Technology that changed our view of the universe
AC9S10H02 AC9S10U03 AC9S10I08
By the end of this lesson you should be able to
- Give examples of technology enabling science, and science enabling new technology.
- Describe what at least three astronomical technologies could do that earlier tools could not.
- Identify a limitation of each technology.
- Critically analyse a development, ending with a judgement supported by reasons.
Hook
Without technology, what could you know about the sky? Make a quick list with a partner of everything you could find out about the universe using only your eyes, a notebook and a lot of patience.
Now cross out everything on today's "big bang evidence" list that you could NOT have found that way. (Hint: all of it.)
Every one of those discoveries needed a machine that did not exist 150 years ago. And many of those machines needed science to build them. Today: technology enables science, and science enables technology.
Watch: Telescopes: Crash Course Astronomy #6 · Crash Course
A two-way street
Technology enables science: a new tool lets scientists observe things nobody could see before. Galileo's telescope showed moons going around Jupiter. Radio dishes found the cosmic microwave background.
Science enables technology: scientific understanding lets engineers build new tools. Newton understood that a lens splits white light into colours (blurring images), so he designed a telescope that uses a mirror instead. Understanding infrared light made the James Webb Space Telescope possible.
This feedback loop keeps going: new tool → new discoveries → new understanding → better tools.
Key idea: most big changes in our picture of the universe came soon after a new kind of instrument, or the same instrument made much bigger or moved into space.
This NASA image shows the whole electromagnetic spectrum and which parts three space telescopes observe. Different tools see different kinds of light. Our atmosphere blocks most of the spectrum: there are only two clear windows: visible light and radio waves. That is why the eye, Galileo's telescope and radio dishes such as Parkes work from the ground, while X-ray, ultraviolet and most infrared telescopes (such as JWST) have to go into space. Planck went to space to measure the microwave background without the atmosphere getting in the way.
A timeline of technology
| Year | Development | What it let us see |
|---|---|---|
| about 130 BCE | Hipparchus's star catalogue (by eye) | About 850 stars and their brightness |
| about 1020 | Ibn al-Haytham's experiments on light and vision | How light, lenses and mirrors work |
| 1668 | Newton's reflecting telescope | Sharper images; mirrors can be made much bigger than lenses |
| 1880s | Photographic sky surveys | Stars far too faint for the eye, recorded over hours |
| 1912 | Leavitt's Cepheid distances | How far away stars and galaxies are |
| 1932 | Jansky detects radio waves from the Milky Way | The universe in radio waves |
| 1961 and 1969 | CSIRO's Parkes 64 m dish; Apollo 11 TV relay | Radio sources across the southern sky |
| 1995 | First planet found around a Sun-like star | Planets around other stars |
| 2013–2025 | Gaia space telescope | Positions, distances and motions of about 2 billion stars |
| 2015 | LIGO detects gravitational waves | Merging black holes, through ripples in space itself |
| 2019 | Event Horizon Telescope's first black hole image | The shadow of a black hole |
| 2025 | Vera C. Rubin Observatory first images | The whole southern sky every few nights: things that change |
- Before telescopes: Hipparchus (~130 BCE) catalogued about 850 stars by eye, with a brightness scale still used today. Ibn al-Haytham (~1020) showed by experiment that we see because light enters the eye, and studied lenses and mirrors: the science behind every telescope.
- 1668, Newton's reflector; 1880s, photographic surveys: mirrors can be made far bigger than lenses, and photographic plates collect light for hours, recording stars far too faint for any eye.
- 1912, Henrietta Leavitt: working from thousands of photographic plates, found that Cepheid stars can be used to measure distance.
- 1932–1969, radio astronomy: Karl Jansky detected radio waves from the Milky Way. CSIRO's Parkes 64 m dish in NSW (1961) mapped radio sources and relayed TV of the Apollo 11 moonwalk (1969).
- 1995, the first planet around a Sun-like star: found by measuring the star's tiny back-and-forth Doppler shift as the planet tugs on it. Today more than 5000 exoplanets are known.
- 2013–2025, Gaia and 2025, Rubin: Gaia measured positions, distances and motions of about 2 billion stars from space. The Vera C. Rubin Observatory (Chile) will photograph the whole southern sky every few nights for 10 years, catching things that change.
- 2015, LIGO and 2019, the Event Horizon Telescope: brand-new ways to observe. LIGO detected gravitational waves (ripples in space itself) from merging black holes. The EHT linked radio dishes around the world into one Earth-sized telescope to image the shadow of a black hole.
How to critically analyse a development
To critically analyse means to look at both the strengths and the weaknesses, then make a supported judgement. Five steps:
- Identify the technology (what is it, when?).
- New ability: what could it do that earlier tools could not?
- What it showed: what did we learn? Did it confirm, change or overturn earlier ideas?
- Limitations: what could it NOT do? What problems or uncertainties did it have?
