Active SETI

https://en.wikipedia.org/wiki/Active_SETI

"Active SETI is the attempt to send messages to intelligent extraterrestrial life. Active SETI messages are usually sent in the form of radio signals."

"Projects have targeted stars between 17 and 69 light-years from the Earth. The exception is the Arecibo message, which targeted globular cluster M13, approximately 24,000 light-years away.

"The first message to reach its destination will be RuBisCo Stars, which should reach Teegarden's star, a brown dwarf in 2021."

What would you tell aliens about humankind?

http://www.astronomy.com/news/2018/11/new-arecibo-message

"In 1974, the Arecibo Observatory beamed a message from humanity out toward the stars. But that message no longer reflects us so it's time to make a new one."

"The Arecibo Observatory is home to one of the largest, most powerful radio telescopes in the world. Spanning 1,000 feet (305 meters) in diameter, the huge telescope was used in 1974 for a unique purpose: to transmit a message from humanity to the stars. But while that message has not yet reached its destination — the globular cluster M13, roughly 21,000 light-years away time has marched forward, and so has society. A message sent in 1974 no longer truly reflects us, which is why researchers at the observatory are developing the New Arecibo Message."

Wikipedia: Arecibo Message

Updated April 17, 2020

My comment: If I was on the other side of the galaxy and received the Arecibo message (see below) I might be able to identify the person as the sending ET. The purple shape looks like another two-armed species. It does not look like a radio telescope as intended because it faces downward not to the sky. The DNA structure looks like a wave signal not DNA because the man symbol doesn't have a woman alongside him to give meaning to the function of DNA.

"Dr. Frank Drake, then at Cornell University and creator of the Drake equation, wrote the message with help from Carl Sagan, among others. The message consists of seven parts that encode the following (from the top down)."

The numbers one (1) to ten (10).
The atomic numbers of the elements hydrogen, carbon, nitrogen, oxygen, and phosphorus, which make up deoxyribonucleic acid (DNA).
The formulas for the sugars and bases in the nucleotides of DNA.
The number of nucleotides in DNA, and a graphic of the double helix structure of DNA.
A graphic figure of a human, the dimension (physical height) of an average man, and the human population of Earth.
A graphic of the Solar System indicating which of the planets the message is coming from.
A graphic of the Arecibo radio telescope and the dimension (the physical diameter) of the transmitting antenna dish."

[Arecibo SETI message image credit in astronomy.com: Arne Nordmann (norro)]

We Should Message Extraterrestrial Civilizations, Not Just Listen for Them, in Scientific American, by Jerome H. Barkow, March 29, 2020

This Scientific American post is in favor of contacting ETs.

"The major impact of interstellar communication may be not so much what is communicated but simply the evidence that they are there."

Is Starlink Active SETI?

SpaceX plans to launch into orbit 10's of thousands of satellites to provide inexpensive, global internet services.

A side-effect or perhaps intentional result of Starlink is to create a powerful beacon of radio waves alerting ETs scouring the skies that Earth has intelligent life.

ETs monitoring the Starlink signals may conclude the Starlink satellites were launched by a rogue faction that saw no need to provide internet services without polluting Earth's night skies and leaking radio waves to ETs.

References

Astronomy Group Says Starlink and Other Satellite Constellations Could Threaten Science, by Space.com, June 4, 2019

Here's what you need to know about SpaceX's Starlink internet service, CNN, October 26, 2019

This Is How Elon Musk Can Fix The Damage His Starlink Satellites Are Causing To Astronomy, Forbes, Nov 20, 2019

SpaceX’s cheap internet could cost us the night sky, by Popular Science, November 13, 2019

Will Elon Musk’s Starlink satellites harm astronomy? Here’s what we know, National Geographic, May 29, 2019