Phil Plait seemed to appreciate the news just as much. His Discover headline read in all-caps, “ALPHA CENTAURI HAS A PLANET!”

Let’s analyze all of this excitement…

Yesterday, astronomers announced they discovered an Earth-sized planet orbiting Alpha Centauri. The finding is also published in Nature today.

Alpha Centauri lies only 4.3 light-years away—closer than any other star system. And it’s not one star but three—two binary stars similar to the Sun orbiting close to each other, called Alpha Centauri A and B, plus a more distant and faint red companion known as Proxima Centauri. Since the nineteenth century, astronomers have speculated about planets orbiting these bodies, the closest possible abodes for life beyond the Solar System, but searches of increasing precision had revealed nothing. Until now.

“Our observations extended over more than four years using the HARPS instrument and have revealed a tiny, but real, signal from a planet orbiting Alpha Centauri B every 3.2 days,” says Xavier Dumusque, lead author of the paper. “It’s an extraordinary discovery and it has pushed our technique to the limit!”

A period of 3.2 days means that this new planet orbits extremely close to its parent star, “roasting at perhaps 2,200 degrees Fahrenheit with a surface likely composed of molten lava,” writes Adam Mann in Wired. Not exactly a hospitable neighbor! (Sorry, Mr. Rogers.)

This news comes right on the heels of another exoplanet discovery. On Monday, our friends at Zooniverse announced the first ever confirmed exoplanet discovered by the citizen scientists at Planet Hunters—a gas giant dubbed “PH1” with a radius about 6.2 times that of Earth, making it a bit bigger than Neptune. PH1 resides in a four-star system—twin suns that in turn are orbited by a second distant pair of stars.

These discoveries provide further evidence that, with the number of eyeballs looking for exoplanets (professional astronomers and citizen scientists alike), an Earth-like exoplanet can’t be far off. Again from the Bad Astronomer:

…we’re zeroing in on Terra Nova, folks, and statistically speaking there should be millions of them in the galaxy. It’s only a matter of time before we find the first one.

Image: ESO/L. Calçada

The galaxy was actually revealed in a Hubble photograph in 2009. It was a very faint light among very bold and bright galaxies. 

It might have become irrelevant, but a ground-based telescope took another look. From  ScienceNow:

To measure the distance to the galaxy, lead author Matthew Lehnert of the Paris Observatory, Nicole Nesvadba of the University of Paris, and their colleagues took a spectrum of the object using a spectrograph mounted on the European Southern Observatory’s Very Large Telescope in Chile. By analyzing the spectrum, the researchers determined that the galaxy had a red shift of 8.55, corresponding to a distance of 13.1 billion light-years.

Nesvadba sums up this work in a press release:

Measuring the redshift of the most distant galaxy so far is very exciting in itself, but the astrophysical implications of this detection are even more important. This is the first time we know for sure that we are looking at one of the galaxies that cleared out the fog which had filled the very early Universe.

When the Universe was about 400 million years old, it began to go through what scientists call the reionization era. Universe Today and Bad Astronomy have good descriptions of this era, and a supporting article in Nature puts it most succinctly:

According to astronomers’ best models, the early Universe burst out of the Big Bang around 13 billion years ago as an ionized fireball. This ball of gas gradually cooled, becoming neutral as protons and neutrons combined to form hydrogen. “Then stars and galaxies began to form, lighting up the Universe, heating up the gas and reionizing it,” says Lehnert. “This galaxy allows us to peek at the reionization era.”

Published in the July 8 edition of the journal Nature, the finding is remarkable considering it was discovered by scientists who were looking at remnants from a supernova explosion.

Microquasars, as these objects are called, are not that uncommon. Universe Today points out that there are a dozen or so in our own Milky Way Galaxy. But the impressive size of this particular bubble, estimated at 1,000 light years across, makes it stand out from the crowd. Most microquasars in our own galaxy are less than 10 light years wide.

According to Universe Today, microquasars are formed by two objects—in this case, the small black hole and a companion star. Energy is produced

by matter falling from one component to the other, and can produce jets of high-speed particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expanding bubble made of hot gas and ultra-fast particles colliding at different temperatures.

The jets seen in this microquasar are surprising and may alter the idea of how energy is emitted by a black hole. As New Scientist reports:

These jets are much more powerful than expected for a black hole of this size, blowing bubbles that expand faster than the speed of sound. The finding suggests that more of the energy spent by a black hole goes into accelerating matter– rather than emitting x-rays– than previously supposed.

Data in the form of x-ray emissions were gathered from both the European Southern Observatory and the Chandra X-ray Observatory in the study. Giant bubble-blowing black holes like this microquasar may help scientists better understand differences between black holes of different sizes—including the ones that lurk at the centers of most galaxies like our own.