When you see a headline that says “Scientists study 100 alien signals” you might think about people who study space trying to hear messages from other worlds. They are like messages that someone from another planet might be sending to Earth. The idea of signals is really interesting because it makes you wonder if we are really alone in the universe or if there are other people out there trying to talk to us.

The headline “Scientists study 100 alien signals” is talking about scientists who are trying to figure out if these signals are really from other planets or not. They have to listen to these signals and try to understand what they mean. It is like trying to solve a puzzle. The scientists are looking at these signals to see if they can find any clues that might tell us something, about other worlds. What is actually happening is. More cautious and in many ways more impressive. Scientists have finished one of the citizen powered Search for Extraterrestrial Intelligence efforts ever run. They have looked at a lot of radio data and found 100 Search for Extraterrestrial Intelligence signals that are interesting. These Search, for Extraterrestrial Intelligence signals are now worth taking a look at with newer and more powerful telescopes.

This moment is really emotional because it reminds me of the Arecibo Observatory. The Arecibo Observatory is a special place in Puerto Rico. It was a deal when the Arecibo Observatory collapsed in 2020. This was the end of a part of history. The Arecibo Observatory was a part of the SETI@home project. The SETI@home project is famous for using computers from peoples homes to look for things, in recordings. Millions of people helped with the SETI@home project by letting it use their home computers when they were not using them. The Arecibo Observatory sent a lot of data to the SETI@home project. The search that has been going on for a time is finally coming to an end. It has finished looking at the information and now we have a lot of new data, new ways of doing things and a list of possible signals that the search found. These signals from the search could help us decide what to look at next when we do observations, with the search. The search is really important. It has given us a lot of useful information.

Here is what happened. We are going to talk about those 100 signals. We will explain what those 100 signals really mean. We will also talk about why thiss hard to do. Then we will discuss what happens with those 100 signals next.

1) The Arecibo telescope was a deal for the people who work at SETI. SETI is the organization that searches for life in space. The Arecibo telescope was really good at helping SETI do its job. It could. Receive messages from very far away. This was important for SETI because they wanted to see if they could find any signs of life there. The Arecibo telescope was a part of this search. SETI used the Arecibo telescope to look for signals from planets. They were hoping to find something that would show them that they are not alone in the universe. The Arecibo telescope was very good, at this kind of work. That is why it mattered much to SETI.

Arecibo was a famous tool that helped people listen to the universe for a very long time. The big area it covered made it very good at picking up signals from far away. This is important for the Search for Extraterrestrial Intelligence or SETI because any signals that come from stars or planets would be very faint by the time they get to Earth. Arecibo was good at detecting these signals like radio emissions from distant objects, which is what SETI is looking for. SETI wants to find out if anyone or anything else in the universe is sending out signals, like radars or other technology that we can detect with tools, like Arecibo.

The Arecibo telescope stopped working in 2020 which meant it could not be used to make observations.. This did not mean that the information it had already collected was useless. The SETI@home project had collected a lot of data from the Arecibo telescope over the years. This Arecibo data was still very useful because it could be looked, at again with better computer programs and powerful computers than were available when the Arecibo data was first recorded.

The telescope is gone,. The voice recordings from the telescope are still here. These are like boxes of tapes that we can listen to again with new audio software. We can use the software to take another look at the voice recordings, from the telescope.

2) What SETI@home actually. Why the SETI@home project was revolutionary. The SETI@home project was a deal. It was a way for people to help search for life outside our planet. The SETI@home project used computers from people around the world to look at signals from space. This was a cool thing, about the SETI@home project. The SETI@home project showed us that we can work together to do things.

The SETI@home project started in 1999. It became really well known as a great example of people helping with science on the internet. People who wanted to help installed a program on their computers. This program downloaded pieces of data from radio telescopes and looked at them when the computer was not being used for anything else. Then it sent the results back, to the computers so they could look at them more closely and see how they ranked.

Citizen computing is a great thing. It has helped people in ways. Citizen computing has made it possible for ordinary people to get involved in things that were previously only done by experts. This is very good, for citizen computing because it allows people to use their skills to help with citizen computing projects. Citizen computing has also helped people to learn things and to work together on citizen computing initiatives. The fact that people can do citizen computing has helped a lot.

