Scale Explorer version 2: additional imagery and measurement sources

Image processing: display-resolution derivatives of credited originals. Crops preserve physical objects; feathered edges blend telescope fields into the scene. Infrared observations use assigned visible colours, not natural colour. No image implies endorsement by NASA, ESA, CSA or their partners.

Mercury
assets/v2/mercury.jpg
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Source: https://science.nasa.gov/mercury/
Measured dimension: Mean diameter; 4879400 m
Description: The smallest planet, photographed by MESSENGER. Its heavily cratered surface preserves billions of years of impacts.

Neptune
assets/v2/neptune.jpg
Credit: NASA/JPL
Source: https://science.nasa.gov/neptune/
Measured dimension: Mean diameter; 49244000 m
Description: Voyager 2 photographed this ice giant in 1989. This familiar image has enhanced colour; Neptune looks paler in carefully reconstructed natural colour.

Saturn
assets/v2/saturn.jpg
Credit: NASA/JPL-Caltech/Space Science Institute
Source: https://science.nasa.gov/saturn/
Measured dimension: Equatorial globe diameter; 120536000 m
Description: Cassini photographed Saturn and its rings. The stated diameter measures the equator of the planet itself; the rings extend much farther.

Ceres
assets/v2/ceres.jpg
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Source: https://science.nasa.gov/dwarf-planets/ceres/
Measured dimension: Mean diameter; 939400 m
Description: The largest object in the main asteroid belt is a dwarf planet. This Dawn observation shows its cratered, partly illuminated surface.

Pluto
assets/v2/pluto.jpg
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Source: https://science.nasa.gov/resource/pluto-in-true-color/
Measured dimension: Mean diameter; 2376600 m
Description: New Horizons photographed this icy dwarf planet in 2015. The bright heart includes a vast nitrogen-ice plain.

Europa
assets/v2/europa.jpg
Credit: NASA/JPL-Caltech/SETI Institute
Source: https://science.nasa.gov/photojournal/europas-stunning-surface-2/
Measured dimension: Mean diameter; 3121600 m
Description: Galileo’s global mosaic of Jupiter’s icy moon shows the illuminated part of its globe. Cracks cross its ice shell above a subsurface ocean.

Titan
assets/v2/titan.jpg
Credit: NASA/JPL/Space Science Institute
Source: https://science.nasa.gov/resource/cassinis-view-of-titan-natural-color-composite/
Measured dimension: Mean solid-body diameter; 5149400 m
Description: Cassini’s natural-colour view shows a hazy atmosphere concealing Saturn’s largest moon. The stated diameter is the solid body; the atmospheric haze extends above it.

Southern Ring Nebula
assets/v2/southern-ring.jpg
Credit: NASA, ESA, CSA, STScI
Source: https://science.nasa.gov/asset/webb/southern-ring-nebula-nircam-image/
Measured dimension: Approximate image-field width; 13244980000000000 m
Description: A dying star sheds an expanding shell of gas, seen here by Webb’s NIRCam. The stated size is the image field, not a sharply bounded object. Webb infrared wavelengths are mapped to visible colours.

Ring Nebula
assets/v2/ring.jpg
Credit: ESA/Webb, NASA, CSA, M. Barlow (UCL), N. Cox (ACRI-ST), R. Wesson (Cardiff University)
Source: https://science.nasa.gov/asset/webb/ring-nebula-nircam-image/
Measured dimension: Approximate image-field width; 13528801000000000 m
Description: Webb resolves clumps and filaments in this planetary nebula. Field width is derived from 2.14 arcminutes at approximately 2300 light-years. The stated size is the image field, not a sharply bounded object. Webb infrared wavelengths are mapped to visible colours.

Pillars of Creation
assets/v2/pillars.jpg
Credit: NASA, ESA, CSA, STScI; Joseph DePasquale, Anton Koekemoer, Alyssa Pagan
Source: https://science.nasa.gov/asset/webb/pillars-of-creation-nircam-image/
Measured dimension: Approximate image-field width; 75685600000000000 m
Description: Newborn stars emerge from dusty columns in the Eagle Nebula. The tallest pillar is roughly 4–5 light-years long. The stated size is the image field, not a sharply bounded object. Webb infrared wavelengths are mapped to visible colours.

Cassiopeia A
assets/v2/casa.jpg
Credit: NASA, ESA, CSA, Danny Milisavljevic (Purdue), Tea Temim (Princeton), Ilse De Looze (UGhent); Joseph DePasquale (STScI)
Source: https://science.nasa.gov/asset/webb/cassiopeia-a-miri-image/
Measured dimension: Approximate image-field width; 94607000000000000 m
Description: Webb’s MIRI reveals warm dust and tangled ejecta in the remains of an exploded star. The stated size is the image field, not a sharply bounded object. Webb infrared wavelengths are mapped to visible colours.

Cosmic Cliffs
assets/v2/cliffs.jpg
Credit: NASA, ESA, CSA, STScI
Source: https://science.nasa.gov/asset/webb/cosmic-cliffs-in-the-carina-nebula-nircam-image/
Measured dimension: Approximate image-field width; 151371200000000000 m
Description: The edge of a star-forming region in NGC 3324, sculpted by radiation and winds from young stars. The stated size is the image field, not a sharply bounded object. Webb infrared wavelengths are mapped to visible colours.

Stellar illustrations
Original deterministic procedural surface illustrations, not telescope photographs.
O5V, B0V, A0V, F0V, K5V, M5V, L5V, T5V and Y0V representative radius / effective temperature: Pecaut & Mamajek (2013), updated Mamajek dwarf sequence, https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt
Red giant (25 solar radii), blue supergiant (80 solar radii), Wolf–Rayet (5 solar radii) and neutron star (24 km diameter) are explicitly illustrative class examples, not measured named objects. Stellar classes overlap in size. Wolf–Rayet radii depend strongly on the model and optical-depth boundary.
Background on stellar categories: https://science.nasa.gov/universe/stars/types/
Brown-dwarf colours illustrate atmospheric/infrared appearance; these cool objects are faint at visible wavelengths.

Cassiopeia A field calibration
NASA’s MIRI compass image explicitly states “The field of view shown in this image is approximately 10 light-years across.” This is the basis for the 10 light-year image width, rather than assigning the remnant diameter to the image frame.
https://science.nasa.gov/asset/webb/cassiopeia-a-miri-compass-image/

Dark-matter density simulations
Authors: Philip Mansfield and Benedikt Diemer (Mansfield & Diemer).
Source and usage statement: https://www.benediktdiemer.com/visualization/images/
The authors permit use of the images in publications or presentations with acknowledgement.
The images visualize simulated dark-matter density using the tetrahedral reconstruction method associated with Kaehler and colleagues, not visible-light observations or a measured map of our local Universe.
assets/v2/dark-halo.jpg: L0063 halo 168021665, field width 15 Mpc/h, projection depth 6 Mpc/h.
assets/v2/dark-streams.jpg: L0125 field width 125 Mpc/h, projection depth 12.5 Mpc/h.
assets/v2/dark-web.jpg: L2000 field width 2000 Mpc/h, projection depth 160 Mpc/h.
The simulations use h=0.7; physical field widths at redshift zero are converted by dividing Mpc/h values by 0.7. The differently sized fields are separate simulation views, not nested observations of one place.