Studying 51 Eridani b should help scientists understand how our Solar System formed.
HD 219134b is much closer: a little over 21 light-years away, in the constellation Cassiopeia. It's a rocky world, like Earth; but larger, and blistering hot. It's also the closest transiting exoplanet we've found so far. This is a big deal, at least for scientists who study planets.
- "An Infant Version of Jupiter"
- HD 219134b: Close, Hot, and 'Worth its Weight in Gold'
A Twitter blurb for "Pluto, Earth 2.0, and Life in the Universe" said that the post is about "science, knowledge, and God."
Responding to it, someone asked me why I "include gods in a discussion of evidence-based science. It has no place there." (August 5, 2015)
It was, I think, a reasonable question: particularly for someone immersed in contemporary American culture.
Last week, that thought started me talking about Anaximander and Non Sequitur's Eddie. (August 7, 2015)
I'm getting over a cold this week, which may explain my remembering Danae's science report. And that's another topic.
Loudly-Christian folks are often either stridently opposed to the evils of science: or peddling 'Bible science,' which is about as accurate as their perennial 'end times' Bible prophecies. (April 19, 2015)
I think the folks who occasionally warn me that I'll burn in everlasting hellfire because I'm Catholic mean well. I'm also quite sure that they're wrong. Catholics don't worship Mary, and I really do not think that the Almighty follows Ussher's timetable.
As a Catholic, I must believe that the universe is a place of order and beauty, constantly upheld and sustained by God, in a "state of journeying" toward an ultimate perfection. (Catechism of the Catholic Church, 32, 302)
Because the universe follows knowable rules, we can study phenomena and learn how the universe works. Scientific discoveries are invitations "to even greater admiration for the greatness of the Creator." (Catechism, 283, 337, 341)
We're rational creatures, created in the image of God, "little less than a god:" with the power and frightening responsibilities that come with our nature. (Genesis 1:26-27, 2:7; Psalms 8:6; Catechism, 355-373, 2402, 2415-2418, 2456)
But using our brains is optional.
We have free will, so we can act as if the natural order and nature's Creator matter: or not. (Catechism, 311, 396)
I don't have a problem with accepting reality, since I believe God creates the universe and is competent. I keep quoting Leo XIII:
"...God, the Creator and Ruler of all things, is also the Author of the Scriptures - and that therefore nothing can be proved either by physical science or archaeology which can really contradict the Scriptures. ... Even if the difficulty is after all not cleared up and the discrepancy seems to remain, the contest must not be abandoned; truth cannot contradict truth...."We're learning that the universe is huge and almost-unimaginably ancient, which is fine by me. I see what we're learning as invitations to "greater admiration for the greatness of the Creator."
("Providentissimus Deus,"1 Pope Leo XIII (November 18, 1893) [emphasis mine])
I might not have imagined a universe on this scale: but I'm not God, not by a long shot. I'll get back to that idea.
My wife was reading — studying, actually — Philippians the other day. Nothing unusual about that: we're both Catholics, so Sacred Scripture is part of our lives.
"The Church 'forcefully and specifically exhorts all the Christian faithful. . . to learn the surpassing knowledge of Jesus Christ, by frequent reading of the divine Scriptures. Ignorance of the Scriptures is ignorance of Christ.112"However, we're Catholics, so we don't think the Bible is a science textbook: or a software user's manual, for that matter. (January 14, 2011)
This is one of the best short descriptions of the Bible that I've seen:
"...Know what the Bible is – and what it isn't. The Bible is the story of God's relationship with the people he has called to himself. It is not intended to be read as history text, a science book, or a political manifesto. In the Bible, God teaches us the truths that we need for the sake of our salvation...."Studying this universe, and using what we learn to develop new tools, is in our nature. It's what we do. Ethics matter, of course, but science and technology are not transgressions: they're part of being human. (Catechism, 2292-2296)
("Understanding the Bible," Mary Elizabeth Sperry, USCCB)
Putting the universe, science, Katy Perry — anything or anyone other than God — in God's place is a bad idea. It's called idolatry, and we shouldn't do it. (Catechism, 2112-2114)
But acknowledging that folks didn't know everything, back when Merit-Ptah and Imhotep practiced medicine? That's reasonable.