Radio astronomy gives us a lot of data. It is hard to find the radio astronomy data that’s interesting because we have to look at many things. We have to look at radio channels and time. We also have to look for radio astronomy signals that change a bit because the Earth is moving and the radio astronomy transmitter is far away. This change in radio astronomy signals is called a Doppler effect, in radio astronomy.

That means you are not looking for one needle in one haystack. You are looking for possible needles and each of these needles could be pointed in many different ways inside a really big field of haystacks. The thing is, the field of haystacks is enormous and the needles are the things you are trying to find. You have possible needles to search for and that makes it even harder.

The SETI@home project found a way to deal with this problem by sharing the work across millions of devices. This project was around for a time and it got a lot of people to help out. People say that more, than 2 million people worked on SETI@home and shared their computer power over the years.

The outcome is that a small research group does not have to depend on one computer system. The project can now do lots of searches over and over again in archives. This means the project can look at the research data in a way using many computers at the same time and search, for things many times. The project can use archives and search them many times, which is what the research group needs to do.

3) The idea of “12 billion signals of interest” sounds really crazy. What exactly does signals of interest mean in this context?

The phrase “signals of interest” in this story is really not understood by a lot of people. When we talk about signals of interest in the data from SETI it does not mean that we found messages from aliens or anything like that. It simply means that the computer program found a lot of things that were worth writing down. There were 12 billion things that the software thought were important enough to log. These things can be anything from a spike in the data to a big burst of energy that does not happen very often. The software is just looking for things that stand out from the noise. The software is looking for signals of interest that’re different, from the usual noise. Signals of interest are things that the computer program thinks are worth looking at.

The radio data is really messy. There are some things that make the radio data seem interesting. These things come from:

Human interference from things like satellites, aircraft and ground transmitters can be a problem. Electronics and even something simple, as microwave ovens can also cause trouble. They can pollute the radio bands. That is not good. Human interference is an issue when it comes to radio bands.

Natural things in space like pulsars and masers and big bursts of energy, from stars can make flashes or small signals. Pulsars and masers and stellar flares and other things that happen in space can create bursts or narrow features.

Instrument effects: quirks of receivers, calibration artifacts, or processing glitches.

Sometimes things happen by chance. It looks like there is a pattern but really it is just random noise. This kind of thing is what people call a fluke. Statistical flukes are when random things happen. They look like they are supposed to happen that way but they are not. Statistical flukes can be confusing because they look like they mean something. They do not. Statistical flukes are random noise.

The first stage is on purpose very broad. It tries to catch all the things that could possibly be out of the ordinary. Then it filters out everything that’s not really strictly. The first stage of this process is like a net that catches everything and then the filtering stage is very tough, on the things that the first stage catches. The first stage is supposed to catch all the things.

The process of filtering is really important because it helps to turn a number of detections into a small list that you can actually look into. This list is small enough that you can realistically investigate the detections, on it. The filtering is what makes this happen. It takes billions of detections. Turns them into a shortlist of the most important ones.

4) The long “winnowing” process: from billions to 100

The people working on the project said that the team worked on this for years. They were trying to make sense of the things they found. The team got rid of the things that were clearly not important. They put together the things that happened over and again. The team did tests to figure out what was just noise around them and what was something real that was coming from away in the sky. They wanted to see if it was something that stayed in the place, in the sky. The team worked on this project for a time to get the detections right.

A common way to describe the narrowing of the blood vessels is that the blood vessels get smaller. The narrowing of the blood vessels can be described in a way. People often say that the narrowing of the blood vessels happens when the blood vessels get narrower. This is what the narrowing of the blood vessels is.

They have found about 12 billion things that’re suspicious, over the years when they were looking at all the information. The company has logged all of these 12 billion detections.

