Stars, planets or satellites? How to know what you see in the sky

There are many light objects in the night sky. But how do you know if you’re looking at a star, a planet, a satellite or something else entirely?

Munich – When the temperature is mild in spring and summer, people like to spend a lot of time outside and look at the starry sky at night. There are many objects that are very bright and visible especially if you don’t look at the sky often. Whether it’s a bright, stationary light, a fast-moving “star” in the sky, or something else that catches your attention, most celestial observations are easy to identify.

The most important information to know what you saw in the sky is the direction and time of observation. If you don’t have a compass handy, you can use the sun to roughly determine your direction. For example, use the well-known saying “The sun rises in the east and rises high in the south.” It will land in the west, but it will never appear in the north.†You can tell some things more easily by just looking at the direction. In the spring of 2023, for example, the planet Venus will be visible in the west during the evening. So if you see a very bright “star” in the west in the evening, it is most likely the “evening star” of Venus.

A bright light in the sky does not move: stars or planets

If you see a “bright light” in the sky that does not move for a long time, it is most likely a star or a planet. To tell them apart, take a closer look: The stars twinkle, the planets don’t. The twinkling of stars is caused by the earth’s turbulent atmosphere, through which light must pass to reach human eyes. Although light from the planets also penetrates the Earth’s atmosphere, the glow is usually invisible because the planets are brighter.

If you’re still not sure whether you’ve seen a star or a planet, there are other possibilities. For example, use a digital star map like the free Stellarium app (also available for smartphones) to find out what you’ve discovered in the sky. After installing the app, you can point your smartphone at a celestial body to find out what it is. To distinguish the stars from the planets, it also helps to observe the celestial body for several nights. Planets move through the starry sky over time, moving from one constellation to another. That is why they were called “moving stars”.

A “bright light†moves quickly in the night sky: a satellite or an airplane

If you see a “bright light” moving quickly across the night sky, there are several possibilities as to what you may have seen. For example, it can be a satellite or an airplane. The difference is simple: the plane flashing, the satellite is not. If something in the sky is glowing or has green or red lights, it is a bird. You can recognize satellites by the fact that they do not blink, but move through the sky as much light or less light and suddenly disappear again.

With some experience you can distinguish between different types of satellites. For example, SpaceX’s “Starlink” satellites usually appear in large groups – one satellite is followed by several others. The International Space Station ISS, which can often be seen in the night sky, remains alone and brighter than the “Starlink” satellites. You can monitor the movements of various satellites using programs such as “Stellarium” or “Sky Above”. To do this, you need not only the direction of the survey but also the exact time that you did your survey.

Odd opinion: “Starlink” satellites cause confusion in space

In addition to these everyday aerial observations, there are also more unusual sightings where people even call UFO reporting stations. The UFO reporting center of the Central Network for the Study of Atmospheric Phenomena (CENAP) provides information about these phenomena, and balloons or drones are often behind the observations. However, the “Starlink” satellites often confuse skygazers.

That’s not surprising: they can’t just be seen as individual satellites flying one behind the other in the distance. Shortly after takeoff, they come very close to each other, creating an almost ghostly path in the sky. After the launch, many observers describe the “Starlink” satellites as a “string of lights” in the sky.

Rocket launches can also look amazing in the sky

The different phases of a rocket launch can also look strange in space. For example, a spiral can occur when a rocket stage releases its remaining fuel. Occasionally you can also see parts of the rocket burning or the separation of the rocket stage in the sky. However, shooting stars, meteors and fireballs are of natural origin. Here, a larger or smaller rock from space penetrates the earth’s atmosphere and burns up. Information about other fireball sightings can be found in a special database where you can also report your own sightings.

Automated support was used for this article written by the editorial team. The article was carefully checked by editor Tanja Banner before publication.