How do we know that the universe is infinitely expanding?
In: Physics
Think of an ambulance. Racing towards u its higher pitched but as soon as it goes past its lower pitched. Thats the frequency change with speed.
Same with light. If its moving away….more red. If moving towards…..more blue. Everything is pretty much looking red so its all moving away like an expanding bubble.
Thats seriously oversimplified but hope it helps.
We can figure whether astronomical object (galaxies or stars) are moving towards us or away from us by seeing the shift in the wavelength of light coming from the objects.
It’s called a Red shift if the objects are – moving away from us
And a Blue shit if the objects are – moving towards us
Keep this concept in mind, I’ll corelate it with something you’ve experienced.
So mostly the light shift has to do with the spectrum of rainbow 🌈
VIB-GY-OR
Violet has short wavelength and red has long wavelength
So when a object is moving away from us, the Normal light from the objects takes longer to reach us and hence is stretched or elongated and appear red in color. #Red ➡️ long wavelength
The opposite happens when the object is moving towards us. The Normal/regular light from the object gets compressed or shortened. # Blue➡️ short wavelength
The same can be experienced when an ambulance 🚑 passes by you – you hear the high pich sound (whaaan) as it approaches (compressed)(corelate to the compressed short wavelength blue shift), and you hear a low pitch sound (wooon) when it travels away from us (stretched/elongated)(long wavelength red shift)
Just imagine the whole experience of an ambulance passing.
High pitch <- Whaaannnnnnnn(You)Wooooooooooo -> low pitch, long wavelength
This example with sound is called the Doppler shift
And using the former(red/blue shift) we observe the astronomical objects and find that they are red shifted and are accelerating at a tremendous rate away from us.
Hence the expansion of space/universe
The crazy part is that as the objects move away from us, more and more space is just created inbetween.
The space is expanding like how a balloon 🎈 inflates.
Gotta go and sleep. Good night people. Pardon the errors, and warm love from India
We know that the universe is expanding, we don’t know that it will go on for ever doing so, there is a possibility that the universe will collapse in the far future in a big crunch. However with the current velocity that parts of the universe are travelling getting it all back together in one place might be unlikely.
We can measure two important things about an astronomical body (star, planet, etc.)
– it’s speed
and
-whether it’s moving toward or away from us
If you measure these aspects of most things (other than those very close to us) we can see that most things in the universe are moving away from us. Since bodies in space don’t change direction on their own, the theory is that everything started at a single point in space and is continually moving outward. We theorize it is expanding because most of what we see is moving further away each year.
Latest Answers