Editing 2878: Supernova

{{comic
| number    = 2878
| date      = January 8, 2024
| title     = Supernova
| image     = supernova_2x.png
| imagesize = 348x227px
| noexpand  = true
| titletext = They're a little cagey about exactly where the crossover point lies relative to the likelihood of devastating effects on the planet.
}}

==Explanation==
A {{w|supernova}} occurs when a heavy star can no longer produce enough energy to fight its own gravity, e.g. because its fuel runs out ({{w|type II supernova|type II}}) or because it has accreted too much mass from a binary companion ({{w|type Ia supernova|type Ia}}). The collapsing mass leads to a violent explosion, one of the most interesting events for astronomers to observe and one that can be used to glean information about the universe. 

At first glance, the curved line on this graph is matches that of the typical {{w|light curve}} of a type Ia supernova, constructed by plotting the brightness of the supernova as a function of time, with negative values indicating a logarithmic luminosity scale (below zero means a linear luminosity of less than the unit amount). In the event of a supernova, a star (which may previously have been unremarkable) becomes notably bright over a short period of time before trailing off again to leave a stellar remnant and expanding cloud of ejecta. Around the time of this comic's release new constraints on the expansion of the universe from the observation of type Ia supernovae were [https://news.fnal.gov/2024/01/final-supernova-results-from-dark-energy-survey-offer-unique-insights-into-the-expansion-of-the-universe/ published], which used the regular shape of their light curves to establish a distance scale.

However, this comic reimagines the shape of a light curve graph to depict the relationship between the distance of supernovae from Earth, and the consequent happiness of astronomers, which happens to take a similar form. The further away the supernova occurs, the less detail can be learned from it, so the graph beyond the maximum happiness distance appears to show an {{wiktionary|asymptotic}} approach to less and less astronomer happiness. On the other hand, a {{w|near-earth supernova}} close enough to flood the Earth with significant amounts of gamma and X-ray radiation might be considered ''too'' close. Its radiation could destroy life on Earth, or at least significantly harm the biosphere, which would be a bad thing.{{cn}} Astronomers (and many others) would be really unhappy if that happened, shown as a sharp drop in happiness towards smaller distances and negative happiness values for a supernova that is very close. In fact, if a supernova were to instantly destroy Earth, or kill off all life on it, astronomers may no longer be able to be happy or unhappy (depending on your theological/spiritual feelings), so distance values close to zero have undefined astronomer happiness values.

Many astronomers watch and study the stars in the night sky, even those that don't change appreciably over human timescales, but observing and recording such a huge event would be interesting for many reasons. Humans can observe some supernovae with the naked eye, especially if they occur within {{w|Milky Way|our own galaxy}}. A potential supernova in the news lately is {{w|Betelgeuse}}, a {{w|red giant}} star that is the left shoulder in the constellation Orion. About 430 light years from the Sun, it has been pulsating, dimming and brightening over exceedingly short time scales compared to the tens of millions of years such a big star is expected to burn. Betelgeuse should be far enough away from Earth that the inevitable explosion would be safe enough for life on Earth (although [https://www.skyatnightmagazine.com/space-science/earth-danger-betelgeuse-supernova some assessments] are not so sure), but it ''will'' outshine all other stars in the night sky, competing with the Moon, and could even be visible during daytime. This would be a dream come true for many astronomers and something obvious to others interested in the night sky. In the first [[:Category:Stargazing | Stargazing]] comic, [[1644: Stargazing | 1644]], the wish that it goes supernova (in [[Randall|Randall's]] lifetime) is clearly expressed.

Since this ''should'' be safe for us, and since it would be a spectacle not seen at least since the start of recorded history, and unlikely to be seen again by human eyes, this would make astronomers very happy, not just from all they could learn, but also from all the increased interest in gazing at the sky with the 'new' star (and then seeing what happens to it next).
There are thought to be about three supernovae occurring per century within our own galaxy (most of which are much further away than Betelgeuse), and many other galaxies within which a supernova explosion can be detected. These remain useful to see, and are often studied as intensively as possible, but have decreasing amounts of thrill to them and are harder to notice/record in the early stages of the explosion (or immediately before, to add even more understanding).

The title text expands upon the point of "too close" supernovae, claiming that astronomers are not quite clear or perhaps unwilling to admit how close they would like a supernova to be. If it were {{what if|73|close enough}} to severely impact the quality of human life, they would presumably not be happy, but the title text suggests that they might actually be willing to accept some trouble on Earth if they get to see a supernova comparatively close by.

This is the second comic in a row that mentions exploding stars, after [[2877: Fever]], which like this comic is also a [[:Category:Charts|Charts comic]].

==Transcript==
:[A graph is shown where the axes are labeled and arrows are pointing upward above the Y axis label and to the right above the X axis label. There is a single line on the graph that peaks close to the Y axis, where it reaches close to the top of the drawn part of the Y axis. Then the line approaches the X axis asymptotically towards the far right. But closer to the Y axis, the peak line goes almost vertically down, and continues far below the "bottom of the chart", outside of the boundary of the graph that was only supposed to be above the X axis.]
:Y axis: How happy astronomers are
:X axis: How far away the new supernova is

{{comic discussion}}

[[Category:Line graphs]]
[[Category:Astronomy]]