Newest Planet: Is it Pluto, Eris or Extrasolar?

Eris, the newest planet?
Eris, the newest planet?

With astronomers discovering new planets and other celestial objects all the time, you may be wondering what the newest planet to be discovered is. Well, that depends on your frame of reference. If we are talking about our Solar System, then the answer used to be Pluto, which was discovered by the American astronomer Clyde William Tombaugh in 1930.

Unfortunately, Pluto lost its status as a planet in 2006 when it was reclassified as a dwarf planet. Since then, another contender has emerged for the title of “newest planet in the Solar System” – a celestial body that goes by the name of Eris – while beyond our Solar System, thousands of new planets are being discovered.

But then, the newest planet might be the most recently discovered extrasolar planet. And these are being discovered all the time.

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What is the Habitable Zone?

What is the Habitable Zone?

We’ve found hundreds of exoplanets in the galaxy. But only a few of them have just the right combination of factors to hold life like Earth’s.


The weather in your hometown is downright uninhabitable. There’s scorching heatwaves, annual tyhpoonic deluges, and snow deep enough to bury a corn silo.

The bad news is planet Earth is the only habitable place we know of in the entire Universe. Also, are the Niburians suffering from Niburian made climate change? Only Niburian Al Gore can answer that question.

We as a species are interested in habitability for an assortment of reasons, political, financial, humanitarian and scientific. We want to understand how our own climate is changing. How we’ll live in the climate of the future and what we can do to stem the tide of what our carbon consumption causes.

There could be agendas to push for cleaner energy sources, or driving politicians towards climate change denial to maintain nefarious financial gain.

We also might need a new lilypad to jump to, assuming we can sort out the travel obstacles. The thing that interests me personally the most is, when can I see an alien?

The habitable zone, also known as the “Goldilocks Zone”, is the region around a star where the average temperature on a planet allows for liquid water with which to make porridge. It’s that liquid water that we hunt for not only for our future uses, but as an indicator of where alien life could be in the Universe.

Problems outside this range are pretty obvious. Too hot, it’s a perpetual steam bath, or it produces separate piles of hydrogen and oxygen. Then your oxygen combines with carbon to form carbon dioxide, and then hydrogen just buggers off into space.

This is what happened with Venus. If the planet’s too cold, then bodies of water are solid skating rinks. There could be pockets of liquid water deep beneath the icy surface, but overall, they’re bad places to live.

We’ve got this on Mars and the moons of Jupiter and Saturn. The habitable zone is a rough measurement. It’s a place where liquid water might exist.

"The Chemistry of the Solar System" by Compound Interest's Andy Brunning
“The Chemistry of the Solar System” by Compound Interest’s Andy Brunning

Unfortunately, it’s not just a simple equation of the distance to the star versus the amount of energy output. The atmosphere of the planet matters a lot. In fact, both Venus and Mars are considered to be within the Solar System’s habitable zone.

Venusian atmosphere is so thick with carbon dioxide that it traps energy from the Sun and creates an inhospitable oven of heat that would quickboil any life faster than you can say “pass the garlic butter”.

It’s the opposite on Mars. The thin atmosphere won’t trap any heat at all, so the planet is bun-chillingly cold. Upgrade the atmospheres of either planet and you could get worlds which would be perfectly reasonable to live on. Maybe if we could bash them together and we could spill the atmosphere of one onto the other? Tell Blackbolt to ring up Franklin Richards, I have an idea!

When we look at other worlds in the Milky Way and wonder if they have life, it’s not enough to just check to see if they’re in the habitable zone. We need to know what shape their atmosphere is in.

Astronomers have actually discovered planets located in the habitable zones around other stars, but from what we can tell, they’re probably not places you’d want to live. They’re all orbiting red dwarf stars.

Goldilocks Zone
Artists impression of Gliese 581g. Credit: Lynette Cook/NSF

It doesn’t sound too bad to live in a red tinted landscape, provided it came with an Angelo Badalamenti soundtrack, red dwarf stars are extremely violent in their youth. They blast out enormous solar flares and coronal mass ejections. These would scour the surface of any planets caught orbiting them close enough for liquid water to be present.

There is some hope. After a few hundred million years of high activity, these red dwarf stars settle down and sip away at their fuel reserves of hydrogen for potentially trillions of years. If life can hold on long enough to get through the early stages, it might have a long existence ahead of it.

When you’re thinking about a new home among the stars, or trying to seek out new life in the Universe, look for planets in the habitable zone.

As we’ve seen, it’s only a rough guideline. You probably want to check out the place first and make sure it’s truly liveable before you commit to a timeshare condo around Gliese 581.

Do you think habitable planets are common in the Milky Way? Tell us what your perfect planet environment might be in the comments below.

Weekly Space Hangout – June 12, 2015: Astronomy in Chile Educator Ambassadors Program

Host: Fraser Cain (@fcain)

Special Guest: This week we welcome Astronomy in Chile Educator Ambassadors Program Participants:
Michael Prokosch (Seeing Stars Blog, MikeProkosch@shsuobservatory)
Tim Spuck ([email protected])
Brian Koberlein (@briankoberlein / briankoberlein.com)
Vivian White ([email protected]).

