In what’s being called a “record-breaking exoplanet discovery” NASA announced today the detection of not one, not two, not three or four but seven exoplanets orbiting the ultra-cool dwarf star TRAPPIST-1, located just under 40 light-years away in the constellation Aquarius. (That’s astronomically very close, although still 235 trillion miles distant.) What’s more, these exoplanets aren’t bloated hot Jupiters or frigid Neptune-like worlds but rather dense, rocky planets similar in size to Earth…and at least three of them are well-positioned around their dim red star to permit liquid water to exist on their surfaces.
TRAPPIST-1 and its planets are like a miniature version of our inner Solar System; the star itself is only slightly larger than Jupiter with a mass about 8% of our Sun, and the planets B through H all have orbits smaller than the diameter of Mercury’s. Still, even an ultra-cool dwarf star has a habitable zone, and three of these planets lie within it. The others may very well also possess habitable regions on or inside them too.
“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington, D.C. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”
The seven-planet system was confirmed through (and named for) the ground-based TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) telescope as well as observations from NASA’s Spitzer Space Telescope.
“This is the most exciting result I have seen in the 14 years of Spitzer operations,” said Sean Carey, manager of NASA’s Spitzer Science Center at Caltech/IPAC in Pasadena. “Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets.”
Like anything else, stars have life spans. They are born (from collapsing clouds of interstellar dust), they go through a long main phase where they fuse various elements in their cores, and eventually they die when they run out of fuel. The finer details of these steps are based on what the star is made of, how massive it is, and what sort of company it keeps. Stars like our Sun have lifespans in the 9-10 billion year range—of which ours is near the middle—but other stars can have much shorter or longer lifespans, and as astronomers look out into the galaxy they can find stars at all different phases of their lives…of course, the longer a phase lasts, the more likely it is to find stars existing within it. We’ve found stars that are only a few thousand years old and we know of regions where stars are, right now, in the process of being born, but what is the oldest star we know of?
Actually, it’s not all that far away, in cosmic terms. Just 190 light-years distant in our own galaxy, HD 140283 (aka the Methuselah star) is, as of 2013, the oldest star ever discovered. Based on its stage as a subgiant and its remarkably low amount of heavy elements, astronomers have estimated the age of this star as 14.3 billion years old. Now this number is actually more than the estimated age of the Universe itself, but don’t worry—there’s a reason for that.
Read the rest of this story by astronomer Phil Plait on Slate here: The Oldest Known Star in the Universe.
It hasn’t even been found yet (they’re still working on that) but the recently-announced Planet Nine is already spurring discussion amongst the world’s astronomers. One of the recent topics surrounding this alleged new planet is (again, besides where it’s hiding) how it formed and how it got into the incredibly distant orbit it’s thought to be in. Estimated to be nearly as massive as Neptune, and possibly similarly gaseous as well, Planet Nine would be an anomaly among the small frozen balls of ice that typically haunt the outer Solar System. Recently, a team of scientists decided to investigate the possibility that Planet Nine did not originate in our Solar System at all but rather was captured from another star, back when the Sun’s stellar family was much closer together… and apparently much more trusting. (That’ll teach ’em.)
Our Sun may be made up of 98% hydrogen and helium but the remaining two percent comprises many other elements, detectable by their unique absorption lines within the gamut of white light we receive on Earth. One of those elements is calcium, which exists in ionized form in relatively tiny amounts in the Sun’s chromosphere – but still enough to allow images to be made using special filters aligned to the wavelength of its absorption line. And this is precisely what photographer Alan Friedman did on April 12, 2015 when he captured the image above!
Neutron stars are strange cosmic beasts. Stellar corpses that are several times the mass of our Sun but only about the width of Manhattan, they can contain a mountain’s worth of star-stuff within the space of a sugar cube, creating all sorts of weird physics that requires funny-sounding names like “quark-gluon plasma” to even try to describe what’s going on. The video above, created by Munich-based design studio Kurzgesagt (which means “in a nutshell” in German) illustrates how neutron stars form and what we think is happening on, around, and inside them.
See more In a Nutshell videos by Kurzgesagt on YouTube here, and find some interesting neutron star facts below:
It really is. I mean, nevermind that it comprises over 99% of all the mass in our solar system, that it supplies our planet with the energy needed to sustain life on its surface, that its constantly-blowing solar wind helps keep some of those nasty cosmic particles out of the planetary neighborhood, and that it makes a bright sunshiny day even possible (but remember to wear sunscreen!)… in addition to all that, it’s also just really, really cool.
Watch the video above and you’ll see what I mean.