Astronomy Picture of the Day

space
text analysis
astronomy
How often is the Sun mentioned in the Astronomy Picture of the Day?
Author

Cole Baril

Published

January 20, 2026

Load Packages

require(pacman)
p_load(tidytuesdayR, magick, tidyverse, janitor, here, trashpanda, rnaturalearth, rnaturalearthdata, glue, ggtext, showtext, ggside)

Load Data

tuesdata <- tidytuesdayR::tt_load('2026-01-20')
apod <- tuesdata$apod

Data Cleaning

sun_mentions <- apod |> 
mutate(
  sun_mention =
    str_detect(title, regex("(?<![A-Za-z])sun(?![A-Za-z])", ignore_case = TRUE)) |
    str_detect(explanation, regex("(?<![A-Za-z])sun(?![A-Za-z])", ignore_case = TRUE)))

sun_mentions_cleaned <- sun_mentions |> 
  filter(sun_mention == TRUE)

# Compute % of month with sun mentioned
apod_solar <- sun_mentions |>
  mutate(
    month = month(date, label = TRUE, abbr = TRUE),
    year = year(date)) |>
  group_by(year, month) |>
  summarise(
    sun_share = mean(sun_mention, na.rm = TRUE),
    .groups = "drop")

apod_solar_side_x <- sun_mentions |>
  mutate(
    month = month(date, label = TRUE, abbr = TRUE),
    year = year(date)) |>
  group_by(year) |>
  summarise(
    sun_share = sum(sun_mention, na.rm = TRUE),
    .groups = "drop")

apod_solar_side_y <- sun_mentions |>
  mutate(
    month = month(date, label = TRUE, abbr = TRUE),
    year = year(date)) |>
  group_by(month) |>
  summarise(
    sun_share = sum(sun_mention, na.rm = TRUE),
    .groups = "drop")

Plot

plot <- ggplot(apod_solar, aes(year, fct_rev(month), fill = sun_share)) +
  geom_tile(color = "black", linewidth = 0.15) +
  geom_xsideline(
    data = apod_solar_side_x,
    aes(y = sun_share, x = year),
    inherit.aes = FALSE,
    linewidth = 1,
    colour = "#FDB813",
    alpha = 0.9) +
  geom_ysidecol(
    data = apod_solar_side_y,
    aes(x = sun_share, y = month),
    inherit.aes = FALSE,
    fill = "#E3A93B",
    alpha = 0.9
    ) +
  scale_fill_gradient(
    low = "#0B1026",   
    high = "#FDB813",  
    labels = scales::percent,
    name = "Sun Mentions") +
  labs(
    x = "Year", y = "Month",
    title = "When the Sun Appears in Astronomy Picture of the Day Posts",
    subtitle = "Share of titles and explanations mentioning the Sun by month (2007–2025) \nEach tile = % of that month mentioning the Sun") +
  theme_minimal(base_size = 12) +
  scale_x_continuous(expand = c(0, 0)) +
  scale_xsidey_continuous(breaks = c(100, 120, 140)) +
  scale_ysidex_continuous(breaks = c(0, 100, 200)) +
  theme(
    panel.grid = element_blank(),
    plot.background = element_rect(fill = "#070B1A", color = NA),
    panel.background = element_rect(fill = "#070B1A", color = NA),
    text = element_text(color = "#F4E9D8"),
    axis.text = element_text(color = "#F4E9D8"),
    legend.key = element_rect(fill = "#070B1A"),
    plot.title = element_text(face = "bold"),
    axis.title = element_text(face = "bold", size = 14),
    axis.text.x = element_text(size = 13),
    axis.text.y = element_text(size = 13)
    ) +
  add_caption_cwb(type = "plot", 
           include_data_source = TRUE, 
           data_source = "NASA Astronomy Picture of the Day Archive")


# Save and display images
current_dir <- dirname(knitr::current_input())
plot_name <- "apod_sun_mentions.png"

ggsave(plot = plot, 
       dpi = "screen",
       width = 16,
       height = 12,
       device = ragg::agg_png,
       filename = file.path(current_dir, plot_name))


img <- image_read(file.path(current_dir, plot_name))

img_card <- image_scale(img, "1200x675")           
img_card <- image_extent(
  img_card,
  geometry = "1200x675",
  gravity = "center"
)

# Save as card preview
image_write(img_card, path = file.path(current_dir, "preview.png"))

knitr::include_graphics(
  file.path(current_dir, plot_name)
)

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