Since then, Kubaba and Ur-Zababa's Sumer became part of Sargon of Akkad's Akkadian Empire: whose merchants probably traded with the vast Indus Valley Civilization.
We don't know the Indus Valley Civilization's name, or what folks called its great cities: Lothal, Mohendo-daro, and Harappa.
Lothal and Mohendo-daro mean 'the mound of the dead' in local languages, and Harappa is the name of a village and railway station near the ruins.
We know more about the Mesopotamian civilizations, partly because they left records baked onto clay tablets; and partly because descendants of Abraham lived there. Imagery in 1 Samuel 2:8 and Psalms 148:4 is beautiful, poetic, and consistent with Mesopotamian cosmology.
About two millennia after Kubaba, folks like Thales of Miletus and Aristotle started studying nature systematically.
Socrates was notorious for asking questions, but not giving answers. He eventually asked too many questions about something the oracle at Delphi said, was convicted of "not believing in the gods of the state," and told to drink hemlock. Which he did. And that's yet another topic.
Two dozen centuries later, We've learned that Aristotle was right about Earth changing, but wrong about aether.
Around the time when the Hanseatic League started bringing a measure of peace and prosperity to the Baltic — or opposing my viking ancestors' cherished traditions — some European scholars said that Earth might not be the only world.
Aristotle's fan base insisted that Earth was the only world: because Aristotle said so.
In 1277, the Church told scholars that if God decided there are other worlds, what Aristotle said won't change the facts.
The 219 Propositions of 1277 were later annulled, but not the principle that God's God: Aristotle's not. (September 26, 2014; February 23, 2014)
We've learned quite a bit since then. 'Barbarous' architectural technology made Gothic cathedrals possible, a Dublin-born Calvinist said the first day of creation started at nightfall on Saturday, October 22, 4004 BC, and Nicolas Steno — a pioneer in anatomy and geology — questioned assumptions about fossils. Turns out, Steno was right: Fossils don't grow in the ground.
Galileo's abrasive personality and stubbornness annoyed the powers that be; "De revolutionibus orbium coelestium" was blacklisted for a while, but Copernicus wasn't; and Darwin's "Origin of Species" never made it into the "Index Librorum Prohibitorum." (June 14, 2015)
The Index itself was put on the shelf, metaphorically speaking, in 1966. That probably upset tightly-wound Catholics. I try to avoid confusing nostalgia for tradition, and that's another yet gain topic. (July 5, 2015; July 18, 2014)
I'm forgetting something. Let's see: truth; science and technology; the Hanseatic League; nostalgia and confusion. Right.
Like I said: I'm not God, not by a long shot. I'm human: a creature made from the stuff of this world and in the image of God; "little less than a god," but most emphatically a creature, not the Creator. (Genesis 1:26-27, 2:7; Psalms 8:6; Psalms 111:10)
"Fear of the Lord" in Psalms 111:10 isn't the blind panic touted by overly-enthusiastic disciples of Johathan Edwards. It's more like reverence: recognizing that God's God, and I'm not. (Footnote 6 to Psalms 111, NAB)
I've talked about humility, science, and getting a grip, before. (March 29, 2015; August 10, 2014)
Expecting science and technology to solve all our problems was silly: and so is the more recent assumption that we're all gonna die because we've been using our brains.
Yes, we've made mistakes: big ones. We'll be cleaning up the mess left by 19th century industrial growth for generations. We're learning that 20th century reliance on fossil fuels can't continue, and that nuclear power isn't a panacea.
But if anything, we're smarter than we were when Oldowan tools were the latest thing in high tech. We're surviving one of Earth's glacial epochs, so I think we can deal with McCormic reapers, Roombas, and whatever we make next. (June 12, 2015; December 12, 2014; July 11, 2014)
As centuries and millennia roll by, I'm quite sure that we'll solve some problems, defer others, and — some of us — try to ignore the rest.
Folks living in the 67th century won't live in a perfect world: but returning to the imagined ideal of the 66th won't solve their problems. And that's still more topics. (May 3, 2015; October 12, 2014)
I'm also quite certain that they'll have learned more about this universe, and still have a great deal left to learn.
(From NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team; used w/o permission.)
(From D. Futselaar, F. Marchis, SETI Institute; via BBC News; used w/o permission.)