- Judgement: how important was it, compared with other developments? Give reasons.
A strong answer is balanced (not just praise) and its judgement follows from the evidence. Words like "proved" are rarely accurate: one instrument usually provides strong evidence that, together with other evidence, changes scientists' minds.
Worked example: Newton's reflecting telescope (short version)
Critically analyse the importance of Newton's reflecting telescope.
Identify: a small telescope Isaac Newton built in 1668 that used a curved mirror instead of a lens to collect light.
New ability: lenses split white light into colours, giving blurry, rainbow-edged images. A mirror reflects all colours the same way, so the images are sharper. Mirrors can also be supported from behind, so they can be made much bigger than lenses.
What it showed: Newton's own telescope (with a mirror about 3 cm across) made no big discoveries. But it showed the design worked, and it was based on his science of light and colour. Reflectors grew bigger and bigger: William Herschel discovered Uranus with one in 1781, and every large telescope today is a reflector.
Limitations: early mirrors were made of polished metal that reflected only about two-thirds of the light, tarnished quickly and were hard to shape accurately. This was not fixed until silver-coated glass mirrors in the 1850s.
Judgement: small immediate impact, but enormous long-term impact: it made today's giant telescopes possible. It is also a clear case of science enabling technology: Newton's understanding of colour led to a better design.
Strengths, limitations, impact
Pick three events from the timeline table in section 2: one before 1900, one from 1900–1994, and one from 1995 onwards. Copy and complete this table.
| Event and year | New ability | What it showed (confirmed / changed / overturned?) | Limitations | Impact rating (1–5) |
|---|---|---|---|---|
Then write a judgement (3–4 sentences): which of your three changed our understanding of the universe the most? Compare it with at least one of the others, and give reasons.
Try it
Same sky, different light: on ESA's or NASA's Webb site, find an object imaged by both Hubble and JWST (the Pillars of Creation and the Carina Nebula are good ones). Put them side by side.
- What can you see in the JWST (infrared) image that is hidden in the Hubble (visible) image?
- Is there anything Hubble shows better?
This is the same idea as section 1: different kinds of light show different things.
NASA: James Webb Space Telescope images · ESA Webb: images · CSIRO: Parkes radio telescope (Murriyang)
Guided example
In 2019 the Event Horizon Telescope released the first image of a black hole's surroundings, in galaxy M87. Newspapers called it "the first photo of a black hole". Is that accurate? Use what the technology did and its limitations.
Show answer
What it did: eight radio observatories around the world were linked so they worked like one Earth-sized dish. That gave fine enough detail to see a glowing ring of hot gas around the black hole, with a dark centre where light cannot escape.
Limitations: it is not a photo in the normal sense. It is radio data from many telescopes, combined by computers into an image, and it needed years of processing and checking by independent teams. The black hole itself gives off no light: we see its shadow against the gas.
Judgement: "photo" is too simple, but the image was strong evidence: its size matched the prediction from Einstein's theory of gravity for a black hole of that mass. So it was a major step, as long as we describe it accurately.
Self-check
How this works
Pick an answer to get feedback. Nothing is saved or sent anywhere; this is just for you.
1.
Which is the best example of science enabling technology?
Explanation
Technology enables science (new tool → new discovery). Science enables technology (new understanding → new tool). JWST's infrared design depends on understanding infrared light.
2.
Why was putting the Hubble Space Telescope in orbit such an advantage over a ground telescope of the same size?
Explanation
Our atmosphere has only two clear windows: visible light and radio waves. It blocks ultraviolet, X-rays and most infrared, so telescopes for those wavelengths must go into space. Space telescopes cost much more and are hard to repair.
3.
The Gaia spacecraft (2013–2025) measured the positions and distances of about 2 billion stars using parallax. Which are genuine limitations of Gaia?
- Its parallax distances get less precise the farther away a star is
- It measured only a small fraction of our galaxy's stars, roughly 1%
- It could not measure distances at all, only colours
- It used the same parallax idea as Bessel in 1838, so it told us nothing new
Show answer
Correct: Its parallax distances get less precise the farther away a star is; It measured only a small fraction of our galaxy's stars, roughly 1%.
A good critical analysis names real limitations (what the technology can't do) as well as strengths.
4.
A student writes: "Gaia was the most important space mission ever, because it measured so many stars." Why is this a weak critical analysis?
Explanation
Critical analysis = new ability + what it showed + limitations + a judgement with reasons and a comparison. One fact, such as the number of stars, cannot support a judgement like "most important ever" by itself.
Exam skill: Critical analysis
What a full answer includes
- Identify the technology (what and when)
- New ability: what it could do that earlier tools could not
- What it showed: discoveries, and whether they confirmed, changed or overturned earlier ideas
- Limitations: what it could not do, problems or uncertainties
- Judgement: how important, with reasons and a comparison
- Aim for about 100–150 words: one clear point for each part is enough.
