What is the Difference Between Dark Energy and Dark Matter?

🆚 Go to Comparative Table 🆚

Dark energy and dark matter are two distinct phenomena that make up a significant portion of the universe. They are both invisible and mysterious, but they have different effects on the universe and its expansion.

Dark Matter:

  • Makes up about 27% of the universe's total mass and energy.
  • Acts as an attractive force, pulling galaxies together.
  • Interacts with gravity but does not reflect, absorb, or emit light.
  • Effects are manifest on length scales of roughly 10 megaparsecs and smaller.
  • The nature of dark matter is still unknown, but it is believed to consist of non-baryonic particles.

Dark Energy:

  • Accounts for roughly 68% of the universe's total mass and energy.
  • Acts as a repulsive force, pushing galaxies apart.
  • Described as an anti-gravity force.
  • Relevant on large scales of roughly 1,000 megaparsecs or greater.
  • The exact nature of dark energy is still unknown, and its existence is mostly inferred from Albert Einstein's equations.

In summary, dark matter is an attractive force that affects objects on smaller scales, while dark energy is a repulsive force that influences the expansion of the universe on larger scales. Despite their similar names, dark matter and dark energy have opposite effects on the universe, and their natures remain elusive to scientists.

Comparative Table: Dark Energy vs Dark Matter

Here is a table summarizing the differences between dark energy and dark matter:

Feature Dark Energy Dark Matter
Definition A mysterious energy form that permeates all of space and is responsible for the accelerated expansion of the universe. A mysterious matter form that does not emit, reflect, or absorb light but interacts with other matter through gravity, providing additional gravitational force to hold galaxies together.
Effect on Universe Causes the expansion of the universe to accelerate. Slows down the expansion of the universe.
Composition Unknown, but accounts for approximately 68% of the universe's total mass and energy. Hypothesized to be made of massive particles that interact with other matter through gravity, but the exact composition remains unknown.
Detection Evidence comes from telescopic observations of distant supernova and the expansion of the universe. Evidence comes from the motion of galaxies and the rotation of galaxies, which suggests the presence of additional gravitational force.

Despite their names, dark energy and dark matter are not directly related. Dark energy is an energy form that fills space and causes the expansion of the universe to accelerate, while dark matter is a form of matter that interacts with other matter through gravity and affects the rotation of galaxies. They both make up a significant portion of the universe's mass-energy content, with dark energy accounting for about 68% and dark matter for about 27%. The exact nature of both dark energy and dark matter remains unknown, and scientists continue to study these phenomena to better understand their properties and origins.