Reduced to around a million candidates through deeper filtering

Reduced again to the top 100 most compelling “worth a second look” signals

What makes a signal worth taking another look at? I think a signal is worth another look when it seems important or interesting. A signal is worth another look when we think it might be useful to understand what it is saying. We should take another look at a signal when we are not sure what it means. Sometimes a signal is worth another look because it can help us learn something about signals.

When I see a signal that’s worth another look I want to know more, about the signal. I think about what the signal’s trying to tell me and I try to understand the signal better. A signal is really worth another look when it can help me make a decision. We should always take another look at a signal when we are not sure if it is real or not.

When we are talking about SETI, the way we score things can be different.. Usually when we are looking at SETI candidate ranking we like to see things like:

Narrowband structure (very thin in frequency).

Many things in nature are really wide ranging. But when we see narrow band emissions that can mean technology from natural sources, like the sun is not the cause it is technology that is doing this because natural sources are broader and technology can produce narrowband emissions.

Doppler drift consistency.

If you have a transmitter that’s really far away from us and it is on a planet that is spinning around and also moving around its star then we can expect to see a change in the frequency of the signal that the transmitter is sending to Earth. This change in frequency is something that we can predict. The transmitter, on the planet is going to look like it is changing frequency to us on Earth.

Sky localization.

Does the signal map to a particular point in the sky rather than “following the telescope” or appearing everywhere?

Repeatability.

A real signal from space like a message from aliens might keep repeating. This signal, from space might not follow a schedule that we can figure out.

RFI-likeness penalties.

If something looks like the kinds of interference patterns that we already know about then it is considered to be less important. The people in charge will take a look, at the interference patterns that we have seen before and they will compare them to this new thing. If it resembles known interference patterns then it is downgraded. This is what happens to things that’re not very unusual or exciting like the known interference patterns that we have dealt with many times before.

With these rules the list is not about the “top 100 aliens”. It is about the ” 100 things that are hardest to dismiss quickly”. The things on this list are the 100 things that are hardest to dismiss quickly, like aliens.

5) Why confirmation is so difficult (and why 100 is a sensible number)

You might wonder, what is going on here. If the people at SETI found something that seems odd why do they not just say they were successful? The reason for this is that SETI has to meet a high standard. If they say they found technology from life that would be one of the biggest discoveries that people have ever made. So the proof that they need to show has to be extremely good. The people at SETI are looking for technology and they have to be very careful. The discovery of technology would be a big deal, for people so SETI has to make sure they are right.

The big enemy: radio interference (RFI)

Our daily life is filled with radio signals around us. Even the special bands of radio waves that are supposed to be protected for studying the universe can get messed up by things like signals, leaky equipment reflections from surfaces, signals coming down from satellites and random transmitters that we do not expect to be there. Radio emissions are really everywhere in life and they can cause problems, for radio astronomy bands.

The worst part is that Radio Frequency Interference can look like a signal, from the sky. For example:

A satellite is able to create a signal that’s very narrow and it moves up and down in frequency. This signal from the satellite is special because it does not cover a range of frequencies it is a narrowband signal from the satellite. The frequency of the signal, from the satellite changes so it is not always the same.

When light reflects off an aircraft it can make flashes of light that do not last very long. These flashes of light are like spikes that happen because of the reflections off the aircraft. The reflections, off the aircraft are what cause these spikes.

I have seen that local electronics are able to produce patterns that repeat. These repeating patterns can be really interesting when you look at them. Local electronics can do this because of the way they are made. Local electronics are good, at producing repeating patterns.

That is why a critical test is doing it all over again on our own: can another telescope at a time look at the same spot in the sky and see the same thing again with the same telescope not being used but another one is used so the telescope is not the same the time is not the same but the sky coordinates are the same, for the telescope.

If you cannot repeat it you cannot easily tell the difference between a one-time event, a local glitch and a distant transmitter that was only on for a short time. The thing is, if you cannot repeat it how can you really know what a one-time cosmic event or a local glitch or a distant transmitter that happened to be, on briefly really is. You have to be able to repeat it to figure out what is going on with a one-time event or a local glitch or a distant transmitter.