Worked example
Worked example (a non-astronomy case). Critically analyse how the light microscope changed our understanding of living things.
Identify: early microscopes of the 1600s, especially Robert Hooke's (1665) and Antonie van Leeuwenhoek's single-lens microscopes (1670s), which magnified up to about 270 times.
New ability: they showed objects far too small for the eye, below about 0.1 mm.
What it showed: Hooke saw tiny compartments in cork and named them "cells". Leeuwenhoek saw living single-celled organisms, bacteria, sperm cells and blood cells. Over the next 200 years, better microscopes led to cell theory (1830s–1850s): all living things are made of cells, and cells come from other cells. This overturned the idea that life could appear spontaneously from non-living matter and led to the germ theory of disease.
Limitations: early lenses gave blurry images with coloured fringes. Light microscopes cannot show anything smaller than about 0.2 µm, so viruses and the detail inside cells stayed hidden until the electron microscope (1930s). Specimens often had to be thin, stained or dead.
Judgement: one of the most important technologies in biology. It created the field of microbiology and made cell theory possible. But its impact took a long time: it needed better lenses, staining methods and many scientists' work, and the electron microscope was needed for the next big step. Its importance comes from opening up a whole new scale of life, rather than any single image.
Guided (use the prompts)
2.
Fact box
- Parkes is a 64 m radio dish run by CSIRO near Parkes, NSW. It opened in 1961.
- Radio waves pass through dust and cloud, and can be detected day and night.
- In 1962, Parkes pinpointed the position of a radio source called 3C 273. This let astronomers identify it as the first known quasar: the extremely bright core of a very distant galaxy.
- Parkes has discovered hundreds of pulsars (fast-spinning neutron stars).
- Limitations: radio waves are long, so a single dish makes much blurrier images than an optical telescope. Phones and satellites cause radio interference.
- Extra (optional): in 1969 Parkes relayed TV pictures of the Apollo 11 moonwalk.
Critically analyse the importance of the Parkes radio telescope. Use the fact box. Aim for 100–150 words.
- Identify it and the kind of light it detects.
- New ability: one thing radio waves let it do that visible light cannot.
- What it showed: one discovery.
- Limitation: one.
- Judgement: how important? Compare it with an optical telescope from the timeline.
Model answer
Parkes is CSIRO's 64 m radio dish in NSW, opened in 1961. It detects radio waves, which pass through dust and cloud, so it can study objects that visible light cannot reach and work day and night. In 1962 it pinpointed the radio source 3C 273, which let astronomers identify the first quasar, a hugely bright, distant galaxy core that optical telescopes had not recognised. It has also discovered hundreds of pulsars. Its main limitation is sharpness: radio waves are long, so its images are much blurrier than an optical telescope's, and phones and satellites cause interference. Overall it was very important. Newton's reflector made a familiar kind of light sharper, but Parkes opened a new window on the universe and revealed objects no one knew existed.
Your turn
3.
Fact box
- LIGO is two detectors in the USA, about 3000 km apart. Each uses lasers to measure the length of two 4 km arms extremely precisely.
- A passing gravitational wave (a ripple in space itself, predicted by Einstein in 1916) changes the arm length by less than the width of a proton.
- On 14 September 2015 both detectors recorded the waves from two black holes merging, about 1.3 billion light-years away. It won the 2017 Nobel Prize in Physics.
- Limitations: it can only detect very violent events, such as merging black holes or neutron stars. With only a few detectors, it cannot pinpoint exactly where in the sky a signal came from. Earthquakes and traffic cause noise.
Critically analyse how important LIGO is for our understanding of the universe. Use the fact box. Aim for 100–150 words.
Model answer
LIGO is two laser detectors in the USA that first recorded gravitational waves in 2015. Every earlier telescope detected some kind of light, but LIGO detects ripples in space itself, so it can study black holes, which give out no light. Its 2015 signal came from two black holes merging 1.3 billion light-years away. This provided strong evidence for Einstein's prediction of gravitational waves and showed that pairs of black holes really do merge. However, it can only detect very violent events, and it cannot pinpoint where in the sky a signal came from, so other telescopes are needed to find the source. Overall it is very important. Like Parkes, it opened a completely new window on the universe, but it studies a narrower range of events than telescopes that observe light.
Exit questions
- Give one example of technology enabling science from today's timeline, and explain it in one sentence.
- What could radio telescopes detect that optical telescopes could not?
- Write the five parts of a critical analysis.
Show answers
- e.g. Leavitt's photographic plates let her find the Cepheid distance method; the Parkes dish detected radio sources that optical telescopes missed; Gaia measured distances to about 2 billion stars; LIGO detected gravitational waves from merging black holes.
- Radio waves from objects hidden behind dust, cold hydrogen gas, pulsars, quasars and the CMB, and they work in daytime and through cloud.
- Identify the technology; its new ability; what it showed (confirmed, changed or overturned ideas); its limitations; a judgement with reasons and a comparison.