APOD - The Galactic Plane: Radio Versus Visible

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2025 November 18

The Galactic Plane: Radio Versus Visible
Image Credit: Radio: S. Mantovanini & the GLEAM team; Visible: Axel Mellinger (milkywaysky.com)

Explanation: What does the Milky Way look like in radio waves? To better find out, GLEAM surveyed the central band of our galaxy in high resolution radio light as imaged by the Murchison Widefield Array in Australia. As the featured video slowly scrolls, radio light (71 - 231 MHz) is seen on the left and visible light -- from the same field -- on the right. Differences are so great because most objects glow differently in radio and visible light, and because visible light is stopped by nearby interstellar dust. These differences are particularly apparent in the direction toward the center of our galaxy, seen about a third of the way through. Among the many features that appear in the radio, bright red patches are usually supernova remnants of exploded stars, while areas colored blue are stellar nurseries filled with bright young stars.

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Tomorrow's picture: the big V

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Amber Straughn Specific rights apply.
NASA Web Privacy, Accessibility, Notices;
A service of: ASD at NASA / GSFC,
NASA Science Activation
& Michigan Tech. U.

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APOD - Comet Lemmon's Wandering Tail

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2025 November 17

Comet Lemmon's Wandering Tail
Image Credit: Ignacio Fernández

Explanation: What has happened to Comet Lemmon's tail? The answer is blowing in the wind — the wind from the Sun in this case. This continuous outflow of charged particles from the Sun has been quite variable of late, as the Sun emits bursts of energy, CMEs, that push out and deflect charged particles emitted by the comet itself. The result is a blue hued ion tail for Comet C/2025 A6 (Lemmon) that is not only impressively intricate but takes some unusual turns. This long-duration composite image taken from Alfacar, Spain last month captured this inner Solar System ionic tumult. Comet Lemmon is now fading as it heads out away from the Earth and Sun and back into the outer Solar System.

Tomorrow's picture: radio milky way

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< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Amber Straughn Specific rights apply.
NASA Web Privacy, Accessibility, Notices;
A service of: ASD at NASA / GSFC,
NASA Science Activation
& Michigan Tech. U.

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This is an automated email. If you notice any problems, just send me a note at gtracy@gmail.com. You can add and remove email addresses to this distribution list here, https://apodemail.org.Unsubscribe