Stephen W Hurrell

Stephen W. Hurrell
Born	1956 (age 69–70)
Residence	Ellesmere Port, Cheshire, United Kingdom
Nationality	English
Known for	Reduced Gravity Earth, Expanding Earth, Gravity, Structual Dynamics of Dinosaurs
Scientific career
Fields	Engineering Designer, Palaeogravity, Expanding Earth

Stephen W. Hurrell (born 1956) is an English mechanical engineering designer and science author best known for the Reduced Gravity Earth theory — the proposal that the Earth's surface gravity was substantially lower in the distant past, and that this, rather than any special biological adaptation, is what allowed dinosaurs, giant insects and giant plants to grow to sizes unmatched by any land life today. He argues that this reduced palaeogravity is direct biological evidence for an Expanding Earth, a position outside mainstream geophysics but developed over three decades of published work.

Biography

Stephen Hurrell was born in 1956 in Great Britain and lives in Ellesmere Port, Cheshire. He worked in a succession of mechanical engineering design posts for various companies, and it was his work as a mechanical design engineer at the UK's Electricity Research Centre — where he was concerned with scaled engineering structures — that gave him his original insight. Designing and testing scale models made him familiar with the way that structural scale effects work: strength scales with cross-sectional area (the square of linear size) while weight scales with volume (the cube of linear size), so a structure cannot simply be enlarged without becoming relatively weaker. Applying that same reasoning to dinosaurs as engineering structures led him to conclude that the largest of them could not have been supported by their own skeletons under present-day gravity.

He is a named inventor on several British patents from his engineering career, including "Three dimensional optical memory" (GB2205173, 1991), "A device for minimising liquid surging during pouring" (GB2337246, 1999) and "Carton with air pipe" (GB2345688, 2000). He is now retired from engineering design and writes on palaeogravity and Earth expansion, maintaining the website dinox.org. He is married with a son.

Scientific contributions

The Reduced Gravity Earth theory

Hurrell's central claim is that, for a given form of life, the linear scale of land-based life is inversely proportional to the strength of gravity. Modern land animals are built to the limits of what present-day gravity permits; the giants of the fossil record are not. Sauropods such as Giraffatitan (Brachiosaurus) brancai, large theropods such as Tyrannosaurus rex, pterosaurs such as Quetzalcoatlus northropi, dragonflies with wingspans far beyond any living insect, and giant arthropods such as the eurypterid Hibbertopterus and the land scorpion Pulmonoscorpius kirktonensis all appear, on straightforward engineering analysis, to have bones, muscles, ligaments and wings too weak for their estimated masses if the gravity they lived in was the same as ours.

Rather than treat this as a puzzle requiring special pleading about dinosaur physiology, Hurrell takes the mechanical shortfall at face value and asks what surface gravity would make these animals mechanically ordinary. His analyses indicate that ancient gravity would need to be roughly half its present value to explain the largest dinosaurs, and that palaeogravity has increased slowly and steadily towards the present-day figure.

Methods of calculating palaeogravity

A distinctive feature of Hurrell's work is that he treats palaeogravity as a measurable quantity rather than an assumption. He has developed and published several independent methods of estimating it, including:

• Dynamic similarity — comparing gait and stride patterns inferred from trackways with the dimensionless relationships that govern walking and running.
• Leg bone strength — comparing the cross-sectional strength of fossil limb bones with the weight they would have had to carry.
• Ligament and tendon strength — applying known biological material limits to reconstructed skeletons.
• Blood pressure — the circulatory head required to pump blood to the raised skull of a long-necked sauropod.
• Fossil feathers — a method he introduced in 2014, using the aerodynamic and structural properties of preserved feathers to constrain the gravity in which the animal flew.

He has applied these techniques to a long series of individual specimens — among them Tyrannosaurus rex, Acrocanthosaurus atokensis, Coelophysis bauri, Gigantoraptor erlianensis, Ankylosaurus magniventris, Euoplocephalus tutus, Megalosaurus bucklandii, the giant rhinoceros Paraceratherium transouralicum and the iguanodont Mantellisaurus atherfieldensis — each yielding a separate palaeogravity estimate. The consistency of the results across different animals, different geological ages and different calculation methods is, in his view, the strongest argument that a real physical effect is being measured.

Implications for the Expanding Earth

Hurrell's palaeogravity results connect his work to Expansion Tectonics. Geologists working from entirely independent evidence — continental fit, sea-floor spreading data and palaeomagnetic radius determinations — had already concluded that the ancient Earth was smaller in diameter. Hurrell notes that his biologically derived gravity values imply an ancient Earth of comparable dimensions, so that two wholly separate lines of reasoning converge on the same picture.

