sci_phy
Space and the Universe Space - Solar System, Stars, and the Big Bang
Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.
Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.
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Physics · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)
Summary
Inner planets (Mercury, Venus, Earth, Mars) are small and rocky. Outer planets (Jupiter, Saturn, Uranus, Neptune) are huge gas or ice giants. Farther planets orbit more slowly.
A Sun-sized star ends as a red giant then a white dwarf. A much bigger star explodes as a supernova, leaving a neutron star or black hole.
Light waves are stretched to longer wavelengths as galaxies recede. The further the galaxy, the bigger the red-shift (Hubble's law).
The cosmic microwave background (CMB) is the cooled afterglow of that hot start, found in every direction. It is strong evidence for the Big Bang.
Hard words & meanings
| light year | the distance light travels in one year, about 9.46 x 10^15 m |
| nebula | a cloud of gas and dust in space where stars are born |
| main sequence | the long, stable stage of a star's life when it fuses hydrogen |
| supernova | the explosion of a massive star at the end of its life |
| red-shift | the stretching of light to longer wavelengths from a source moving away |
| Hubble's law | the rule that a galaxy's recession speed is proportional to its distance, v = H0 d |
| Big Bang | the theory that the universe began ~13.8 billion years ago from a hot dense state and expanded |
| CMB | cosmic microwave background - faint microwave radiation left over from the early universe |
Model exam answers, grammar & audio
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