How Far Away Are The Stars From Earth?

Stars have always been considered from a romantic and poetic perspective. But how far are stars? Do they really are so distant from us? And how can we measure such tremendous distances? Are there any valid techniques? A lot of surprising things can be said about these questions.
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Is it possible to calculate star distances? Definitely yes, but some further explanations must be clarified. Obviously, we can’t measure such a huge gap with the normal methods we are used to on earth. We must calculate distance in an indirect way. What does it mean? We need to measure two different quantities that are related to each other through distance; then, with a simple equation, we can easily derive how far the star is from us.
Let’s make an example: if we want to measure how many kilometers are there between two cities, we can drive at a constant velocity and measure directly how much time does the journey take. After that we can just get information about the distance.
Similarly, physicists utilize the different types of brightness of a star that depend on distance to know how far the star actually is.
Before going on more rigorously on this subject we must list the major units of measure used to identify the distance of a star.
The first one is astronomical unit, which is exactly the gap that separates Earth from the sun, corresponding to 1011 meters or 8 minute at the speed of light.
The other one is parsec, nearly around 1016 meters or 3,26 light years, which represents the distance that causes a change of one degree in the sky over an entire year. This phenomenon is also known as parallax, but we’ll discuss it later.
In order to understand the major techniques used in astronomical researches, we need to take a little step back and define some important physical quantities.
The first one is absolute luminosity, which is the radiation power of a light emitting object. Consider it as the measurement of its brightness: a small lamp has a lower luminosity than a lighthouse. Moreover, we can define another quantity that derives by the previous one and it is named apparent luminosity. It is proportional to the inverse of square distance. Shortly, apparent luminosity is higher when the star is closer and viceversa. A lighthouse is certainly brighter than a lamp, but if it’s 10 or 20 times more distant the lamp will “seem” having a greater power. Apparent luminosity is a sort of superficial density of power.
In parallel, physicists defined apparent magnitude which is greater when luminosity is lower and smaller when luminosity is higher. As a matter of fact, the brightest star visible from Earth, which is known as Vega, has a conventional value of zero. Obviously, it is dependent on distance and can be considered as an equivalent of apparent luminosity. In addiction, another quantity called absolute magnitude has been introduced by scientists: it measures the magnitude that all stars would have at a distance of 10 parsec.
Similarly to what we did before with velocity and time, astronomers usually utilize absolute and apparent magnitude to derive distance.
Since apparent magnitude can be measured through telescope observations, it is necessary to find objects that have a well-known absolute magnitude. These stars or galaxies are also called “standard candles” are they’re crucial for measuring distances of stars.
The first object that is very useful for this method is a cepheid. Its major characteristic is the emission of electromagnetic waves: its intensity varies with time according to specific laws.
How far can we find star distances thanks to this method? Around 1 kpc, just the closest ones can be detected using Cepheids as standard candles.
As opposed to this technique, there’s even another way of revealing star distances at this scale just by using geometric properties. Did you know that?
Its name is Parallax.
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Credits: Ron Miller
Credits: Nasa/Shutterstock/Storyblocks/Elon Musk/SpaceX/ESA
Credits: Flickr
Credits: ESO

Video Chapters:
00:00 Introduction
01:36 Calculating Star Distances
06:18 Parallax

#insanecuriosity #stars #astronomy

[InsaneCuriosity]

Hey Insane Curiosity Squad! If you liked the video, we would love for you to share it with your friends or on other social networks like Facebook, Reddit, Instagram, TikTok and Twitter, etc... (Since the algorithm is not cooperating in showing us to the public 😅). In just 30 seconds, you will greatly help our Channel to grow and improve future contents. A big thank you from all of us.

[AmateurHour]

Watching this outside with a great view of thousands of stars. Pretty cool.

[scottmonfort]

If you define "The Stars" as "the stars we can see from earth" ... this explaination only explains how we can measure distance, but does not explain how far they are ... the nearest star is 4.2 light years away ... but how far are all the stars we see with the naked eye, and how does that compare to the Milkyway?

[petroskefallinos]

VERY VERY VERY nicely explained! Subbed! :D

[InsaneCuriosity]

What do you guys think about this different Narrator?

[fernandochaves]

A really nice topic. I've read a little about the redshift, and how was discovered by accident. Also i heard the term parallax before, i believe. Be sure new and more precise techniques will be developed. And the big and advanced telescopes will be a big help. Thanks...

One question about the channel: where are you from?

[InsaneCuriosity]

correct pronunciation= Supernova Type 1 A

[msnman]

Wow I’m seeing stars closer then ever before

[kg]

Star explosion eventually leads to life which calls it “terrible explosion” not fair.

[Goiri]

When I have started listening something was wrong Haha..great movie as always

[lovebiebermurs]

Good video but i don't think there was enough explanation for the type of complicated subject matter you were tackling.

[MartinsMusic]

Would you be able to make a “Measuring star distances for dummies”? Maybe using miles or something? Hahahaha jk but I would have to watch this video a few times with an astronomy dictionary to understand it 😂

[jonasdegaard]

Hi, a strange question...but wich sound/music is used as background around min 10:00...thans a lot

[larrymerkle]

You asked for comments. OK. I've always wondered, ....how far away are the stars in the night sky. You asked the question but you never answered it. What you talked about is how to measure the distance. Yours is the kind of narrative that doesn't tell me. It gets all caught up in par secs, standard candles, etc. There are so many scientists who can't explain something without resorting to math. This is why the TV series How the Universe Works is so good: it uses plain narrative and doesn't go to math.

[donogolo]

very unuseful video! you just ended up talking too much jargon without answering the question which probably drew the attention of people to your page...HOW FAR ARE THE STARS FROM EARTH! If this was in an exam situation i'd give you a score of 3/10. Hit the nail on the head without talking too much jargon!

[williamsantos]

Who are you and what did you do to our official narrator?

[pwatsky]

The commentator needs to learn his script and pronunciations....Par Sec is correctly Para Sec isn't . Type one a Super Nova, not type i a. Come on guys.

[SirFreakShow]

Noooo where's the original narrator. Not complaining about this one though he sounds alright

[ididntgetthejoke]

And people here being so entitled, when we're just a fraction of a grain of sand in an infinite beach

[rochford]

By the time you reach the most distant star, you find you never left🤔❓