Topic 1: Pradhan Mantri Suryodaya Yojana

Why it is in news?

Prime Minister Narendra Modi on Monday (January 22) announced the ‘Pradhan Mantri Suryodaya Yojana’, a government scheme under which one crore households will get rooftop solar power systems.

What is the Pradhan Mantri Suryodaya Yojana?

• It is a government scheme under which one crore households will get rooftop solar power systems.
• The scheme targets the aim of achieving 40 GW of electricity generation through installation of Solar Grids on rooftops.
• The scheme will help reduce electricity bills of the “poor and middle class”, but also help in achieving India’s goal of becoming self-reliant in the energy sector.

Why it has been launched?

• In 2014, the government launched the Rooftop Solar Programme that aimed to achieve a cumulative installed capacity of 40 GigaWatts (GW) by 2022.
• However, this target couldn’t be achieved. As a result, the government extended the deadline from 2022 to 2026. The Pradhan Mantri Suryodaya Yojana seems to be a new attempt to help reach the target of 40 GW rooftop solar capacity.
• The scheme aims to expand India’s rooftop solar installed capacity in the residential sector by providing Central Financial Assistance and incentives to DISCOMs (distribution companies).

What is the present renewable energy installed capacity?

As per Ministry of Renewable Energy as on Dec 2023, Renewable Energy sources including large hydropower, have a combined installed capacity of 180.79 GW.

The following is the installed capacity for Renewable Energy:

What is the need for expansion of Solar Energy in India?

• As per the latest World Energy Outlook given by the International Energy Agency (IEA), India is expected to witness the largest energy demand growth for any country or region in the world over the next 30 years.
• In order to meet this humongous demand, the country would need a reliable source of energy, making it self-sufficient in its energy needs.
• Even though India has double has doubled down on its coal production in recent years, it also aims to reach 500 GW of renewable energy capacity by 2030.
• India has set a target to reduce the carbon intensity of the nation’s economy by less than 45% by the end of the decade, achieve 50 percent cumulative electric power installed by 2030 from renewables, and achieve net-zero carbon emissions by 2070. India aims for 500 GW of renewable energy installed capacity by 2030.

Topic 2: Solar System

In NEWS: Does the Solar system have a ninth planet after all? (Article of the Hindu)

Why Pluto was demoted from being Planet to that of being a dwarf planet?

The conditions for what classifies a “planet” as opposed to a “dwarf planet” were set by the International Astronomical Union, which were not met by Pluto. This led to Pluto being ousted from the status of Planet.

What are the conditions to be met by an astronomical body to be declared a Planet?

There are three criteria to be met by a fully-fledged planet as declared by International Astronomical Union. They are as below:

• It must orbit a star (example: as in our Solar System this would be the Sun).
• It must be big enough that gravity has forced it into a spherical shape.
• It must be big enough that its own gravity has cleared away any other objects of a similar size near its orbit.

It was the third criterion which was not met by Pluto. It was unable to clear its neighbouring region of other objects.

Is there a Planet Nine out there in our solar system?

As per California Institute of Technology in 2016, astronomers over there after modelling the dwarf planets and their observed paths concluded that mathematically there ought to be a ninth planet out there in our solar system.

Their modelling determined this planet would have to be about ten times the mass of Earth, and located some 90 billion kilometres away from the Sun (about 15 times farther then Pluto).

What are the challenges in finding the 9^th Planet as be theory?

One might assume it’s easy to determine whether such a planet exists. Just point a telescope towards where you think it is and look, right? If we can see galaxies billions of light years away, shouldn’t we be able to spot a ninth planet in our own Solar System?

• Well, the issue lies in how (not) bright this theoretical planet would be. Best estimates suggest it sits at the depth limit of Earth’s largest telescopes. In other words, it could be 600 times fainter than Pluto.
• The other challenge is where to look for this Planet. Our Solar System is really big, and it would take a significant amount of time to cover the entire sky region in which Planet Nine might be hiding.
• To further complicate things, there’s only a small window each year during which conditions are just right for this search.
• In 2021, a team using the Atacama Cosmology Telescope (a millimetre-wave radio telescope) published the results from their search for a ninth planet’s movement in the outskirts of the Solar System. While they weren’t able to confirm its existence, they provided ten candidates for further follow-up.

Why is it challenging to locate the planet?

Planets are difficult to locate because Planets emit very dim red wavelengths of light, so we can only see them clearly when they’re reflecting the light of their star. The farther away a planet is from its star, the harder it is to see.

What are exoplanet and challenges in finding them?

Even though we have telescopes that can reveal galaxies from the universe’s earliest years, we still can’t easily directly image planets outside of our Solar System, also called exoplanets.

• The reason is same as stated earlier. Planets emit very dim red wavelengths of light, so we can only see them clearly when they’re reflecting the light of their star. The farther away a planet is from its star, the harder it is to see.
• So astronomers came up with another way to find exoplanets: the transit method.

What is Transit method, and how it’s  used to locate exoplanet?

Transits reveal an exoplanet not because we directly see it from many light-years away, but because the planet passing in front of its star ever so slightly dims its light. This dimming can be seen in light curves – graphs showing light received over a period of time. When the exoplanet passes in front of the star, the light curve will show a dip in brightness.