("The young, Jupiter-like world could yield clues to the formation of our own Solar System"
"Young 'alien Jupiter' planet discovered"I suppose most folks realize that expressions like 'a dozen pigeons' and 'a hundred squirrels' don't necessarily mean that there were exactly 12 or 100 of the critters. On the other hand, we expect 12 eggs to be in a carton marked 'one dozen eggs,' and that's almost another topic.
BBC News (August 14, 2015)
"A planet 100 light-years away resembles an infant version of Jupiter, astronomers say.
"The new world, known as 51 Eridani b, is only 20 million years old - a toddler by astronomical standards.
"The alien world could yield clues to the formation of our Solar System, which has an unusual lay-out.
"The find was made by the Gemini Planet Imager (GPI), which looks for faint, young planets orbiting bright, relatively nearby stars.
"The new world shows the strongest methane signature ever detected on an alien planet. Previous Jupiter-like exoplanets have shown only faint traces of methane, making them very different from the heavy methane atmospheres of gas giants in our Solar System.
"The astronomers also detected water, using GPI's spectrometer instrument.
"These findings indicate that it might be similar to planets in our Solar System, yielding additional clues to the formation of giant, astronomical bodies...."
The first two paragraphs of this unsigned article are pretty close to being accurate.
51 Eridani is around 96 to 97 light-years away. It's part of the Beta Pictoris moving group; a set of 17 stars and PSO J318.5-22, a 'rogue planet' that's not circling a star.
51 Eridani is roughly 20 million years old.
Eric E. Mamajek and Cameron P. M. Bell's "On the age of the β Pictoris moving group" pegs the group's age at 23,000,000 years, give or take a substantial margin. It's a main sequence F0 V star: hotter and brighter than our sun, but otherwise quite similar.
Maybe our Solar System really does have "an unusual lay-out." Many planetary systems found so far have Jupiter-size-and-up planets orbiting close to their stars. Maybe that really is the norm; and our home's setup, with small rocky planets close to the star and giants farther out, is unusual.
Then again, maybe not. UCLA's James Larkin, quoted later in the article, points out that 'hot Jupiters' have been easier to spot. I'll get to that, and the best picture so far of 51 Eridani b.
(From J. Rameau (UDEM), C. Marois (NRC Herzberg); via BBC News; used w/o permission.)
("The GPI detects alien planets through a process of direct imaging"
"...The vast majority of alien solar systems that have been discovered are very different from our own, with massive planets - so-called "hot Jupiters" - orbiting close to their stars. This is partly because such systems are easier to detect with the techniques currently used to search for planets orbiting distant stars.Artist's concepts/impressions, like that picture of 51 Eridani b, catch a reader's eye: which is important for news services. They also tell folks what something probably looks like.
" 'Previous search methods couldn't find systems like our own, with small, rocky worlds close to their star and large, gas giants at large distances like Jupiter and Saturn,' said co-author James Larkin, from the University of California, Los Angeles (UCLA)....
"...Astronomers believe the gas giants in our Solar System formed slowly - by building up a large core over a few million years and then pulling in a huge amount of hydrogen and other gases to form an atmosphere. This is known as a 'cold-start'.
"But the Jupiter-like exoplanets that have been discovered so far are much hotter than models have predicted. This hints that they could have formed quickly - as gas collapses to make a scorching planet in what is known as a 'hot-start'...."
The blotchy picture, with markings showing the size of Saturn's orbit around our sun and 51 Eridani b's position, is what scientists actually 'see.' It's a photo taken in near-infrared light on December 18, 2014; processed for human eyes.
Gemini is an international consortium. Their website lists six members: Argentina, Australia, Brazil, Canada, Chile, and the United States. Their telescopes are on two of Earth's best spots for observatories: Hawai'i and Chile.
My guess is that mountain tops near Lhasa would be good for astronomers, too: but that may have to wait until we have better transportation in that part of the world, and the political situations settle down.
Getting back to science and 51 Eridani b, Gemini Observatory's press release includes an animation, showing the images in order of increasing wavelength from 1.5 to 1.8 microns. The animation's caption gives a pretty good description of how the process works.
