@tinderness maybe this https://news.osu.edu/the-stuff-of-the-universe-keeps-changing/?utm_source=College+of+Arts+and+Sciences&utm_campaign=acf6652da6-EMAIL_CAMPAIGN_2018_10_25_08_27_COPY_01&utm_medium=email&utm_term=0_112a361dc0-acf6652da6-322755809 for your first question?

For your second: the Earth is part of the solar system - it comprises the Sun and all the things orbiting it (including all the planets, one of them being the Earth!), so the above is also the origin of elements here on Earth :)