I just read an article that said it took a star explosion light 13 billion years to reach earth. they said it was 400,000 years after the big bang. how do astronomers know how long ago a star exploded?How do astronomers calculate when a star exploded?Each element absorbs a specific set of color lines, which are like the fingerprint of the element. They measure the redshift of absorption lines in the spectrum. Then they apply Hubble's law; the distance is proportional to the redshift. The farther the source, the faster it moves away from us, so the more it's spectrum is shifted toward red.How do astronomers calculate when a star exploded?Many stars already have a known location/distance from Earth. All they need is the date and time the nova was first noticed and they can estimate the time it exploded by the distance. Say the star is one light year (l.y. = the distance light travels in a year = 5.88 x 10^12 miles) away and nova is noticed right now means it actually happened about a year ago.
.bh.How do astronomers calculate when a star exploded?zepero has the answerThe explanation is that light takes one full year to travel a distance of one light year.So what happened a year ago would reach us only now
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment