsp;km line on both axis, and Earth has a diameter of 12,700&nbsp;km, which will fit fine with the center of the dot, but not with the distance which should have been the maximum distance Randall could be from it (0 or 6350&nbsp;km depending on the definition of distance from Randall).
+The chart correctly states that if there was a planet that was at a distance from him smaller than its diameter, he would be inside it (although at the bottom of that region, it's more like the planet that would be inside him, as this line goes down to a diameter of 1&nbsp;cm). If the distance is to the planets center, this would also fit if he was only a radius away from the planet. As Randall is not inside the Earth but really close to it, Earth is correctly positioned on this line. However, for Earth, which is marked with the largest of the dots, he seems to have put himself a full Earth diameter away from Earth. Even using the center of mass of Earth as its position he should only have been 6,350&nbsp;km away from it, but now he places the measuring point of his distance to Earth on the opposite side of the Earth so his distance to it is equal to its diameter (which would make a choosing a distance of 0&nbsp;km just as correct). Earth is just left of the 10,000&nbsp;km line on both axis, and Earth has a diameter of 12,700&nbsp;km, which will fit fine with the center of the dot, but not with the distance which should have been the maximum distance Randall could be from it (0 or 6350&nbsp;km depending on the definition of distance from Randall).
 The {{w|IAU definition of planet}} requires a solar orbit, gravitational rounding, and "clearing the neighborhood", a controversial (at the time of its introduction) calculation of relative size that excludes {{w|Kuiper Belt Objects}} such as Pluto. The calculation regarding Planet Nine would make it large enough to meet the IAU definition. Using this definition the chart quickly rules out birds and bugs, although at a glance they could be mistaken for planets, something that is especially the case for planes (at night) which are even called ''fool’s planets’'' in the chart, a reference to {{w|fool's Gold}}. Note that anything that is actually on Earth is positioned within 60&nbsp;km from Randall. This is because if it is further away he cannot see them due to the curvature of the Earth. This does not mean that he intends to indicate that they cannot be further away from him than that.