The Star That Can't Exist

Recent questions

• Can stars naturally appear green in color?

  Stars cannot naturally appear green due to the physics of starlight emission. Despite the potential to tune a star's temperature to emit light in the green band, the overall combination of red and blue light results in white light. This phenomenon is a result of the way stars emit light through thermal radiation, with their color determined by their temperature. Even altering the constants of the universe would not create a green star, as the physics behind starlight emission prevents it. The only way to observe a green star is through an optical illusion known as the green flash effect when viewing stars through Earth's atmosphere.

• How can a green star be artificially created?

  Creating a green star artificially would require enveloping a star in a green filter, a task that can only be achieved by a highly advanced civilization. The nature of stars and the physics behind their color make it impossible for a star to naturally emit green light. By manipulating the light emitted by a star through a green filter, it is theoretically possible to observe a green star. This concept raises questions about the potential for deliberate cosmic art or communication by extraterrestrial civilizations, as the appearance of a green star in the universe would be a technosignature of advanced beings.

• Are green stars a common occurrence in the universe?

  Green stars are not naturally occurring in our universe or a broader multiverse. The physics behind starlight emission and the way stars emit light through thermal radiation make it impossible for stars to naturally appear green in color. While stars can emit light at multiple colors simultaneously, the combination of red and blue light results in white light overall. The absence of green stars in the universe suggests that any observation of a green star would likely be artificial in nature, potentially created by advanced civilizations.

• How can the color of stars be determined?

  The color of a star is influenced by its temperature, with stars emitting light at multiple colors simultaneously. Stars emit light through thermal radiation, with their appearance determined by the outermost layer known as the photosphere. By analyzing the temperature of a star, astronomers can determine the color it emits. Despite the possibility of tuning a star's temperature to peak in the green band, the overall light emitted by stars results in white light due to the contributions of red and blue.

• Is it possible to verify the color of stars online?

  Yes, the colors of many stars can be checked online through services like SIMBAD. These databases provide information on various astronomical objects, including stars, allowing users to verify the colors of stars. Discovering a green star, even if not of alien origin, could unveil a new phenomenon in the universe. The absence of naturally occurring green stars in the universe suggests that any observation of a green star would be a significant discovery, challenging our understanding of the cosmos and potentially indicating the presence of advanced civilizations.