Dark matter is matter that does not emit or absorb light or radiation and can only be detected through its gravitational effects. It makes up 23% of the universe's energy. Its exact particle nature remains unknown. Dark matter was first hypothesized to account for discrepancies between the mass of large astronomical objects determined by their gravitational influence versus the mass calculated from the visible matter they contain. Understanding dark matter is important because it and dark energy make up over 90% of the universe's total energy.

1. DARK MATTER
SUBMITTTED BY:
2011-MM-69
Waqas Inam
SUBMITTED TO:
Sir Rauf Akhtar

2. What is Dark Matter?
The matter which neither emits nor
absorbs light or other radiations and the
only way to identify it is its gravitational
effects on galaxies, stars etc. Therefore,
Dark matter can not be seen with
telescope. Its constituent subatomic
particle is unknown yet.

4. Why is it important to know about it?

5. Our Universe’s energy comprises of;
• 73% Dark energy
• 23% Dark matter
• 4% Regular matter, like stars,
planets, and everything else.

6. Supposition Before Planck:
• Dark matter 22.7%
• Dark energy 72.8%
• Ordinary matter 4.5%

7. After Planck Observation:
• Dark matter 26.8%
• Dark energy 68.3%
• Ordinary matter 4.9%

10. The Proof of Existence of Dark Matter
Dark matter came to the attention of
astrophysicists due to difference between
the mass of large astronomical objects
determined from their gravitational effects,
and the mass calculated from the
"luminous matter" they contain: stars, gas
and dust.

11. That’s all
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