The Harappan Civilization is one of the oldest civilizations in ancient India, also known as the Indus Valley Civilization. The archaeological remains at various sites help us learn about the science, technology and innovation progress made by them as follows:

• Architecture and Civil Engineering: The Harappan Civilization cities were well-planned. Baked bricks were used to build houses in rows on both sides of the road.
  • The architecture of well-planned urban centers based on fixed-layout patterns with scientific roads, drainage systems (with the use of corbelled technology), and public structures (such as granaries and great bathwater) were far ahead of time and precursors to the modern concept of architecture and civil engineering.
  • They had a high level of knowledge about the water flow and the flow of tides evident from the construction of the world’s first tide port in Lothal.
• Transportation Technology: There has been evidence of the maritime trade network operating between the Harappan and Mesopotamian civilizations. This was possible due to knowledge of advanced boat technology. Further, archaeologists have discovered a vast, dry canal as a docking facility in the coastal city of Lothal.
• Irrigation System: They were the first to use complex multi-cropping strategies in both seasons, which required separate sorting management. Irrigation systems included artificial reservoirs (such as Girnar) and vast early canal systems.
• Knowledge of Metallurgy: They developed some new metallurgy techniques and produced copper, bronze, lead, and tin. In addition, a stone touching gold streaks was found at Banawali, which may have been used to test the purity of gold, a technique still used in parts of India today.
• Weight, Measurement, and Mathematics: They were among the first to develop a system of equal weights and measures. They followed the decimal measurements division for all practical purposes, including measuring mass by their hexahedron weights. They also had a weighing stone called Batkhara. Also, the Harappans were very modern in mathematics as evidenced from the use of decimal and additive multipliers.
• Medical Science: There has been evidence of the use of advanced medical technology like proto-dentistry (drilling of the tooth), Trephination (medical intervention of making a burr hole in the skull to treat migraines and mental disorders), etc. They also used various herbs and medicines to treat diseases.
• Pottery and jewel making: They were familiar with wheel-drawn potters. Paintings and glazing of potters were also known. They also learned to use lime as plaster and pyro-technology to heat lime. They had a good knowledge of furnaces and were experts in making beads. They knew the art of bead cutting, drilling, and polishing.
• Other significant inventions and discoveries:
  • Rod with copper-alloy strip was found at Nippur, which is claimed to have been used as a measurement standard (ruler).
  • Buttons were used for decorative purposes with some engraved in geometric shapes and pierced to be attached to clothing using a thread.
  • The earliest clear evidence of the origin of the well is found in the Mohenjo-Daro and Dholavira.

The Harappan civilization showed a level of sophistication and advancement not seen in other contemporary civilizations. They can rightly be considered as the real pioneers of science, technology, and innovation in India as many of their techniques and inventions still find relevance in contemporary times.

Aditya (Sanskrit for Sun), is a planned mission of ISRO to study the Sun. Earlier named as Aditya-1, Aditya-L1 shall be the first space-based Indian mission to study the Sun. The Polar Satellite Launch Vehicle (PSLV-XL) is scheduled to launch the Aditya-L1 in 2023 from Sriharikota, Andhra Pradesh.

Differences between Aditya-1 and Aditya-L1:

• Aditya-1:
• • Aditya-1 was planned to be launched in an 800km low earth orbit.
• It was envisioned to be a 400 kg class satellite carrying a single payload, the Visible Emission Line Coronagraph (VELC).
• It was initially limited to observing only the solar corona.
• Aditya-L1:
• 0 Since a satellite placed in the halo orbit around the first Lagrangian Point (L1) of the Sun-earth system has the major advantage of continuously viewing the Sun without any occultation/eclipses, the Aditya-1 mission was renamed as Aditya-L1 mission, which will be inserted in a halo orbit around the L1-1.5 million km from the earth towards the Sun.
• Against only one payload in Aditya-1, Aditya-L1 carries seven payloads.
• It aims to observe the photosphere, chromosphere, and the outermost layers of the sun (the corona) using electromagnetic particle and magnetic field detectors.
• The enhanced Aditya-L1 project would provide a thorough knowledge of the Sun’s dynamic processes and answer some significant problems in solar physics.

Scientific objectives of Aditya-L1:

• Study of solar upper atmospheric (chromosphere and corona) dynamics.
• Study of chromospheric and coronal heating, physics of the partially ionized plasma, initiation of the coronal mass ejections, and flares.
• Observe the in-situ particle and plasma environment providing data for the study of particle dynamics from the Sun.
• Real-time observation of solar activities and their impact on space weather.
• Understand how solar winds and coronal mass ejections affect the geomagnetic field of the Earth and its magnetosphere.
• Identify the sequence of processes that occur at multiple layers (chromosphere, base, and extended corona), which eventually leads to solar eruptive events.
• Diagnostics of the coronal and coronal loops plasma: temperature, velocity, and density.
• Magnetic field topology and magnetic field measurements in the solar corona.

Thus, the suits of Aditya L1 payloads are expected to provide the most crucial information to understand the problem of coronal heating, coronal mass ejection, pre-flare, and flare activities and their characteristics, dynamics of space weather, propagation of particles and fields, etc. The mission will capture near-simultaneous photos of the many layers of the Sun’s atmosphere, revealing how energy is routed and transported from one layer to the next.