http://ift.tt/1nRQ1ve
Light from huge explosion 12 billion years ago reaches Earth.
How do they know its age? By knowing the distance? How do they know the distance it has traveled?
Some things I can see how scientists figured them out despite being billions of years removed. But some just leave me with "How do they know?
More "How do they know?" How do they know hydrogen was the first and omnipresent element? I think I understand how they know it formed helium but when is a mystery.
How do they know specific things happened at specific times? Perhaps they see it on incoming light waves? How do they know when the Big Bang happened and how long afterward certain things happened?
I keep telling myself that the answer is in light waves and they can measure those but didn't they first need distance data? They get that from knowing how fast light travels but how do they know how long that light has been traveling?
Enough hows? Day has dawned. That I know. Good morning.
Light from huge explosion 12 billion years ago reaches Earth.
How do they know its age? By knowing the distance? How do they know the distance it has traveled?
Some things I can see how scientists figured them out despite being billions of years removed. But some just leave me with "How do they know?
More "How do they know?" How do they know hydrogen was the first and omnipresent element? I think I understand how they know it formed helium but when is a mystery.
How do they know specific things happened at specific times? Perhaps they see it on incoming light waves? How do they know when the Big Bang happened and how long afterward certain things happened?
I keep telling myself that the answer is in light waves and they can measure those but didn't they first need distance data? They get that from knowing how fast light travels but how do they know how long that light has been traveling?
Enough hows? Day has dawned. That I know. Good morning.
via JREF Forum http://ift.tt/1pHSJmZ
Aucun commentaire:
Enregistrer un commentaire