Guests:
Jolene Creighton (@jolene723 / fromquarkstoquasars.com)
Brian Koberlein (@briankoberlein / briankoberlein.com)
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Alessondra Springmann (@sondy)
Continue reading “Weekly Space Hangout – June 12, 2015: Astronomy in Chile Educator Ambassadors Program”

Weekly Space Hangout – June 5, 2015: Stephen Fowler, Creative Director at InfoAge

Host: Fraser Cain (@fcain)
Special Guest: This week we welcome Stephen Fowler, who is the Creative Director at InfoAge, the organization behind refurbishing the TIROS 1 dish and the Science History Learning Center and Museum at Camp Evans, Wall, NJ.

Guests:
Jolene Creighton (@jolene723 / fromquarkstoquasars.com)
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )

Continue reading “Weekly Space Hangout – June 5, 2015: Stephen Fowler, Creative Director at InfoAge”

Weekly Space Hangout – May 29, 2015: Dr. Bradley M. Peterson

Host: Fraser Cain (@fcain)
Special Guest: This week we welcome Dr. Bradley M. Peterson, whose research is directed towards determination of the physical nature of active galactic nuclei.
Guests:
Jolene Creighton (@jolene723 / fromquarkstoquasars.com)
Charles Black (@charlesblack / sen.com/charles-black)
Brian Koberlein (@briankoberlein / briankoberlein.com)
Dave Dickinson (@astroguyz / www.astroguyz.com)
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Alessondra Springmann (@sondy)
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Why Don’t We Search for Different Life?

Why Don’t We Search for Different Life?

If we really want to find life on other worlds, why do we keep looking for life based on carbon and water? Why don’t we look for the stuff that’s really different?

In the immortal words of Arthur C. Clarke, “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.”

I’m seeking venture capital for a Universal buffet chain, and I wondering if I need to include whatever the tentacle equivalent of forks is on my operating budget. If there isn’t any life, I’m going to need to stop watching so much science fiction and get on with helping humanity colonize space.

Currently, astrobiologists are hard at work searching for life, trying to answer this question. The SETI Institute is scanning radio signals from space, hoping to catch a message. Since humans use radio waves, maybe aliens will too. NASA is using the Curiosity Rover to search for evidence that liquid water existed on the surface of Mars long enough for life to get going. The general rule is if we find liquid water on Earth, we find life. Astronomers are preparing to study the atmospheres of extrasolar planets, looking for gasses that match what we have here on Earth.

Isn’t this just intellectually lazy? Do our scientists lack imagination? Aren’t they all supposed to watch Star Trek How do we know that life is going to look anything like the life we have on Earth? Oh, the hubris!

Who’s to say aliens will bother to communicate with radio waves, and will transcend this quaint transmission system and use beams of neutrinos instead. Or physics we haven’t even discovered yet? Perhaps they talk using microwaves and you can tell what the aliens are saying by how your face gets warmed up. And how do we know that life needs to depend on water and carbon? Why not silicon-based lifeforms, or beings which are pure energy? What about aliens that breathe pure molten boron and excrete seahorse dreams? Why don’t these scientists expand their search to include life as we don’t know it? Why are they so closed-minded?

Viking Lander
In 1976, two Viking spacecraft landed on Mars. The image is of a model of the Viking lander, along with astronomer and pioneering astrobiologist Carl Sagan. Each lander was equipped with life detection experiments designed to detect life based on its metabolic activities.
Credits: NASA/Jet Propulsion Laboratory, Caltech

The reality is they’re just being careful. A question this important requires good evidence. Consider the search for life on Mars. Back in the 1970s, the Viking Lander carried an experiment that would expose Martian soil to water and nutrients, and then try to detect out-gassing from microbes. The result of the experiment was inconclusive, and scientists still argue over the results today. If you’re going to answer a question like this, you want to be conclusive. Also, getting to Mars is pretty challenging to begin with. You probably don’t want to “half-axe” your science.

The current search for life is incremental and exhaustive. NASA’s Spirit and Opportunity searched for evidence that liquid water once existed on the surface of Mars. They found evidence of ancient water many times, in different locations. The fact that water once existed on the surface of Mars is established. Curiosity has extended this line of research, looking for evidence that water existed on the surface of Mars for long periods of time. Long enough that life could have thrived. Once again, the rover has turned up the evidence that scientists were hoping to see. Mars was once hospitable for life, for long periods of time. The next batch of missions will actually search for life, both on the surface of Mars and bringing back samples to Earth so we can study them here.

The search for life is slow and laborious because that’s how science works. You start with the assumption that since water is necessary for life on Earth, it makes sense to just check other water in the Solar System. It’s the low hanging fruit, then once you’ve exhausted all the easy options, you get really creative.