Having 100 shortlisted candidates is actually a thing. It is a number of people to deal with. You can easily follow up with these candidates. Check them out. You can also watch them closely to see what they are like. This makes it easier to make a decision, about the candidates. Having 100 shortlisted candidates is not bad all.

6) Why FAST is central to the next step

Arecibo is gone so where do you go for a follow-up on this. The people, in charge are looking at the 100 candidates. They are using Chinas FAST, which’s the Five-hundred-meter Aperture Spherical Telescope, to do this. The FAST is now the worlds single-dish radio telescope. So the 100 top candidates are being examined using the radio telescope.

FAST matters because:

This thing is really good, at picking up signals because it has a big area that collects them. The sensitivity of this thing is very high.

The telescope can look at parts of the sky. It can do targeted observations of sky positions like a particular star or planet. This means it can focus on sky positions and get a lot of information, about them.

It can try to find things again. This is the way to make something that seems interesting into something that people really believe in. The gold standard, for this is repeat detections of the thing that seems interesting.

So we can use a telescope to see if something is special to the place where Arecibo is or if it is just the equipment they are using. If we see the thing at FAST and it looks the same and is in the spot, in the sky then we can be a lot more sure that it is real.

Even then it still would not instantly mean aliens. It would mean this signal is behaving unlike interference so we should investigate the signal intensely. We should look into the signal carefully because the signal is behaving unlike common interference. The signal is what we need to investigate.

7) What these signals are probably going to be most of them will be pretty ordinary and that is perfectly fine these signals are likely to be things that happen every day. That is okay these signals.

Most of the 100 will probably have an explanation. What usually happens to SETI candidates is:

A) There are some things that people made that you did not notice at first these human-made sources that you did not notice at first like human-made sources that you did not think about when you started. Human-made sources can be a lot of things and these human-made sources that you did not identify at first can be really important.

Radio Frequency Interference is sometimes really tricky to spot. You might not even notice Radio Frequency Interference until you look at lots of examples or check some databases that show how frequencies are used. Radio Frequency Interference can be sneaky, like that.

B) Natural astrophysical phenomena

A narrow feature might come from a maser line. This natural maser line is a thing that happens in space.. A transient could come from a flare. A flare is, like a burst of energy. It could also come from a rotating object. The thing is many natural sources have signatures that can look like they were made by people until we study them carefully. We have to look at the maser line and the flare and the rotating object really closely to understand what is going on with the natural sources.

C) One-off statistical or processing artifacts

When you do a search you often get wrong results. If you look at a lot of information you will come across things that seem important but are really just coincidence. The large searches will generate these positives because if you test enough data you will find rare patterns in the data that look like they mean something but are actually just luck.

The main thing to remember is that finding explanations is not a bad thing. This is actually how science works. When we look for explanations we get some good things out of it like better pipelines, better ways to reject Radio Frequency Interference and a better understanding of radio backgrounds. These things make it easier for the Search for Extraterrestrial Intelligence or SETI to find what it is looking for in the future. The Search, for Extraterrestrial Intelligence or SETI will be more powerful because of this.

That is part of why researchers describe the project as establishing sensitivity thresholds and lessons for future surveys even without a confirmed alien detection from the aliens. The project is really, about finding these sensitivity thresholds and learning lessons that can be used for surveys to find aliens.

8) The thing about the Arecibo and SETI at home project is that it is really bigger than wondering if we found aliens. The Arecibo and SETI at home project is about something

The Arecibo and SETI at home project is very important because it helps us think about the Arecibo and SETI at home project in a way.

We should think about what the Arecibo and SETI at home project means to us and how it affects our lives.

The Arecibo and SETI at home project is not about the question of did we find aliens it is about the Arecibo and SETI, at home project itself.

Even if every single one of the 100 signals is finally figured out the historical impact of SETI@home is really huge. SETI@home has made a difference in the past.

Citizen science at internet scale

The SETI@home project showed that a lot of people are willing to help with science work if you make it easy to understand and interesting. This project inspired big projects in physics, biology, climate modeling and SETI@home type of projects. These projects were also able to get a lot of people to participate because they were made accessible and meaningful to millions of people who were interested, in SETI@home and other science projects.

