The universe is a big and interesting realm, full of surprises and mysteries that we are only now beginning to unravel. The Indian Space Research Organisation (ISRO) is one of the world's major organisations dedicated to expanding human knowledge and understanding of the universe and beyond. In this blog, we will explore some of ISRO's most recent discoveries and riddles of the galaxy, and how they are transforming our understanding of the universe.

Aditya-L1: A new sun on the Sun

Aditya-L1 is the first Indian observatory-class mission dedicated to studying the Sun's corona and chromosphere. The corona is the most visible layer of the Sun's atmosphere during a total solar eclipse. During a partial solar eclipse, the chromosphere is seen as a crimson ring below the corona. The corona and the chromosphere are both very active and complicated, and they both play an important part in solar activity and solar wind, which affect the Earth and the galaxy.

Aditya-L1 was launched by a PSLV-C51 rocket on September 2, 2023, from the Satish Dhawan Space Centre in Sriharikota. It is in a halo orbit around the Lagrangian point L1, which is a region of gravitational equilibrium between the Earth and the Sun located approximately 1.5 million kilometres from the Earth. Aditya-L1 may observe the Sun indefinitely from this vantage point, unaffected by the Earth or the Moon.

The solar coronagraph, a near UV imager, an X-ray spectrometer, a particle detector, a magnetometer, and a radio analyzer are among the seven scientific instruments on Aditya-L1. These instruments will give unique observations of the Sun's corona and chromosphere, as well as measurements of the solar irradiance, solar wind, magnetic field, and radio emissions.

Aditya-L1 is projected to improve our understanding of the Sun and its impact on Earth and the galaxy, as well as the solar cycle, solar flares, coronal mass ejections, space weather, and the formation of the solar system.

NISAR: A new eye on the Earth and the galaxy

NISAR, which stands for NASA-ISRO Synthetic Aperture Radar, is a cooperative mission between ISRO and NASA. It is a Low Earth Orbit observatory that will map the entire globe in 12 days and provide spatially and temporally consistent data to help scientists understand changes in Earth's ecosystems, ice mass, vegetation biomass, sea level rise, groundwater, and natural hazards such as earthquakes, tsunamis, volcanoes, and landslides. NISAR will also research the evolution of galaxies, stars, black holes, and other cosmic phenomena.

NISAR was launched from the Satish Dhawan Space Centre in Sriharikota on 14 July 2023 by an LVM3 (formerly known as GSLV Mk III) rocket. It is equipped with a dual-frequency (L and S band) radar capable of penetrating clouds and vegetation and providing high-resolution photographs of the Earth and galaxy. NISAR will also employ interferometry, a technology that integrates signals from many antennas to calculate changes in the distance between the satellite and the ground or the galaxy.

NISAR is projected to alter our understanding of the Earth and the cosmos, as well as give essential data for disaster management, climate change, agriculture, forestry, water resources, urban planning, archaeology, astronomy, and astrophysics.

X-ray polarimetry: A new look at black holes

X-ray polarimetry is a technique for measuring the polarisation of X-rays, which is the orientation of the X-ray photons' electric field. The physical features and geometry of X-ray sources such as black holes, neutron stars, pulsars, supernovae, and gamma-ray bursts can be revealed via polarisation.

Using the Polarimeter Instrument in X-ray (POLIX) onboard the AstroSat satellite, researchers from IIT Guwahati and ISRO recently found polarised X-rays from a black hole source beyond our Milky Way Galaxy. AstroSat is the first specialised Indian Astronomy satellite, launched by ISRO on September 28, 2015, that enables simultaneous multi-wavelength investigations of celestial bodies and cosmic sources in the X-ray and UV spectral regions.

The 4U 1630-47 black hole source is a binary system in which a black hole is accreting materials from a partner star. Polarised X-rays are released by the heated plasma around the black hole and are influenced by the black hole's powerful gravitational and magnetic fields. Polarisation can reveal information about the black hole's mass, spin, accretion rate, and magnetic field, as well as put gravity and magnetism theories to the test in extreme conditions.

X-ray polarimetry is a new and promising instrument for exploring the fundamental physics of the cosmos and probing the secrets of black holes and other unusual phenomena in the galaxy.

Conclusion

The universe is a big and intriguing realm, full of surprises and mysteries that we are only now beginning to unravel. The Indian Space Research Organisation (ISRO) is one of the world's major organisations dedicated to expanding human knowledge and understanding of the universe and beyond. In this blog, we looked at some of ISRO's most recent discoveries and riddles of the galaxy, and how they are transforming our understanding of the universe. We hope you found this blog interesting and learned something new and intriguing about the galaxy and ISRO. Keep an eye out for further updates from the galaxy and beyond!