A Beginner’s View of the Universe (Ongoing Notes from an Astronomy student and lazy Amateur Astronomer)

 

Hi all,

As some of you know, I’m currently studying astronomy at the University of Lancashire. Coming to this later in life has been both challenging and genuinely fascinating — there’s something quite humbling about realising how much there is to learn about the universe.

Rather than writing separate posts every time I come across something interesting, I thought I’d try something different: a single, evolving post that I’ll keep updating as I go.

This will be a mix of:

• things I’m learning
• observations from my own imaging
• and the occasional “10 things about…” style notes

I’ll update this regularly, so feel free to check back in from time to time.

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🔭 Current Setup

I’m using a Seestar S30, which has been a great entry point into imaging.

So far I’ve been using it for:

• Solar imaging
• Lunar shots
• Deep Sky Objects (DSOs)

It’s surprisingly capable for something so compact, and ideal for someone like me who’s still learning the ropes without wanting to get buried in overly complex setups (yet).

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🌌 The Vast Distances of the Universe

How Astronomers Measure the Cosmos

🚀 Introduction

Whenever we look up at the night sky, we're also looking back in time. The Moon appears as it was just over a second ago, the Sun as it was about eight minutes ago, and the nearest stars as they were years ago.

But how do astronomers measure distances that are far beyond the reach of a tape measure? The answer is a series of methods known as the Cosmic Distance Ladder. Each rung builds on the one before it, allowing us to measure ever greater distances across the Universe.

💡 The Speed of Light – Nature's Speed Limit

Everything begins with the speed of light.

Travelling at an incredible 299,792 kilometres per second (186,282 miles per second), light is the fastest thing in the Universe. It also provides astronomers with a convenient way of measuring distance.

Some familiar examples include:

🌍 Earth to the Moon: about 1.3 light-seconds

☀️ Sun to Earth: about 8 minutes 20 seconds

🌍 One light-year: the distance light travels in one year – approximately 9.46 trillion kilometres (5.88 trillion miles)

Because light takes time to travel, every astronomical observation is effectively a glimpse into the past.

📏 The Cosmic Distance Ladder

No single technique can measure every distance in space, so astronomers rely on several methods.

🛰️ Radar

Within our own Solar System, powerful radar signals are bounced off nearby planets and moons. Measuring the time taken for the signal to return gives an extremely accurate distance.

⭐ Parallax

For nearby stars, astronomers use Earth's orbit around the Sun. By observing how a star appears to shift against more distant background stars over six months, its distance can be calculated.

This method works well for relatively nearby stars and has been extended dramatically by the European Space Agency's Gaia mission.

✨ Cepheid Variable Stars

Further out, astronomers use special stars whose brightness changes in a regular pattern. The longer the period of variation, the brighter the star really is.

By comparing a Cepheid's true brightness with how bright it appears from Earth, its distance can be determined.

💥 Type Ia Supernovae

When certain white dwarf stars explode, they all reach almost exactly the same peak brightness.

These spectacular explosions act as "standard candles", allowing astronomers to measure distances to galaxies billions of light-years away.

🌌 Redshift

Beyond the reach of supernovae, astronomers study the light from distant galaxies.

As the Universe expands, the wavelength of light stretches towards the red end of the spectrum. The greater the redshift, the farther away the galaxy is and the faster it is receding.

🌠 The Expanding Universe

One of the greatest discoveries of the twentieth century was that the Universe itself is expanding.

Rather than galaxies flying through empty space, space itself is stretching, carrying galaxies farther apart over time.

This relationship was discovered by Edwin Hubble and explains why more distant galaxies appear to move away faster than nearby ones.

It also means that the farther we look into space, the farther back in time we see.

⏳ Looking Back in Time

Light from the Moon takes just over a second to reach us.

Light from the Sun takes a little over eight minutes.

The light from the Andromeda Galaxy has travelled for around 2.5 million years before reaching Earth.