Methods development

The pipeline improvements like signal scoring and Doppler drift searching and interference filtering do not just disappear.

These pipeline improvements have an effect, on how radio astronomy deals with amounts of data.

This is particularly true as telescopes get better. Surveys become more regular and ongoing.

The pipeline improvements influence radio astronomy when it has to handle data volumes.

Cultural impact

The SETI@home project made people feel like they were really a part of the search for life beyond Earth. This was not, about reading books on science. People were actually doing science with SETI@home. They were part of the SETI@home machinery that was working to find life beyond Earth.

Now we are at the end of this big search. The story has changed. It used to be about lots of home computers searching. Now it is about professionals using better equipment to follow up on the best possibilities. They are using these facilities to do a more careful search, for the search results that the home computers found. The search is still going on. Now the professionals are doing it with the new facilities.

9) So scientists are going to test these one hundred candidates for something. They want to see what the candidates are made of. The scientists will put the one hundred candidates through a lot of tests to find out more about the candidates. The tests will help the scientists understand the candidates better. The scientists are really interested, in the one hundred candidates. They want to learn as much as they can about the candidates.

Following up is not just looking through a telescope. Hoping for something. It is a system. The usual things people do are:

Step 1: Re-observe the same sky coordinates

The FAST telescope or other telescopes will look at the spot and wait for the same kind of signals. If the FAST telescope sees a signal from the place again that is a big deal. The FAST telescope is really good, at finding these signals so if it finds one again that means something.

Step 2: Off-source checks

People will also look at the sky around those positions. If the signal is coming from all directions then the problem is probably something, by that is causing trouble, like local interference. The signal and local interference are important to consider when looking at the sky positions and the signal.

Step 3: Frequency and drift verification

A distant transmitter that seems real might have patterns that look like it is moving around something or spinning. If the drift does not look the same every time we detect the transmitter then the transmitter is probably close, to us not away like we thought.

Step 4: Multi-observatory confirmation

The best proof that something is real comes from lots of telescopes that’re really far apart from each other. These telescopes are looking at the part of the sky and they are all seeing the same thing. If that happens it is very unlikely that what they are seeing is something wrong with the equipment. The telescopes are detecting the signal from the same sky direction. This is a strong sign that the signal is real and not just local interference from the telescopes themselves. Local interference is when something, near the telescope is messing with the signal.. If lots of telescopes are seeing the same thing then local interference is probably not the problem. The chance of interference drops dramatically when multiple geographically separated telescopes are detecting the same signal from the same sky direction.

Step 5: We need to rule out the things that we already know are giving off signals, the known emitters. This is a step because we have to make sure that the signal we are getting is not coming from something that we already know about like a known emitter. We do not want to get confused and think that a signal is coming from somewhere that it is not so we have to rule out these known emitters. The known emitters have to be checked. Then we can move on to the next step.

People who study these things check with information, from satellites, aviation sources and lists of frequency allocations. Nowadays computer programs are also helping to match up times with sources of Radio Frequency Interference or RFI sources.

This is when you really start to think about how possible it’s that we will find signs of technology from other worlds what people call “technosignature plausibility” and you begin to have a serious conversation, about “technosignature plausibility”.

10) Let us take a moment to think about this: what would a real sign of technology, from else actually look like?

A classic SETI technosignature expectation is a signal that keeps going and does not change much in frequency. This kind of signal is good for communication because it is strong and easy to hear. It also stands out from all the noise that is out there in the universe. The reason we think this is because narrowband signals are better for talking to each other over distances. SETI technosignature is what we are looking for when we want to find out if we are alone. SETI technosignature is, like a message that says hello we are here.

But there are many possibilities:

A civilization could be using ways to communicate that we have not figured out yet. The civilization might be using these methods. We are not aware of them. We just do not know what methods of communication the civilization is using.

Signals could be brief, directional, or rare.

These things could be mistakes from radars, than messages that people are trying to send on purpose. The signals could be coming from radars by accident. Not because someone is trying to communicate with us. These signals are what people call “leakage” from radars.

