Investigate limitations of current scientific instrumentation and how these have constrained scientific inquiry, with reference to a specific field such as genetics or astronomy

What this dot point is asking

NESA wants you to identify how current scientific instrumentation limits the questions that can be asked, with named examples from specific fields. This dot point is about the mutual shaping of science and technology: technology limits science, and scientific breakthroughs open new technologies.

The answer

Every scientific instrument has limits: resolution, sensitivity, cost, accessibility, throughput. These limits shape which scientific questions can be asked and answered.

Categories of limitation

Resolution

The smallest detail an instrument can detect. A light microscope cannot resolve objects smaller than about 200 nm because of the wavelength of visible light. Atoms (about 0.1 nm) and viruses (10 to 100 nm) require electron microscopy.

Sensitivity

The lowest signal an instrument can detect. Detecting a single molecule of a hormone in blood requires extremely sensitive mass spectrometry or radioimmunoassay.

Speed and throughput

How fast measurements can be made. Sanger DNA sequencing (1977) reads 800 base pairs per day. Next-generation sequencing reads billions per day. The same scientific question, the same chemistry, but vastly different throughput.

Cost

Many instruments cost millions to billions of AUD. The Australian Synchrotron cost about 220 million AUD to build. The James Webb Space Telescope cost 10 billion USD. These constraints shape who can use them.

Accessibility

Even when instruments exist, access can be limited. Synchrotron beam time is allocated by peer-reviewed proposal, with success rates of about 30 per cent.

Field example: Genetics

The Human Genome Project (1990 to 2003) was a coordinated international effort to sequence the entire human genome. It cost approximately 3 billion USD and took 13 years.

The limitation. Sanger sequencing reads about 800 base pairs per reaction. Sequencing the 3 billion base-pair human genome required millions of reactions in parallel.

Cost trajectory.

What changed. Next-generation sequencing (Illumina, Pacific Biosciences, Oxford Nanopore) parallelised the sequencing process across millions of microbeads or pores. Australia's Genomics initiative now sequences entire patient genomes routinely as part of clinical care.

What it enabled.

• Personalised medicine.
• Cancer genome characterisation.
• Pre-natal screening (non-invasive prenatal testing).
• Indigenous genome sequencing projects with First Nations consent.
• Pandemic surveillance (COVID-19 variant tracking).

Field example: Astronomy

The limitation

Earth's atmosphere absorbs many wavelengths and blurs ground-based images.

Pre-1990

Ground-based optical telescopes could resolve features about 1 arc-second across, limited by atmospheric turbulence. Infrared astronomy was nearly impossible from the ground because water vapour absorbs infrared.

Solutions

• Space telescopes. Hubble (1990, optical and UV), JWST (2022, infrared), Chandra (1999, X-ray).
• Adaptive optics (1990s onwards). Deformable mirrors that correct atmospheric distortion in real time, reaching near-Hubble resolution from the ground.
• Radio telescopes (less affected by atmosphere). Australia operates the Murchison Widefield Array and the Australian Square Kilometre Array Pathfinder.

What it enabled.

• Discovery of exoplanet atmospheres.
• Hubble's measurement of the age of the universe.
• JWST's imaging of galaxies 13 billion years old.
• The first images of black hole event horizons (Event Horizon Telescope, 2019).

Field example: Microscopy

The limitation. Visible light has wavelengths around 400 to 700 nm. Diffraction prevents resolution of objects smaller than about 200 nm with standard light microscopy.

Solutions.

• Electron microscopy (1930s onwards). Electron wavelengths are about 100,000 times shorter than visible light, allowing resolution to atomic scale.
• Super-resolution microscopy (2000s). STED, PALM and STORM techniques exceed the diffraction limit by clever fluorescence methods. The 2014 Nobel Prize in Chemistry recognised this work.
• Cryo-electron microscopy (cryo-EM). Allows imaging of biological molecules in near-native states without crystallisation.

What it enabled.

• Structure determination of proteins and enzymes.
• COVID-19 spike protein structure (within weeks of the pandemic) using cryo-EM.
• Imaging of viruses and individual molecules.

Cost and access shaping research direction

When instruments are expensive, research direction concentrates around available capabilities.

• Australia's investment in OPAL, the Australian Synchrotron and the Pawsey Supercomputing Centre concentrates research in fields these instruments serve.
• Researchers in fields requiring instruments not available domestically must collaborate internationally or shift their research.
• The Australian Strategic Roadmap for Research Infrastructure (ASRRI) attempts to coordinate national investment.

When a limit is finally lifted

The history of science is full of moments when a technological breakthrough opened entire new fields:

• The microscope opened cell biology and microbiology.
• The telescope opened modern astronomy.
• Mass spectrometry opened modern chemistry and proteomics.
• DNA sequencing opened modern genetics.
• The Hubble Space Telescope opened modern cosmology.

Each breakthrough often follows decades of slow progress in the underlying technology, with the new science enabling the next round of technological advance.

Examples in context

Example 1. Murchison Widefield Array detection limits. The Murchison Widefield Array in WA is a low-frequency radio telescope designed in part to detect the redshifted 21 cm signal from the Epoch of Reionisation, the period roughly 100 to 500 million years after the Big Bang. Despite over a decade of observation and ever-improving foreground subtraction, the EoR signal has not yet been definitively detected. The limitation is not sensitivity alone but the dynamic range required to subtract foreground galactic emission about 10,000 times stronger than the target signal. Each upgrade (MWA Phase II in 2018, Phase III in development) pushes the detection threshold lower but the science target remains just beyond reach. The case illustrates that some questions require multiple generations of instrumentation to answer.

Example 2. Australian BioBank genome cost trajectory. The Australian Genomics Health Alliance's flagship rare-disease genome program could sequence its first whole human genome for around 100,000 AUD in 2010, dropping to about 1,000 AUD by 2020 and projected to fall under 200 AUD by 2027 with Oxford Nanopore long-read technology. The cost drop has not been linear and has periodically stalled as new bottlenecks emerged: read quality, bioinformatics interpretation, ethical handling of incidental findings. The technology constrains both the science (which questions can be asked at population scale) and the ethics (incidental findings of variants of uncertain significance). The case shows that scientific inquiry depends on the cost curve of its enabling technology, not only on the instrument's existence.

Try this

Q1. Explain how the cost of an instrument constrains which scientific questions can be answered. [3 marks]

• Cue. Population-scale questions require cheap measurements; expensive measurements limit sample size and statistical power; mechanism for excluding questions from a research program.

Q2. A team proposes mapping the entire NSW koala genome population to study chlamydia resistance. State two technological limitations they must overcome, and outline one mitigation. [4 marks]

• Cue. Limitations: sample collection in the field, long-read sequencing throughput, computational analysis. Mitigations: targeted sequencing of immune-region genes, partnership with existing biobanks, cloud-based bioinformatics.

Q3. A school astronomy club uses a 200 mm reflector and a CMOS camera to image Jupiter. (a) State one limitation of their instrument. (b) State one secondary data source they could use to supplement their primary images. (c) Outline how data from the James Webb Space Telescope would extend their inquiry. [2+2+2 marks]

• Cue. (a) Atmospheric seeing limits resolution; integration time limited by tracking accuracy. (b) Hubble or JWST archive images; planetary ephemeris from JPL. (c) Infrared wavelengths reveal cloud-deck chemistry impossible to see in visible light.