Barring some tragic accident, I expect to see, in the next 6 years, a news broadcast announcing that scientists have discovered an earth-sized planet around another star with an oxygen-rich atmosphere.
Meaning . . . the planet probably has an abundance of plants.
This doesn't mean forests and swamps and petunias. It could just be one-celled plants. However, the planet is chemically active in ways that convert carbon dioxide to oxygen on a large scale.
Within the next 6 years.
That's not a prediction, by the way. But it is not a guess either. I suspect scientists will turn their attention to the most likely planet candidates discovered in the next three years, and it will take another three years to collect and interpret the data.
In making this claim, I am referencing the work of the Kepler observatory - a floating infrared telescope build to detect planets around other stars. It is currently monitoring over 100,000 stars for some of the indicators of planets.
It looks for stars that "dim" on a regular basis as its planets pass between us and the star. In effect, the planet "eclipses" a small part of the star, causing the star to dim by a small but measurable amount.
The first 6 weeks of data from the Kepler Observatory has yielded over 700 planet candidates, of which nearly 150 are candidate earth-sized planets.
Some of these might not be planets. They might be sunspots - or, starspots. They might be just natural fluctuations in the brightness of the star. They might be extra-terrestrial pranksters playing tricks on us. There are other options.
On the other side of the equation, the methods that allow us to discover these planets also allows us to discover the possibility of earth-sized moons around some of the other planets. The planet might be too big to hold life, but the moons present other possibilities.
Of those that have planets, for them to have plants they also have to be the right distance from the parent star so as to be not to hot and not too cold. They have to be old enough for life to evolved. They have to have avoided the types of collisions with other proto-planets that could destroy life. It has to avoid evolving a species that would have turned the planet into a radioactive cinder.
But if they are planets or planet-sized moons, because those planets eclipse their parent starts, light passes through the planet's atmosphere to get to us. The gasses in the atmosphere will absorb some of that sunlight and, when we look at what reaches us, we should be able to tell if there is oxygen in that atmosphere.
Which means an announcement of the discovery of an earth-sized planet far enough from its parent star to have a comfortable temperature with an oxygen-rich atmosphere could be just around the corner.
Okay, maybe around two corners.
This, by the way, is the marvel of science. Try to look in a holy book or pray to some deity and discover whether there are planets orbiting around other stars - their size, their distance from the star, the chemical composition of their atmospheres. Some people like to say that science is a "faith". In fact, science is a reliable way of making accurate predictions of what is going to happen next. It works a lot better then entrails and the types of visions one gets when one has gone too long without food and water.
It also means one other thing.
If it is this easy for us to discover an oxygen-rich earth-sized planet floating around in space.
Then it is just as easy for them to discover us.
For quite a couple of billion years at least, Earth has been broadcasting a signal to the rest of the universe that flashes the sign, "Living Planet!", to anybody who can read the language of science.
Has anybody . . . anything . . . yet read the sign?