The signals from them might be coming in on frequencies that we have not looked at closely. We need to think about the fact that these signals might be, on frequency ranges that we have not searched deeply.

This uncertainty is the reason why huge surveysre important: they help us look at a very large number of possibilities. Huge surveys are like a help to us because they let us see many different things that could happen. They are important, for understanding the number of possibilities that exist. Huge surveys give us a way to deal with this uncertainty by looking at different things at the same time.

At the time this is also why caution is really important: when you do not know the target you can easily fool yourself about the target.

11) What the search concludes really means is that the people who are doing the search have finally found what they are looking for. The search concludes when the people who are searching have got the answer they need. This is what the search concludes is, about. The search. That is it.

When the search concludes the people can stop looking. The search. They have the information they want. The search. Everything is okay.

The search concludes is a deal. The search. People are happy. The search. That is the end of it.

News headlines can be really scary. It sounds like the SETI project is coming to an end.. The truth is, the SETI project is not stopping. The SETI project is still going on.

What is coming to an end is a part: the main SETI@home analysis of archived Arecibo data and the long process of going through billions of detections to get a final short list of SETI@home detections. The SETI@home team is finishing up this phase of SETI@home analysis.

The search is still going on in a lot of areas too:

New telescopes (FAST, MeerKAT, upcoming SKA components, and other arrays)

Dedicated SETI instruments and surveys

Better signal processing and machine learning methods

More open data and collaborative pipelines

So SETI@home is like a project that went out and came back with some things to look at. Now the scientists are doing the work in the lab. They are looking closely at the best things they found using better tools. This is like using a good microscope to see what SETI@home found. The scientists are taking a look, at the things that SETI@home discovered.

12) Why this news is important, at this moment

This story is getting a lot of attention in mid-January 2026. The reason is that many news outlets and institutional sources think it is a deal. They see it as a milestone for a famous project that has been going on for a long time. This project has finally released its big thing. A list of 100 candidates. Now the project is passing the step, to newer and better facilities. The project is a part of our culture and a lot of people are talking about it.

This is a special moment, in science. It is not one big discovery but the end of a very long process. The results are put together in a way that makes it clear what we need to do. The results of the process are now easy to understand and use for the next steps. Science is full of discoveries but this is different. This is the completion of an amount of work and now we have the results of this enormous process.

And this is also a reminder of something that’s really beautiful: millions of ordinary people helped with a piece of a search that goes on for a very long time and covers a huge distance I mean light-years. The search spans years and millions of ordinary people did a part of it.

13). Did they actually find aliens then?

They have not found any proof yet. The situation now is:

The people, in charge are taking a close look at one hundred candidates. They want to make sure these one hundred candidates are good enough. The one hundred candidates are being checked carefully.

We need to keep watching and see what happens next we will also use FAST to check if anything weird happens again and we cannot explain it as interference from something else so we are trying to figure out if these things are really happening or if it is just the FAST equipment interfering with our results and if these things, with the FAST equipment keep happening.

Most things can probably be explained,. The thing about searching for extraterrestrial life is that even if the chance is really small it is still worth looking into carefully. The point of doing this is to see if we can find anything that’s not from our planet. Searching for life is what this is all, about and that is why we have to check everything even if it seems like a long shot.

The honest scientific stance here is that these things are really interesting. They are not proven yet. The scientific stance, on this is that it is intriguing not proven.

14) What to watch for next (the signs of a real breakthrough)

If you want to see if this story gets really big look out for these things that might happen:

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Repeat detection of a candidate from the same sky position.

Confirmation by more than one observatory.

It is very clear that this thing is not connected to any satellites or aircraft or anything on the ground. The evidence shows that it does not come from known sources like satellites or aircraft or things, on the ground.

This signal is really interesting because it shows a pattern that is very similar to what we see when something is moving really far away. The Doppler behavior of the signal is consistent, with something that is coming from a source. The signal is basically telling us that it is coming from far away.

Peer-reviewed publication detailing the signal properties and elimination of alternative explanations.

If any candidate reaches steps 1–3, it becomes extremely interesting. Steps 4–5 would be the path toward a serious techno signature claim.