The oldest light we can detect has been travelling for almost 13.8 billion years, allowing us to look back to a time when the Universe was incredibly young.

During that immense journey, the Universe has continued to expand, so the galaxies that emitted that ancient light are now far more distant than they were when the light began its journey.

🔭 Final Thoughts

I find the Cosmic Distance Ladder one of the most fascinating ideas in astronomy. It demonstrates how scientists combine several clever techniques to build a picture of a Universe so vast that our everyday experience simply can't prepare us for its scale.

From timing radar echoes within our Solar System to measuring the redshift of galaxies billions of light-years away, every rung of the ladder extends our reach a little further into the cosmos.

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🚀 Escape Velocity: How Fast Is Fast Enough?

Escape velocity is the minimum speed an object needs to break free from a planet, moon, star, or other body's gravity without needing any further propulsion.

In simple terms:

Go too slowly, and gravity pulls you back.

Reach escape velocity, and you can leave for good.

🧮 The Maths

The formula for escape velocity is:

v = √(2GM / R)

Where:

- v = escape velocity

- G = gravitational constant

- M = mass of the planet or object

- R = radius from the centre of that object

The important idea is that escape velocity depends on two things:

Mass and size.

A more massive object has stronger gravity. A smaller, more compact object also has stronger gravity at its surface. That is why dense objects can have extremely high escape velocities.

🌍 Earth

Earth's escape velocity is about:

11.2 km/s

That is roughly 40,000 km/h or 25,000 mph. A rocket leaving Earth must eventually reach at least this speed to escape Earth's gravity completely.

🔵 Neptune

Neptune is much more massive than Earth, so its escape velocity is higher:

23.5 km/s

That is more than twice Earth's escape velocity. Even though Neptune is a gas giant with no solid surface like Earth, its gravity is still strong enough that escaping from it requires enormous speed.

🕳️ Black Holes

A black hole takes this idea to the extreme. At the event horizon, the escape velocity becomes equal to the speed of light. But nothing can travel faster than light. That means once something crosses the event horizon, it cannot escape. Not even light.

This is why black holes appear black.

🌌 Final Thought

Escape velocity is a beautifully simple idea with huge consequences.

It explains why rockets need so much energy, why planets hold onto atmospheres, and why black holes are among the most extreme objects in the universe.

Sometimes a single equation can reveal something profound about how the cosmos works.

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📏 The Cosmic Distance Ladder – How We Measure the Universe

When your tape measure only reaches a few metres, how do you measure a galaxy?

🌌 Looking Into the Darkness

One of the questions that kept occurring to me when I first became interested in astronomy was surprisingly simple:

How do astronomers actually know how far away things are?

When I look at Jupiter through my telescope, how do we know it is hundreds of millions of kilometres away?

How do we know the Orion Nebula is over a thousand light years distant?

And how can anyone possibly claim that a galaxy is tens of millions of light years away when nobody has ever travelled there?

As it turns out, astronomers don't use one method.

They use a series of methods, each building upon the previous one.

This system is known as the Cosmic Distance Ladder.

🪜 Why a Ladder?

Imagine trying to measure the height of a mountain.

You can't simply stretch one tape measure from the ground to the summit.

Instead, you might measure one section, then another, gradually building up the total distance.

Astronomers do exactly the same thing.

One technique works nearby.

Another works farther away.

A third works for distant galaxies.

Each rung of the ladder helps calibrate the next.

🌍 The First Rung – Parallax

If you hold your thumb out at arm's length and close one eye, then switch eyes, your thumb appears to move against the background.

This effect is called parallax.

Earth itself provides astronomers with a giant measuring baseline.

By observing nearby stars six months apart—when Earth is on opposite sides of its orbit—the apparent movement of the star can be measured.

The tiny shift reveals the star's distance.

Parallax works extremely well for nearby stars, but eventually the shifts become so small that they are almost impossible to detect.

Even with modern satellites like Gaia, there are limits.

