The doctrine that at least certain ideas (e.g., those of God, infinity, substance) must be innate, because no satisfactory empirical origin of them could be conceived, flourished in the 17th century and found in RenÃ© Descartes its most prominent exponent.
Local Curvature of Space. According to Einsteinâs theory of general relativity, massive objects warp the spacetime around them, and the effect a warp has on objects is what we call gravity. So, locally, spacetime is curved around every object with mass. Overall Curvature of Space
Astronomical spectroscopy. Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light and radio, which radiates from stars and other hot celestial objects. Spectroscopy can be used to derive many properties of distant stars and galaxies, such as their chemical composition, temperature, density, mass, distance, luminosity, and relative motion using Doppler shift measurements.