Dark matter and dark energy makes up 95% of the total mass-energy density in the universe. However, we know almost nothing about them; neither can we observe any dark matter or dark energy directly. So what if aliens are made of dark matter or dark energy? Can this be the reason we have not been able to find any aliens?
We are not even sure dark matter or dark energy exist or not but without them lots of things will not make sense.
- Primary evidence for dark matter comes from calculations showing many galaxies would fly apart instead of rotating, or would not have formed or move as they do, if they did not contain a large amount of unseen matter. Other lines of evidence include observations in gravitational lensing, from the cosmic microwave background, also astronomical observations of the observable universe’s current structure, the formation and evolution of galaxies, mass location during galactic collisions, and the motion of galaxies within galaxy clusters.
- The evidence for dark energy is indirect but comes from three independent sources: Distance measurements and their relation to redshift, which suggest the universe has expanded more in the last half of its life; The theoretical need for a type of additional energy that is not matter or dark matter to form the observationally flat universe (absence of any detectable global curvature); Measures of large-scale wave-patterns of mass density in the universe.
In the centre of this image, taken with the NASA/ESA Hubble Space Telescope, is the galaxy cluster SDSS J1038+4849 — and it seems to be smiling. You can make out its two orange eyes and white button nose. In the case of this “happy face”, the two eyes are very bright galaxies and the misleading smile lines are actually arcs caused by an effect known as strong gravitational lensing. Galaxy clusters are the most massive structures in the Universe and exert such a powerful gravitational pull that they warp the spacetime around them and act as cosmic lenses which can magnify, distort and bend the light behind them. This phenomenon, crucial to many of Hubble’s discoveries, can be explained by Einstein’s theory of general relativity. In this special case of gravitational lensing, a ring — known as an Einstein Ring — is produced from this bending of light, a consequence of the exact and symmetrical alignment of the source, lens and observer and resulting in the ring-like structure we see here. Hubble has provided astronomers with the tools to probe these massive galaxies and model their lensing effects, allowing us to peer further into the early Universe than ever before. This object was studied by Hubble’s Wide Field and Planetary Camera 2 (WFPC2) and Wide Field Camera 3 (WFC3) as part of a survey of strong lenses.
Dark matter doesn’t interact with itself the same way regular matter does, but from a paper from Manoj Kaplinghat et. al. (Dark Matter Halos as Particle Colliders: A Unified Solution to Small-Scale Structure Puzzles from Dwarfs to Clusters) suggests that given simple gravitation, dark matter haloes should have denser cores than what astronomers observe. Perhaps there is some sort of heating that puffs up the haloes. If it is true then there should be some sort of “Dark light” coming from dark matter, since dark matter doesn’t radiate any photons at all. Isn’t it exciting enough to think that dark matter can interact with itself? As interacting can cause force and eventually form “objects” and even life.
Please leave a comment if you have any questions. 😄