Missing Matter in the Universe: Discoveries and Implications

What is 'Missing' Matter in the Universe?

'Missing' matter refers to ordinary matter composed of protons and neutrons, also known as baryons, which was predicted to exist but not directly observed. Earlier surveys revealed that about half of this matter was unaccounted for, prompting further investigation into its nature and location.

How is Missing Matter Different from Dark Matter?

• Missing Matter: This includes ordinary matter such as atoms, gas, and dust that affects light, making it difficult to observe.
• Dark Matter: Unlike ordinary matter, dark matter does not emit, absorb, or reflect light. It remains invisible and is only detected through its gravitational effects.
• Function: Ordinary matter forms visible structures like stars and planets, whereas dark matter acts as the invisible framework that holds galaxies together.

Where Was the Missing Matter Found?

The missing matter was discovered within a thin, invisible gas known as the intergalactic medium, which exists between galaxies and resembles a cosmic web. Some of this matter was also detected in gaseous halos surrounding galaxies.

How Did Scientists Find This Matter?

Researchers utilized Fast Radio Bursts (FRBs)—short and intense bursts of radio waves originating from distant galaxies. As these waves traveled through space, they were slightly delayed and scattered by the surrounding matter. By measuring these changes, scientists were able to detect the elusive gas.

Why Were FRBs Important for This Discovery?

FRBs function similarly to cosmic X-rays. Just as X-rays reveal bones in the human body, FRBs expose hidden gas in the universe. They assist in mapping the density and structure of otherwise invisible matter, enhancing our understanding of cosmic composition.

How Much Ordinary Matter Exists in the Universe?

Ordinary matter constitutes approximately 16% of the total matter in the universe, with the remaining portion made up of dark matter and dark energy. Recent discoveries help account for the previously missing half of that 16%.

Why Could This Matter Not Be Seen Before?

This matter is extremely diffuse and does not emit strong light, making it challenging to detect. It resides in regions between galaxies that are predominantly empty, complicating observations using traditional telescopes.

What is the Intergalactic Medium?

The intergalactic medium consists of a diffuse, thin gas found in the vast expanse between galaxies. While it does not glow like stars or planets, it can be identified through its interactions with radiation, such as radio waves.

Why Does This Discovery Matter?

• This finding completes the mapping of the universe's matter.
• It validates scientific predictions derived from the Big Bang model.
• It opens new avenues for studying galaxy formation and evolution.

What Can India Learn or Do?

• Enhance radio astronomy infrastructure, such as the GMRT in Pune, to bolster cosmic research.
• Encourage collaborative efforts in FRB studies through international projects like the Square Kilometre Array.
• Promote public science education on space-related topics to inspire future generations.
• Support training in data science and AI for analyzing extensive cosmic datasets.

Frequently Asked Questions (FAQs)

Q1. What is missing matter in the universe?
Answer: Missing matter refers to ordinary matter, such as atoms and gas, that was predicted but not directly observed. It accounts for about half of the ordinary matter in the universe.

Q2. How is missing matter detected?
Answer: Scientists detect missing matter using Fast Radio Bursts (FRBs), which are bursts of radio waves that reveal hidden gas through their interactions with surrounding matter.

Q3. What role does the intergalactic medium play?
Answer: The intergalactic medium is a thin, diffuse gas between galaxies that contains missing ordinary matter. It can be detected through its interactions with cosmic radiation.

Q4. Why is dark matter important?
Answer: Dark matter, which does not emit light, is crucial for understanding the universe's structure. It forms the invisible framework that holds galaxies together.

Q5. How can India contribute to cosmic research?
Answer: India can enhance its radio astronomy infrastructure, foster international collaborations, and promote education in space science to contribute to cosmic research efforts.

UPSC Practice MCQs

Question 1: What is missing matter primarily made of?
A) Dark energy
B) Baryons
C) Neutrinos
D) Dark matter
Correct Answer: B

Question 2: Which tool is used to detect missing matter?
A) Optical telescopes
B) Fast Radio Bursts (FRBs)
C) Microwaves
D) Infrared sensors
Correct Answer: B

Question 3: What percentage of the universe is made up of ordinary matter?
A) 50%
B) 16%
C) 25%
D) 35%
Correct Answer: B

Question 4: Where is the intergalactic medium located?
A) Within galaxies
B) In cosmic voids
C) Between galaxies
D) Inside stars
Correct Answer: C