Recently the exquisite JWST has possibly detected a signature for life beyond our solar system (On exoplanet K2-18b). If this can be followed up with a value of 5 on the scientific sigma scale then humanity may have just discovered that we are not alone...!
Let me explain - Dimethyl Sulphide which produces a cabbage-like smell is a by-product of marine phytoplankton and this is practically the only way it is produced on Earth. But as usual we will need to do follow up research as it has also been detected in comet tails. To quote Wikipedia: " However, dimethyl sulfide has been detected in abiotic sources such as comet 67P/Churyumov-Gerasimenko. The European Space Agency has directly sampled the cloud of dust and gas shed from the comet.[37][38] Dimethyl sulfide has also been made abiotically in laboratories using prebiotic conditions.[39] Such discoveries has led to some doubt about dimethyl sulfide being a clear biosignal for life on other planets.[40][41] "
How magnificent that in the space of 30 years we have gone from thinking the only planets that exist are in our solar system - to being able to sample the spectra of thousand's of exoplanets...!