51 Eridani b's sun is about a million times brighter than the planet, which is why the GPI (Gemini Planet Imager) system includes a coronagraph. Bernard Lyot made the first cornoagraph in 1931, which made observing our sun's corona possible between solar eclipses.
A coronagraph blocks light from our sun or another star, letting astronomers see things that would be lost in the star's glare otherwise. It's the same principle we use when we shade our eyes to look at something close to the sun.
51 Eridani b isn't the first exoplanet astronomers have 'seen.' That's 2M1207b, discovered in 2004. Fomalhaut b is the first one imaged in visible light.
Fomalhaut b is less than three times Jupiter's mass, and might be only as massive Earth. The last I checked, astronomers still don't have enough data to be sure.
If it's a gas giant, Formalhaut b should be only slightly younger than Fomalhaut: very roughly 450,000,000 years old.
51 Eridani b is a very young planet — around 20,000,000 years old — and close enough for scientists to study. Even better, it's about as far from its sun as the Solar System's gas giants.
That, and 51 Eridani b's methane and water, make the 51 Eridani system a very close match to our planetary system: as it was some 4,540,000,000 years ago. That makes it very important for scientists trying to learn how the Solar System formed.
"...The core build-up process can also form rocky planets like the Earth. But the fast collapse process might only make giant gas planets. The planets in our Solar System are 4.5 billion years old, but at just 20 million years old, 51 Eridani b might be young enough to reveal clues about how it was created.More, mostly about 51 Eridani b:
" 'This planet really could have formed the same way Jupiter did; the whole solar system could be a lot like ours,' said co-author Bruce Macintosh, from Stanford University's Kavli Institute...."
- 51 Eridani (HIP 21547)
Ashland Astronomy Studio
- "Gemini-Discovered World is Most Like Jupiter"
Gemini Observatory Press Release (August 13, 2015)
- "Astronomers discover 'young Jupiter' exoplanet"
Stanford Report, Stanford News (August 13, 2015)
(From NASA/JPL-Caltech/DSS, used w/o permission.)
("This sky map shows the location of the star HD 219134 (circle), host to the nearest confirmed rocky planet found to date outside of our solar system. The star lies just off the 'W' shape of the constellation Cassiopeia and can be seen with the naked eye in dark skies. It actually has multiple planets, none of which are habitable."
"NASA's Spitzer Confirms Closest Rocky Exoplanet"By comparing starlight that's partly blocked by an exoplanet with the star's normal light, scientists can tell how big the planet is, whether it has an atmosphere, and what the atmosphere is made of.
NASA press release (July 30, 2015)
"Using NASA's Spitzer Space Telescope, astronomers have confirmed the discovery of the nearest rocky planet outside our solar system, larger than Earth and a potential gold mine of science data.
"Dubbed HD 219134b, this exoplanet, which orbits too close to its star to sustain life, is a mere 21 light-years away. While the planet itself can't be seen directly, even by telescopes, the star it orbits is visible to the naked eye in dark skies in the Cassiopeia constellation, near the North Star.
"HD 219134b is also the closest exoplanet to Earth to be detected transiting, or crossing in front of, its star and, therefore, perfect for extensive research.
" 'Transiting exoplanets are worth their weight in gold because they can be extensively characterized,' said Michael Werner, the project scientist for the Spitzer mission at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. 'This exoplanet will be one of the most studied for decades to come.'
"The planet, initially discovered using HARPS-North instrument on the Italian 3.6-meter Galileo National Telescope in the Canary Islands, is the subject of a study accepted for publication in the journal Astronomy & Astrophysics.
"Study lead author Ati Motalebi of the Geneva Observatory in Switzerland said she believes the planet is the ideal target for NASA's James Webb Space Telescope in 2018...."
We don't know much about HD 219134b yet: but we didn't know it existed before this year. As Michael Werner said, scientists will be studying the planet for decades.
HD 219134b is close, just over 21 light-years, but it's not the closest exoplanet.
Gliese 674 b, about 14.8 light-years away, is the closest that we know of. Alpha Centauri B may — or may not — have a planet orbiting it. We don't know much about Gliese 674 b, apart from the size and shape of its orbit.
HD 219134b's year is right around 74 hours, 15 minutes, long. The planet's diameter is about 1.6 time Earth's, its mass is around 45 times our planet's: which make its density right around six grams per cubic centimeter.
