Alderson disk

A schematic illustration of an Alderson disk

An Alderson disk[1][2] (named after Dan Alderson, its originator) is a hypothetical artificial astronomical megastructure, like Larry Niven's Ringworld and the Dyson sphere. The disk is a giant platter with a thickness of several thousand miles. The Sun rests in the hole at the center of the disk. The outer perimeter of an Alderson disk would be roughly equivalent to the orbit of Mars or Jupiter. According to the proposal, a sufficiently large disk would have a larger mass than its Sun.

The hole would be surrounded by a thousand-mile-high wall to prevent the atmosphere from drifting into the Sun.[3] The outer rim would not require a wall.

The mechanical stresses within the disc would be far beyond what any known material can stand, thus relegating such a structure to the realm of exploratory engineering until materials and construction science become sufficiently advanced.[4] Building a megastructure of this magnitude would require an amount of material that far surpasses the amount of material found in the Solar System.

Life could exist on either side of the disk, though life in close proximity to the sun would be impossible without sufficient heat protection. Conversely, beings residing far away from the Sun would freeze without the requisite heating equipment. Therefore, for the entirety of such a structure to be made habitable, it would have to include a vast number of life support systems. Even without such systems, the habitable surface area would be an equivalent of tens to hundreds of millions of Earths.

Because the Sun remains stationary, there is no day/night cycle, only a perpetual twilight. This could be solved by forcing the Sun to bob up and down within the disk, lighting first one side then the other.[5]

  1. ^ Hadhazy, Adam (5 August 2014). "Could We Build a Disk Bigger Than a Star?". Popular Mechanics. Retrieved 23 December 2016.
  2. ^ Wegert, David (2014). Spirit Guides from the Future. Author House. ISBN 978-1491850145 – via Google Books.
  3. ^ Adam Hadhazy (August 4, 2014). "Could We Build a Disk Bigger Than a Star?". Popular Mechanics. Retrieved April 2, 2023.
  4. ^ Matthew S. Williams (March 10, 2019). "Megastructures – A Sign of Larger than Life Aliens?". interestingengineering.com. Retrieved April 2, 2023.
  5. ^ Niven, Larry (1974). "Bigger Than Worlds". A Hole in Space. New York: Ballantine Books. pp. 123–124. ISBN 0345240111. This essay was first published in Analog magazine (1974), and is also anthologised in Playgrounds of the Mind.