Stanford
Love Data Week

AI & Astronomy Imagery

AI & Astronomy Imagery Exhibit

In this online exhibit you’ll be presented with an original photo from the Astronomy Picture of the Day (APOD) archive along with its original scientific explanation written by APOD organizers Dr. Robert Nemiroff and Dr. Jerry Bonnell. Following this, we present how AI interprets this scientific content. To generate the AI description, we uploaded the photo without any context (no title, no relevant file name) to ChatGPT 40-mini in Stanford's AI Playground.  Next, we used a generative AI program called Invoke to create a series of images based solely on the original APOD explanation using four different models from HuggingFace (Juggernaut XL V9, OpenJourney v4, SD PhotoReal Photo V2, and Stable Diffusion v1.4).

We ask you to compare the original explanation with the AI generated description, paying attention to the details, or lack thereof, provided in each.  Then to compare the original photo with the AI generated images.  It’s interesting to see what the AI image generator extrapolates from the explanation, how it focuses on some details, but often it seems to miss the core scientific features of the original image.

This page will be updated to display a new astronomical photo each day of Love Data Week 2025, and a full archive of our explorations can be found in the side menu.

Comet ATLAS Rounds the Sun

Astronomy Picture of the Day: January 20, 2025

See APOD explanation.
Comet ATLAS Rounds the Sun

Image Credit: NASA, SOHO Spacecraft, LASCO C3; Processing: Rolando Ligustri

APOD Explanation: Why does Comet ATLAS have such colorful tails? Last week Comet C/2024 G3 (ATLAS) passed its closest to the Sun -- well inside the orbit of Mercury -- and brightened dramatically. Unfortunately, the comet was then so angularly near the Sun that it was very hard for humans to see. But NASA's SOHO spacecraft saw it. Pictured is a SOHO (LASCO C3) image of Comet ATLAS that is a composite of several different color filters. Of the several tails visible, the central white tails are likely made of dust and just reflecting back sunlight. The red, blue, and green tails are likely ion tails with their colors dominated by light emitted by specific gases that were ejected from the comet and energized by the Sun. Currently, Comet ATLAS is showing long tails in southern skies but fading as it moves out of the inner Solar System.

AI Interpretations

AI Generated Description

The image shows a cosmic scene featuring a bright object resembling a comet located in the upper left region. This object has a distinct, colorful tail that radiates outward, displaying hues of blue, green, and white, creating a visually striking effect. Below the comet, there is a large dark circular area that appears to be an occulting disk, which is typically used in solar observations to block the direct light from the Sun or other bright celestial bodies. This disk allows for clearer observation of faint celestial phenomena surrounding it. The background is filled with numerous small white dots, which can be identified as stars or possibly cosmic dust and particles. The overall image provides a snapshot of a dynamic and vibrant space scene showcasing the interaction of a comet with its surroundings.

AI Generated Images

A vibrant, colorful comet appears against a dark cosmic background. The comet has a bright blue-green nucleus and a long tail that gradually transitions from green to orange, creating a dynamic visual effect. Scattered small stars are visible throughout the image, enhancing the sense of depth and vastness in space.
AI Generated with Juggernaut XL V9
An expansive cosmic scene filled with colorful celestial bodies. A prominent, glowing dust trail crosses the top left side of the image, in shades of blue and yellow. Surrounding it are various glowing orbs in shades of blue, green, red, and orange, which represent stars or nebulae. The backdrop features a starry sky with twinkling stars adding depth to the composition.
AI Generated with OpenJourney v4
A dusty trail streaks across the top left corner, near a brown orb that appears to be a planet. A pair of dust trails stream out diagonally from what appears to be a glowing star. Another large glowing star is visible to the right. The background is dark, with faint clouds of dark blue, green, and red, and stars speckled throughout.
AI Generated with OpenJourney v4
A striking celestial arrangement features something that resembles a large glowing nebula, surrounded by multiple bright stars. The edges of the nebula are illuminated, creating a glowing aura. Two bright blue stars are positioned within the nebula-like feature, while two bright yellow stars seem to connect the central nebula to a secondary one at the bottom. The background is filled with distant stars, enhancing the richness of the cosmic vista.
AI Generated with SD PhotoReal Photo V2
A thick dusty trail that looks like clouds billowing after a jetplane streak off to the left from a large bright star-like object. A secondary dusty path, much smoother, looking to be made of very fine dust particles also expands out from the left and lower side of the bright star. A second bright star is in the lower right, with a thin blue tail streaking off to the upper right.
AI Generated with SD PhotoReal Photo V2
A monochromatic cosmic scene showcasing a long, thin cloud resembling the tail of a comet or a nebula traversing diagonally across the image. Three bright, glowing objects flank the cloud, possibly stars or distant celestial bodies. The surrounding space is dotted with faint stars, adding to the overall vastness and mystery of the universe.
AI Generated with Stable Diffusion v1.4

Discussion

Because of SOHO’s unique instrumentation, it was able to capture this photograph of Comet ATLAS passing close by the sun. ChatGPT was able to correctly identify the scene, noting that the device used to take this photograph must have had an occulting disk to block the light from the sun.  Though the description focuses more on the dynamic vibrancy of the image, it also indicates that perhaps SOHO data and imagery was well represented in its training set.

By contrast, the models used in the generative AI platform Invoke clearly have not seen many photos of comets, nor of SOHO’s occulting disk. The SD PhotoReal model interprets the description of this disk as a glowing nebula, while the other two models completely ignore it.  The other SD PhotoReal image in the gallery seems to take inspiration from the contrails of jet planes when depicting a comet’s tail.  Juggernaut focuses on the description of a colorful tail, but ignores the mention of blue and red in the comet.  OpenJourney seems really lost with how to understand the color descriptions, creating blue, green, and red colorful orbs hanging throughout the scene.