✨ Standard Candles

If you know how bright a light bulb really is, you can estimate how far away it is by how dim it appears.

Astronomers use certain stars in exactly this way.

These objects are called standard candles.

The most important are Cepheid variable stars.

Their brightness changes in a regular pattern, and the length of their cycle reveals their true luminosity.

Once astronomers know how bright the star actually is, comparing it to how bright it appears tells them the distance.

These stars allowed astronomers to measure nearby galaxies for the first time.

💥 Supernovae – Measuring Entire Galaxies

Some exploding stars behave remarkably consistently.

Type Ia supernovae reach nearly identical peak brightnesses.

Because they are so bright, they can be seen across enormous distances.

By comparing their true brightness to what we observe, astronomers can determine distances to galaxies hundreds of millions or even billions of light years away.

These stellar explosions became one of the most important tools in modern cosmology.

In fact, observations of distant supernovae helped reveal that the universe is expanding faster and faster.

🌌 Galaxies as Distance Markers

At even greater distances, astronomers examine entire galaxies.

Relationships between galaxy rotation speeds, sizes, and brightness allow estimates of their distances.

Eventually, astronomers rely on the expansion of the universe itself.

Because space is expanding, distant galaxies appear to move away from us.

The farther away a galaxy is, the faster it recedes.

This relationship is known as Hubble's Law.

The redshift of a galaxy's light provides clues to its distance.

🔭 Why This Matters to Amateur Astronomers

When I image objects such as the Orion Nebula or the galaxy M109, the numbers involved become difficult to comprehend.

The Orion Nebula lies around 1,300 light years away.

M109 is roughly 83 million light years distant.

The photons reaching my telescope tonight began their journeys long before humans built cities, invented writing, or even existed in our modern form.

The cosmic distance ladder is how we know those numbers.

It is one of humanity's greatest scientific achievements.

🧠 One of Science's Greatest Accomplishments

Nobody has travelled to another galaxy.

Nobody has carried a measuring tape across the stars.

Yet through geometry, physics, careful observation, and generations of astronomers building upon one another's work, we have constructed a ruler that stretches across the universe.

Each rung of the distance ladder depends upon the one below it.

Nearby stars help measure variable stars.

Variable stars help measure galaxies.

Galaxies help measure the expansion of the universe.

It is a beautiful example of science building knowledge step by step.

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🚀 Why You Can't Travel at the Speed of Light

It's not just difficult. It's impossible.

🌌 One of the most common questions in science fiction is simple:

"Why can't we just build a faster spaceship and eventually reach the speed of light?"

After all, light travels at an incredible 299,792 km/s (186,282 miles/s). At that speed you could circle Earth more than seven times in a single second. Yet according to Einstein's theory of relativity, there is a fundamental problem.The closer an object with mass gets to the speed of light, the more energy it requires to keep accelerating.

At first the increase is manageable. Then it becomes enormous.

As you approach the speed of light, the required energy rises toward infinity and infinite energy is something our universe simply doesn't provide.

🔬 Einstein's Unbreakable Rule:

In everyday life we assume that if you want to go faster, you simply use more fuel.

Cars do it.

Aircraft do it.

Rockets do it.

But the universe changes the rules when velocities become extremely high.Einstein showed that as an object's velocity approaches the speed of light, its relativistic effects become more and more extreme.

The result?

A spacecraft could get closer and closer to light speed...

But it could never actually reach it.

Not 100%.

Not even 99.999999999%.

Only closer and closer forever.

🌠 Looking Out Into Space:

One of the things I enjoy about amateur astronomy is that it constantly reminds me how vast the universe really is.

The objects in the following photographs are unimaginably distant, yet the light from them is still governed by the same cosmic speed limit.

🔭 M109 – A Galaxy 83 Million Light Years Away

This spiral galaxy, known as M109, lies approximately 83 million light years from Earth.

The light captured in this image began its journey before humans even existed in anything like our modern form.

