Talk:Outer space

The article currently defines interplanetary space as "the space dominated by the gravitation of the Sun", but interstellar space as " the physical space outside of the bubbles of plasma known as astrospheres, formed by stellar winds originating from individual stars, or formed by solar wind emanating from the Sun." The gravitational influence of the Sun extends hundreds of times farther out than the heliosphere. So which is it? The region of the heliosphere, or the region of the Sun's gravitational influence? Serendi^podous 11:51, 2 May 2025 (UTC)

Good point. The first can be corrected by removing "the space", so it then matches the reference. I went ahead and made the change. Thanks. Praemonitus (talk) 13:44, 2 May 2025 (UTC)

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In the section "Human access", subsection "Effect on biology and human bodies", the second sentence reads, "Species of lichen carried on the ESA BIOPAN facility survived exposure for ten days in 2007.". I simply request that the term "lichen" be hyperlinked to its respective Wikipedia page available at https://en.wikipedia.org/wiki/Lichen

I know that this is a VERY minor change, but I, at least, would appreciate the addition/modification. Thanks for the consideration! Dylanbeetcher (talk) 00:31, 17 June 2025 (UTC)

 Done M.Bitton (talk) 00:51, 17 June 2025 (UTC)

Theodore von Kármán did not argue "for an altitude where a vehicle would have to travel faster than orbital velocity to derive sufficient aerodynamic lift from the atmosphere to support itself, which he calculated to be at an altitude of about 83.8 km (52.1 mi)." There is no evidence for this. The references do not any technical work by von Kármán. Research of von Kármán's publications show that he theorized that at an altitude of 275,000, an aircraft would need to fly so fast that frictional heating would cause structural failure of materials then known (1956); his assumptions were superseded by subsequent technological developments. See https://www.academia.edu/165009488/The_Non_K%C3%A1rm%C3%A1n_Line_An_Urban_Legend_of_the_Space_Age Tgangale13 (talk) 20:53, 9 March 2026 (UTC)

One of the sources, https://www.astronomy.com/space-exploration/the-karman-line-where-does-space-begin/, quotes his autobiography concerning the Karman line. I have adjusted the content accordingly. Johnjbarton (talk) 21:48, 9 March 2026 (UTC)

That source is non-authoritative. And how much of an "autobiography" could it possibly be, having been published four years after von Kármán's death, and how much of its material was cobbled together with von Kármán no longer around to review its accuracy? Von Kármán's 1956 paper is the authoritative source. Regarding the 275,000-ft flight regime, he stated:

"The upper limit for the velocity is computed in this diagram somewhat arbitrarily. The main engineering problem consists of finding methods that allow an extension of the temperature barrier toward higher velocities. The heat emission in continuous flight by radiation varies at a rapid rate as the surface temperature increases and also varies with the altitude. Unfortunately, at surface temperatures permissible for current materials, the radiation represents a small amount in comparison with the heat input to be expected. Therefore, artificial means are necessary to reduce the heat input or to transfer heat from the airplane or missile to the surrounding space."

Nothing about a "jurisdictional line." This was Andrew Haley's later invention based on his misunderstanding of von Kármán's technical paper. Tgangale13 (talk) 22:14, 9 March 2026 (UTC)

The quote you provide does not verify anything about "Karman line" which is the subject of the paragraph. According to

• McDowell, J. C. (2018). The edge of space: Revisiting the Karman Line. Acta Astronautica, 151, 668-677. The ‘von Karman line’ appears to be what mathematicians refer to as a ‘folk theorem’, arising out of a conference discussion but never formally published by him.

You dispute that he ever commented on the line so fine, we can remove that sentence. Johnjbarton (talk) 22:40, 9 March 2026 (UTC)

Yeah, Jonathan McDowell and I worked together on this subject in 2018. The "folk theorem" term is his, but it summed up the conclusion of my literature search. Not every authoritative source is to be found online. I have a scan of von Kármán's 1956 paper in my possession, which I'm happy to share with you. Again, I refer you to https://www.academia.edu/165009488/The_Non_K%C3%A1rm%C3%A1n_Line_An_Urban_Legend_of_the_Space_Age. I show von Kármán's 1956 diagram, which contains no line at the 275,000-ft altitude, or at any other altitude for that matter. As difficult as it is to prove an negative, it is the absence of any reference to a line in von Kármán's paper that makes the case, together with the fact that Haley published a paper in 1958 in which he took the same diagram and penciled in a "Kármán primary jurisdictional line" with references to a "Kepler regime," which I never once heard of in all my years as a working aerospace engineer. Haley, a lawyer, clearly did not understand von Kármán's work and misapplied it. Tgangale13 (talk) 23:15, 9 March 2026 (UTC)

This page's current definition of interplanetary space implies that it comprises the entire gravitational extent of the Sun. This is not correct. NASA has defined interstellar space as the region beyond the heliopause, which is a thousandth the radius of the region of the Sun's gravitational dominance. Serendi^podous 08:57, 12 March 2026 (UTC)

The definition comes from the cited source: "The boundary between interplanetary space and interstellar space is known as the heliopause and is believed to be approximately 110 to 160 astronomical units (AU) from the Sun." The insertion, "influence of the galactic environment starts to dominate over the Sun", isn't cited and can probably be extracted. Praemonitus (talk) 13:58, 12 March 2026 (UTC)

The section would likely be improved by reversing the order of the first two paragraphs. (Solar gravity is important for interplanetary trajectories, but putting any discussion of gravitation in the first paragraph of the section misleads readers into assuming gravity might define the outer boundary of interstellar space. I surmise the current reference to gravity is trying to establish inner boundaries around the planets, largely because the ordering of the sections appears to be from near to far. (— 𝐬𝐝𝐒𝐝𝐬 — - talk) 03:52, 13 March 2026 (UTC)

I made some changes, please review. Johnjbarton (talk) 15:37, 13 March 2026 (UTC)

Excellent rewrite. :) Serendi^podous 17:32, 13 March 2026 (UTC)