Comparing his results against the competing versions of Earth expansion, he finds that a constant mass expansion (in which the Earth simply swells at fixed mass, which would raise rather than lower ancient surface gravity) does not fit the fossil evidence, whereas an Increasing Mass Expanding Earth model does: if the Earth has gained mass over geological time, surface gravity rises steadily as the planet grows, which is exactly the pattern his palaeogravity calculations show. This aligns his work closely with that of James Maxlow, whose geological reconstructions of a smaller ancient Earth Hurrell reviewed in 2015, and places him in the tradition of Samuel Warren Carey, who added a section on dinosaurs to Earth Universe Cosmos after reading Hurrell's work.

Historical scholarship

Alongside his technical papers, Hurrell has worked to recover the history of the expansion idea and of scientific dissent generally. He edited the 2020 volume The Hidden History of Earth Expansion: Told by researchers creating a Modern Theory of the Earth, contributing both a long opening essay, "The Science Innovators: an historical context", and a personal chapter, "From dinosaurs to Earth expansion". He has also published research recovering the forgotten nineteenth-century expansion speculations of Alfred Wilks Drayson (1827–1901) and William Thorp (1804–1860).

CNPS talks

He has appeared in the CNPS online seminar and livestream series:

• "Live Presentation: Palaeogravity - Calculating Ancient Gravity using Dinosaur Fossils" (18 July 2020)
• "New Earth Expansion Book: Live Interview with author Stephen Hurrell" (11 July 2020)

Books

• 2020 - The Hidden History of Earth Expansion: Told by researchers creating a Modern Theory of the Earth (editor), Oneoff Publishing.com, ISBN 9780952260387 (Publisher details)
• 2011 - "Dinosaurs and the Expanding Earth - Third edition", Oneoff Publishing.com, ISBN 9780952260370 (Read in full)
• 2003 - "Dinosaurs and the Expanding Earth - Second edition (ebook)", ISBN 095226031X (Publisher details)
• 1994 - Reprinted 1996 & 2001 - "Dinosaurs and the Expanding Earth - First edition", One Explanation for the Gigantic Sizes of Some Pre-historic Life, Oneoff Publishing, ISBN 0952260301

Selected papers

• 2025 - "A palaeogravity calculation based on Mantellisaurus atherfieldensis"
• 2022 - "Size limits on dragonflies"
• 2022 - "A palaeogravity calculation for the ancient land scorpion Pulmonoscorpius kirktonensis"
• 2021 - "A palaeogravity calculation for the gigantic fossil arthropod Hibbertopterus (Eurypterida)"
• 2020 - "The flying ability of the pterosaur Quetzalcoatlus northropi in a reduced gravity" (also presented as a poster at the Palaeontological Association Annual Meeting, December 2020)
• 2020 - "Can we calculate Palaeogravity?"
• 2020 - "From dinosaurs to Earth expansion", in The Hidden History of Earth Expansion, pp. 263-284 (pdf)
• 2020 - "The Science Innovators: an historical context", in The Hidden History of Earth Expansion, pp. 11-86
• 2019 - Palaeogravity calculations based on weight and mass estimates of Paraceratherium transouralicum, Megalosaurus bucklandii (pdf), Euoplocephalus tutus (pdf), Ankylosaurus magniventris, Gigantoraptor erlianensis, Coelophysis bauri (pdf), Acrocanthosaurus atokensis (pdf) and four Tyrannosaurus rex specimens
• 2018 - "A palaeogravity calculation based on weight and mass estimates of Giraffatitan (=Brachiosaurus) brancai"
• 2017 - "Early speculations about Earth expansion by Alfred Wilks Drayson (1827-1901) and William Thorp (1804-1860)" (pdf)
• 2015 - "Book Review of James Maxlow's On the Origin of Continents and Oceans: A Paradigm Shift in Understanding" (pdf)
• 2014 - "A New Method to Calculate Palaeogravity Using Fossil Feathers", NCGT Journal, v. 2, no. 3, September 2014, pp. 29-34 (pdf)
• 2012 - "Ancient Life's Gravity and its Implications for the Expanding Earth", in The Earth Expansion Evidence - A Challenge for Geology, Geophysics and Astronomy (37th International School of Geophysics workshop, Erice, Sicily, 2011) (pdf)
• 1997 - "Dinosaurs and gravity: revolutionary theory on why dinosaurs were so huge", EPE-Chertsey, 79, p. 95

Patents

• 2000 - "Carton with air pipe", GB2345688
• 1999 - "A device for minimising liquid surging during pouring", GB2337246
• 1991 - "Three dimensional optical memory", GB2205173

External links

• dinox.org - Hurrell's website on reduced palaeogravity and Earth expansion
• Publications by Stephen W. Hurrell
• The Reduced Gravity Earth theory
• Dinosaurs in a reduced gravity
• Oneoff Publishing.com
• ResearchGate profile