That faint glow has been travelling through intergalactic space at the maximum speed allowed by nature for tens of millions of years before finally arriving at my telescope.

🪐 Jupiter and Its Moons

Even objects within our own solar system help demonstrate the scale of space.

This image shows Jupiter alongside several of its largest moons.

Although Jupiter is one of our nearest planetary neighbours, its light still takes around 30 to 50 minutes to reach Earth depending on where the planets are in their orbits.

Nothing carrying mass can beat that signal.

🌌 The Orion Nebula:

The Orion Nebula is one of the most spectacular sights in the winter sky.

Located around 1,344 light years from Earth, it is an active stellar nursery where new stars are still being born.

Every photon captured in this image has travelled for more than a millennium before reaching my telescope.

And even travelling at light speed, it still took over a thousand years.

 My favourite-Kepler's 3 laws

🌌 The Discovery That Changed Astronomy

In the early 1600s, Johannes Kepler transformed our understanding of the Solar System by discovering three mathematical laws that describe how planets move around the Sun. His work replaced centuries of assumptions and became the foundation of modern astronomy.

🪐 Law One: Orbits Are Ellipses

Kepler showed that planets do not travel in perfect circles. Instead, they follow elliptical paths with the Sun located at one focus of the ellipse. This explained why planets are sometimes closer to the Sun and sometimes farther away.

⚡ Law Two: Planets Change Speed

A planet moves faster when it is closer to the Sun and slower when it is farther away. This means planetary motion is constantly changing rather than remaining at a fixed speed.

⏳ Law Three: Farther Means Longer

The farther a planet is from the Sun, the longer it takes to complete an orbit. This relationship helps astronomers calculate orbital periods throughout the Solar System and around distant stars.

🚀 Why Kepler Still Matters

Kepler's laws are still used today to predict planetary positions, guide spacecraft, and study exoplanets. More than 400 years after their discovery, they remain among the most important ideas in astronomy.

☀️ 10 Things About the Sun

1. The Sun accounts for about 99.8% of the mass in the entire solar system.
2. It’s around 4.6 billion years old — roughly halfway through its life.
3. The core temperature is about 15 million °C.
4. Light from the Sun takes about 8 minutes to reach Earth.
5. The Sun is mostly hydrogen and helium.
6. Nuclear fusion in the core converts hydrogen into helium.
7. Sunspots are cooler areas caused by magnetic activity.
8. Solar flares can disrupt communications on Earth.
9. The Sun has an 11-year activity cycle.
10. One day, it will expand into a red giant.

(I’ll add more sections like this over time for other objects.)

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🌙 Recent Observations – Moon

[Update this section regularly]

I have spent some time capturing the Moon recently using my SeeStar S30.

Conditions were:

• Seeing: Fair to Good (≈ 5–7/10)
• Transparency: Moderate
• Conditions: A relatively stable evening with some high-level haze at times. Seeing was decent enough for lunar detail, though not perfectly steady — occasional atmospheric shimmer noticeable at higher magnifications.

What stood out most was the level of surface detail — craters and shadow contrast were particularly sharp.

Things I’m learning:

• Timing really matters (early vs late phase)
• Even small changes in conditions make a big difference

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🌌 Deep Sky Objects (DSOs)

[Ongoing section]

I’ve started experimenting with DSOs — still early days.

Targets so far:

• IC1318
• M31
• M42
• M101

Challenges:

• Light pollution
• Tracking limitations
• Processing (still learning!)

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🧠 Things I’m Learning (and Re-learning)

• Patience matters more than equipment
• Conditions often matter more than settings
• You don’t need perfect gear to get started
• Half the battle is just going outside and trying

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🔄 This Post Will Evolve

I’ll keep updating this with:

• new observations
• new images
• short “10 things about…” sections (planets, galaxies, etc.)

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❓ Question

For those of you interested in space or photography:

What would you like me to try and capture next — the Moon, planets, or more deep sky objects?

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More updates soon.