That's a tad denser than our home's five and a half grams per cubic centimeter, but not by much. HD 219134b is made of pretty much the same stuff Earth is.
More about that sort of thing:
- "The Mass-Radius Relation for 65 Exoplanets Smaller Than 4 Earth Radii"
Lauren M. Weiss and Geoffrey W. Marcy, B-20 Hearst Field Annex, Astronomy Department, University of California, Berkeley, CA; ApJ Letters (January 30, 2013)
(From arxiv.org/abs/1312.0936 (May 15,2014))
The planet orbits at 0.0382 AU — 3,550,919 miles/5,714,650 kilometers — from its star, compared to Earth's 92,956,0000 miles/149,598,180 kilometers. Its star is cooler than ours: but that planet's going to be very hot.
Measuring a star's brightness only detects planets whose orbits put them between the star and Earth. How much the star dims depends on the size of the star and the transiting planet.
HD 209458, for example, dims by about 1.7% each time HD 209458 b crosses the star's disk from Earth's viewpoint.
The planet's year is a little shy of 85 hours long. HD 209458 is quite a bit like our star, but HD 209458 b is not much like Earth. It's 5,050 to 6,050 Kelvin — very roughly 5,700 Celsius or 10,300 Fahrenheit.
We know HD 209458 b's atmosphere contains carbon and oxygen, and is leaking hydrogen: astronomers can make direct spectral_observations of the planet.
Fascinating as HD 209458 b is, it almost certainly won't be the first extrasolar planet we visit. It's about 150 light-years away, and we know about many closer destinations.
More stuff you don't need to know:
- The Extrasolar Planet Encyclopaedia
- Planet HD 219134 b
The Extrasolar Planet Encyclopaedia
- "The HARPS-N Rocky Planet Search I. HD219134b: A transiting rocky planet in a multi-planet system at 6.5 pc from the Sun"
F. Motalebi, S. Udry, M. Gillon, C. Lovis, D. Segransan, L. A. Buchhave, B. O. Demory, L. Malavolta, C. D. Dressing, D. Sasselov, K. Rice, D. Charbonneau, A. Collier Cameron, D. Latham, E. Molinari, F. Pepe, L. Affer, A. S. Bonomo, R. Cosentino, X. Dumusque, P. Figueira, A. F. M. Fiorenzano, S. Gettel, A. Harutyunyan, R. D. Haywood, J. Johnson, E. Lopez, M. Lopez-Morales, M. Mayor, G. Micela, A. Mortier, V. Nascimbeni, D. Philips, G. Piotto, D. Pollacco, D. Queloz, A. Sozzetti, A. Vanderburg, C. A. Watson; abstract; Earth and Planetary Astrophysics, Cornell University Library (Submitted July 30, 2015)
Alpha Centauri Bb may or may not be the first interstellar probe's destination. The last I checked, scientists aren't sure whether the data shows a planet orbiting that stellar system's number-two star — or something else. Evidence that Alpha Centauri Bb exists is very close to HARPS' accuracy limits.
Since light from its star shines through a transiting exoplanet's atmosphere, if it has one, astronomers can make spectroscopic measurements.
It's pretty much the same as looking through a glass of water to see what's dissolved in it: only using instruments, not eyeballing it.
Fraunhofer lines are the flip side of emission spectra in sunlight. They happen because electrons release or absorb quanta in very specific ways when energy gets added or removed.
That could get me started on photons, virtual particles, quantum mechanics, wave-particle duality, and a whole mess of other stuff you don't need — or maybe want — to know.
On the other hand, maybe you're as fascinated as I am by what we're learning: which is why those links are there. I've rambled on about quantum gears and unscrewing the inscrutable before. Also phlogiston and neutrinos.
More about what we've learned so far, plus philosophizing and speculation:
- "Organics on a Comet, and Earth's Early Magnetism"
(August 7, 2015)
- "Faith, Fear, and Flying Saucers"
(August 2, 2015)
- "Pluto, Earth 2.0, and Life in the Universe"
(July 31, 2015)
- "Pluto's Unexpected Terrain; SETI, Radio, and Drums"
(July 24, 2015)
- "Harpooning the 'Rubber Duck' Comet; Public Safety — and Space Aliens"
(November 7, 2014)