This article comes from the WeChat official account: Made (ID: xingshu100) , the picture from: Visual China

On the evening of November 18, 2019, Northwestern University (Northwestern University) astronomer Cliff Johnson (Cliff Johnson) using a telescope to measure two very dim dwarf galaxies (Magellan Cloud) , suddenly found a large group of strange objects across the sky, and traces left in the camera.

A large group of strange objects cross the sky

One or two satellites that occasionally enter the field of view will not destroy the observations, but it will take great efforts to delete the traces they left in the camera. 19 satellites were found at once, this is notIt has never happened before, and it has caused 15% to 20% of the monitoring images to be completely lost.

What the hell is going on?

Everyone may have heard of SpaceX’s “Star Chain Project” (Starlink) . Musk’s vision for Starchain is that this is a low-orbit communication satellite constellation plan, using 6G networks and space data as carriers to create the next generation of satellite networks and lead the earth into the era of space-based Internet.

On November 11, 2019, the SpaceXFalcon 9 rocket was successfully launched from Cape Canaveral Air Force Base and carried 60 Starlink satellites < br>

The total number of satellites in the “Star Chain Project” may reach 42,000. The more than 40,000 satellites are distributed on a series of orbital surfaces with different altitudes and different inclination angles from 330 kilometers to 1300 kilometers. The satellite adopts a low-cost modular design, with a single weight of about 230 kg. It is launched using the Falcon Nine rocket, with 60 launches each time. At present, 420 launches have been launched.

In addition to SpaceX, Amazon and OneWeb in the United States are also promoting similar projects.

Astronomers are bothered

The StarChain project, which aims to meet the needs of all human beings on the Internet at any time and anywhere, is so powerful that everyone should love it, right? Unfortunately, astronomers don’t think so.

In order to obtain a pure starry sky, astronomers had to build telescopes to the inaccessible Chilean Amasones Mountain, XiaweiYimonakia and other places even have to sue for repairing telescopes and indigenous peoples. But Musk’s star chain plan may destroy the last unpolluted sky.

On the one hand, more and more satellites will greatly increase the possibility of satellites crossing the telescope. On the other hand, a bright satellite will cause the observation results to be blurred, causing “pollution” that is extremely difficult to eliminate for astronomical observations.

Examples of astronomical observations published by the International Astronomical Union. The highlight in the picture is the astronomical object that the Lowell Observatory in the United States is trying to observe. The bright line in the picture is the trace left after the star chain satellite invades the field of view of the telescope (Image source: International Astronomical Union)

To ensure that the Internet reaches a certain speed, these small new satellites are very close to the Earth ’s orbit, but this intimate contact makes them brighter in the sky. Patrick Seitzer, an astronomer at the University of Michigan who studies orbital debris, (Patrick Seitzer) said: “Astronomical telescopes usually require long exposures to capture distant galaxies. Weak signals, and the satellites launched by these companies represented by SpaceX, are brighter than 99% of all kinds of objects currently in Earth orbit. “

Physicist Tony Tyson (Tony Tyson) is the chief scientist of the Chilean Vera Rubin Observatory Large Weather Observation Telescope. The telescope is currently under construction. When it is finally completed, it will be able to capture a sky area 40 times the size of the full moon and find objects that are 10 million times weaker than the naked eye can see.

From 2023, the US $ 500 million construction of the observatory will enter the entire night skyA 10-year survey (This project is called “Space-time Heritage Survey” or “LSST”) , it will observe and study dark matter, dark energy, etc. Phenomena, and searching for small objects that pose a potential collision threat to the Earth. It can be said that this is an astronomical device that can not only reveal the new basic laws of the material world for human beings, but also provide protection for the catastrophe that all humanity may face in the future.

The Vera Rubin Observatory is under construction at LSST (Photo credit:

If its observations are disturbed by Starchain or other satellites, it is not just the institutions behind this telescope and the scientists who conduct related research, but also many survey observation projects around the world. For example, the Sloan Digital Sky Survey in the United States and the LAMOST Sky Survey Telescope in China.

There are too many satellites, and the telescope observations are full of foggy stripes

SpaceX said they have been working with scientists in the astronomy community, especially the Vera Rubin Observatory, to alleviate this conflict. In an experiment, SpaceX customized a dark coating for the bottom surface of one of the satellites during launch to see whether it was obvious in the telescope observation.