Context:
Recently, Astronomers spotted unusual object falling in the black hole ‘mass gap’.
Newly Discovered Object:
- Object resides in a binary system within the star cluster NGC 1851
- Its companion is a millisecond pulsar – a rapidly spinning neutron star that emits regular pulses of radio waves.
- By studying the pulsar’s orbital motion, astronomers estimated the mass of the unknown object to be between 2.09 and 2.71 solar masses. This places it within the mass gap.
Mass Gap: Gap between the mass of the Neutron star and the Black hole
Black Hole:
- Cosmic object with strong gravity that nothing can escape from it, not even light.
- Boundary of no escape is called the event horizon.
- Intensity of a black hole – “20 times the sun’s mass could fit easily in a 16 km ball”.
- Since no light can escape, none can bounce back. This makes the black hole invisible to our eyes and telescopes that we rely on.
- They are so dense and their gravitational pulls so strong, that their cores are permanently shrouded from the universe
- Mass of small black holes – around 5 to 20 times the mass of the sun (solar mass);
- Types of black hole:
- Stellar Black Hole: Formed by the collapse of a single massive star.
- Intermediate Black Hole: Masses between 100 and 1,00,000 times that of the sun.
- Supermassive Black Hole: Masses ranging from millions to billions of times that of the sun, found at the centres of most galaxies.
Neutron Stars:
- Created after a star dies violently after a supernova explosion.
- Densest known stellar objects in the universe, second only to the black holes.
- Extremely strong magnetic fields, much stronger than those of regular stars.
- These magnetic fields can give rise to intense radiation emissions, including beams of electromagnetic radiation and particle streams, which are observable as pulsars
- Maximum mass is thought to be around 2.2 solar masses.
Black Hole vs. Neutron Stars:
| Black Hole | Neutron Star |
| Larger mass or size | Smaller mass or size |
| Less brighter | More brighter |
| Created after a star dies violently after a supernova explosion | Created after a star dies violently after a supernova explosion |
| Not solid objects | Densest solid matter in space |
| Trap all the surrounding light that crosses its vicinity | Do not trap all the surrounding light that crosses its vicinity |
Read more about: Black Hole
Source: The Hindu
Previous Year Question
What is the purpose of ‘evolved Laser Interferometer Space Antenna (eLISA) project?
[UPSC Civil Services Exam – 2017 Prelims]
(a) To detect neutrinos
(b) To detect gravitational waves
(c) To detect the effectiveness of missile defence system
(d) To study the effect of solar flares on our communication systems
Answer: (b)
