The Times Australia
The Times World News

.

why do we see the 'sky' during the day, but the galaxy at night?

  • Written by Hannah Schunker, Lecturer of Physics, University of Newcastle

Why do we see the sky during the day, but the galaxy at night? — Gary, age 9, Auckland

why do we see the 'sky' during the day, but the galaxy at night?

Hi Gary! Thank you for this great question.

To put it simply, the reason the sky looks different to us between daytime and nighttime is mostly because of our atmosphere.

The atmosphere surrounds Earth, and extends from the ground to outer space. It’s made of different gases including oxygen (which keeps us alive as we breathe it in), carbon dioxide (which we breathe out), methane (which is also in our farts), nitrogen and argon.

All these gases, as well as all solids and liquids, are made of molecules. Molecules are collections of atoms which are much too small for us to see, but are the basic building blocks of everything that exists. Importantly, different molecules have different combinations of atoms and come in different sizes.

A molecule’s size plays a role in how the molecule interacts with light. Light from the Sun isn’t one colour — it’s made up of all the colours of the rainbow (which is why we see a rainbow when light behaves in a certain way).

Some of the molecules in Earth’s atmosphere are just the right size that the blue part of the light from the Sun bounces off them, scattering in different directions.

So when we look towards the Sun during the day (remembering that you should never look directly at the Sun), we see rays of light that have come from the Sun straight down to us.

But when we look away from the Sun we see the blue light rays scattering from the part of the atmosphere we are looking at. That’s why the sky is so bright — and blue — during the day.

The galaxy at night

At night we see stars in a dark sky, and these stars make up our galaxy, the Milky Way. The Milky Way is made of a huge number of stars, including the Sun.

Galaxy sky at night
The Milky Way contains all the stars in our galaxy, and each of these stars might have orbiting planets, just like the Earth orbits the Sun. Shutterstock

Compared with other stars, the Sun actually isn’t that bright, but it looks very bright to us because it’s much closer to Earth than other stars are.

At night, when your side of Earth is facing away from the Sun, the only light that reaches you is from other stars. This starlight also scatters off molecules in the atmosphere, but as there’s less of it, not much scattering goes on.

This is why, at night when we’re facing away from the Sun, we don’t see the same thing as when we are facing the Sun during the day. Instead, we can look through the atmosphere and beyond at the big, dark expanse of space around us and the many, many faraway stars in our galaxy.

Read more: Curious Kids: how does the Sun make such pretty colours at sunsets and sunrises?[1]

The sky on other planets

Other planets in our Solar System have different molecules in their atmosphere compared with Earth, which means their skies look different during the day and night.

The atmosphere on Venus, for example, is so thick you would never see the Sun — not even during the day when you were facing towards it. The stars are not visible at night, either.

Astronauts who are above our atmosphere, such as on the International Space Station or on the Moon, don’t see the bright blue sky we see on Earth. Instead, they see the Sun as a large nearby star against a black sky.

And they can see the galaxy all the time.

Astronauts onboard the International Space Station can get a great view of the Sun in ‘starburst’ mode over Earth. NASA[2]

Read more https://theconversation.com/curious-kids-why-do-we-see-the-sky-during-the-day-but-the-galaxy-at-night-170096

Times Magazine

Building a Strong Online Presence with Katoomba Web Design

Katoomba web design is more than just creating a website that looks good—it’s about building an online presence that reflects your brand, engages your audience, and drives results. For local businesses in the Blue Mountains, a well-designed website a...

September Sunset Polo

International Polo Tour To Bridge Historic Sport, Life-Changing Philanthropy, and Breath-Taking Beauty On Saturday, September 6th, history will be made as the International Polo Tour (IPT), a sports leader headquartered here in South Florida...

5 Ways Microsoft Fabric Simplifies Your Data Analytics Workflow

In today's data-driven world, businesses are constantly seeking ways to streamline their data analytics processes. The sheer volume and complexity of data can be overwhelming, often leading to bottlenecks and inefficiencies. Enter the innovative da...

7 Questions to Ask Before You Sign IT Support Companies in Sydney

Choosing an IT partner can feel like buying an insurance policy you hope you never need. The right choice keeps your team productive, your data safe, and your budget predictable. The wrong choice shows up as slow tickets, surprise bills, and risky sh...

Choosing the Right Legal Aid Lawyer in Sutherland Shire: Key Considerations

Legal aid services play an essential role in ensuring access to justice for all. For people in the Sutherland Shire who may not have the financial means to pay for private legal assistance, legal aid ensures that everyone has access to representa...

Watercolor vs. Oil vs. Digital: Which Medium Fits Your Pet's Personality?

When it comes to immortalizing your pet’s unique personality in art, choosing the right medium is essential. Each artistic medium, whether watercolor, oil, or digital, has distinct qualities that can bring out the spirit of your furry friend in dif...

The Times Features

NSW has a new fashion sector strategy – but a sustainable industry needs a federally legislated response

The New South Wales government recently announced the launch of the NSW Fashion Sector Strategy, 2025–28[1]. The strategy, developed in partnership with the Australian Fashion ...

From Garden to Gift: Why Roses Make the Perfect Present

Think back to the last time you gave or received flowers. Chances are, roses were part of the bunch, or maybe they were the whole bunch.   Roses tend to leave an impression. Even ...

Do I have insomnia? 5 reasons why you might not

Even a single night of sleep trouble can feel distressing and lonely. You toss and turn, stare at the ceiling, and wonder how you’ll cope tomorrow. No wonder many people star...

Wedding Photography Trends You Need to Know (Before You Regret Your Album)

Your wedding album should be a timeless keepsake, not something you cringe at years later. Trends may come and go, but choosing the right wedding photography approach ensures your ...

Can you say no to your doctor using an AI scribe?

Doctors’ offices were once private. But increasingly, artificial intelligence (AI) scribes (also known as digital scribes) are listening in. These tools can record and trans...

There’s a new vaccine for pneumococcal disease in Australia. Here’s what to know

The Australian government announced last week there’s a new vaccine[1] for pneumococcal disease on the National Immunisation Program for all children. This vaccine replaces pr...