This paper presents a comprehensive study of the physical properties of approximately 105 galaxies with measurable star formation in the SDSS (Sloan Digital Sky Survey). By comparing emission line data with continuum properties, the authors build a picture of star-forming galaxies at \( z < 0.2 \). They develop a method for aperture correction using resolved imaging, which removes aperture bias in star formation rate (SFR) estimates, allowing accurate determination of total SFRs in galaxies. The SFR density is determined to be \( 1.915 \pm 0.02 \) (rand.) \( \pm 0.14 \) (sys.) \( h^{-1} \) M⊙/yr/Mpc³ at \( z = 0.1 \) (for a Kroupa IMF). The study reveals that most star formation occurs in moderately massive galaxies (10^10−10^11 M⊙), typically in high surface brightness disk galaxies. About 15% of all star formation takes place in galaxies with some signs of an active nucleus, and 20% occurs in starburst galaxies. The present to past-average star formation rate, the Scala b-parameter, is almost constant over three orders of magnitude in mass, declining only at \( M_* > 10^{10} \) M⊙. The volume-averaged b-parameter is \( 0.408 \pm 0.005 \) (rand.) \( \pm 0.020 \) (sys.) \( h^{-1} \). Using this value, the authors constrain the star formation history of the universe, finding that the present-day universe is forming stars at least one-third of its past average rate, corresponding to a time-scale of \( T + 1.5 \) Gyr. The study also discusses the correlation between b and morphological type, as well as the tight correlation between the 4000 Å break (D4000) and b.This paper presents a comprehensive study of the physical properties of approximately 105 galaxies with measurable star formation in the SDSS (Sloan Digital Sky Survey). By comparing emission line data with continuum properties, the authors build a picture of star-forming galaxies at \( z < 0.2 \). They develop a method for aperture correction using resolved imaging, which removes aperture bias in star formation rate (SFR) estimates, allowing accurate determination of total SFRs in galaxies. The SFR density is determined to be \( 1.915 \pm 0.02 \) (rand.) \( \pm 0.14 \) (sys.) \( h^{-1} \) M⊙/yr/Mpc³ at \( z = 0.1 \) (for a Kroupa IMF). The study reveals that most star formation occurs in moderately massive galaxies (10^10−10^11 M⊙), typically in high surface brightness disk galaxies. About 15% of all star formation takes place in galaxies with some signs of an active nucleus, and 20% occurs in starburst galaxies. The present to past-average star formation rate, the Scala b-parameter, is almost constant over three orders of magnitude in mass, declining only at \( M_* > 10^{10} \) M⊙. The volume-averaged b-parameter is \( 0.408 \pm 0.005 \) (rand.) \( \pm 0.020 \) (sys.) \( h^{-1} \). Using this value, the authors constrain the star formation history of the universe, finding that the present-day universe is forming stars at least one-third of its past average rate, corresponding to a time-scale of \( T + 1.5 \) Gyr. The study also discusses the correlation between b and morphological type, as well as the tight correlation between the 4000 Å break (D4000) and b.