An illustration of a Titanic lake by Ron Miller. All rights reserved. Used with permission.
An illustration of a Titanic lake by Ron Miller. All rights reserved. Used with permission.

Scientists have gotten really creative about how and where they could search for life. Astrobiologists have considered other liquids that could be conducive for life. Instead of water, it’s possible that alternative forms of life could use liquid methane or ammonia as a solvent for its biological processes. In fact, this environment exists on the surface of Titan. But even if we did send a rover to Titan, how would we even know what to look for?

We understand how life works here, so we know what kinds of evidence to pursue. But kind of what evidence would be required to convince you there’s life as you don’t understand it? Really compelling evidence.
Go ahead and propose some alternative forms of life and how you think we’d go searching for it in the comments.

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Everything About Kepler-432b is Extreme, Especially the Way it’s Going to Die

Illustration of the orbit of Kepler-432b (inner, red) in comparison to the orbit of Mercury around the Sun (outer, orange). Credit: Dr. Sabine Reffert.

Astronomers are calling Kepler-432b a ‘maverick’ planet because everything about this newly found exoplanet is an extreme, and is unlike anything we’ve found before. This is a giant, dense planet orbiting a red giant star, and the planet has enormous temperature swings throughout its year. In addition to all these extremes, there’s another reason you wouldn’t want to live on Kepler 432b: its days are numbered.

“In less than 200 million years, Kepler-432b will be swallowed by its continually expanding host star,” said Mauricio Ortiz, a PhD student at Heidelberg University who led one of the two studies of the planet. “This might be the reason why we do not find other planets like Kepler-432b – astronomically speaking, their lives are extremely short.”

Kepler-432b is one of the densest and massive planets ever found. The planet has six times the mass of Jupiter, but is about the same size. The shape and the size of its orbit are also unusual, as the orbit is very small (52 Earth days) and highly elongated. The elliptical orbit brings Kepler-432b both incredibly close and very far away from its host star.

“During the winter season, the temperature on Kepler-432b is roughly 500 degrees Celsius,” said Dr. Sabine Reffert from the Königstuhl observatory, which is part of the Centre for Astronomy. “In the short summer season, it can increase to nearly 1,000 degrees Celsius.”

Dr. Davide Gandolfi, also from the Königstuhl observatory, said that the star Kepler-432b is orbiting has already exhausted the nuclear fuel in its core and is gradually expanding. Its radius is already four times that of our Sun and it will get even larger in the future.

While Kepler-432b was previously identified as a transiting planet candidate by the NASA Kepler satellite mission, two research groups of Heidelberg astronomers independently made further observations of this rare planet, acquiring the high-precision measurements needed to determine the planet’s mass. Both groups of researchers used the 2.2-metre telescope at Calar Alto Observatory in Andalucía, Spain to collect data. The group from the state observatory also observed Kepler-432b with the Nordic Optical Telescope on La Palma (Canary Islands).

The results of this research were published in Astronomy & Astrophysics.

Source: University of Heidelberg

250 Years of Planetary Detection in 60 Seconds

An animated history of planetary detection, from 1750 to 2015. It shows the period (x-axis), mass (y-axis), radius (circle size) and detection method (color) of the 1800 plus planets now known. Credit and copyright: Hugh Osborn.

Early astronomers realized some of the “stars” in the sky were planets in our Solar System, and really, only then did we realize Earth is a planet too. Now, we’re finding planets around other stars, and thanks to the Kepler Space Telescope, we’re able to find planets that are even smaller than Earth.

This great new graphic of the history of planetary detection was put together by Hugh Osborn, a PhD student at the University of Warwick, who works with data from the WASP (Wide Angle Search for Planets) and NGTS (Next Generation Transit Survey) telescope surveys to discover exoplanets. It starts with the first real “discovery’ of a planet — Uranus in 1781 by William and Caroline Herschel.

“The idea of this plot is to compare our own Solar System (with planets plotted in dark blue) against the newly-discovered extrasolar worlds,” wrote Osborn on his website. “Think of this plot as a projection of all 1873 worlds onto our own solar system, with the Sun (and all other stars) at the far left. As you move out to the right, the orbital period of the planets increases, and correspondingly (thanks to Kepler’s Third Law), so does the distance from the star. Moving upwards means the mass of the worlds increase, from Moon-sized at the base to 10,000 times that of Earth at the top (30 Jupiter Masses).”

You’ll notice a few “clusters” as time moves along. The circles in dark blue are the planets in our Solar System; light blue are planets found by radial velocity. Then in maroon are planets found by direct imaging, followed by orange for microlensing and green for transits.

The first batch of exoplanets were the massive ‘Hot Jupiters’, which were the first exoplanets found “simply because they are easiest to find,” using the radial velocity method. Then you’ll see clusters found by the other methods ending with the big batch found by Kepler.

“This clustering shows that there are more Earth and super-Earth sized planets than any other,” said Osborn. “Hopefully we can begin to probe below it’s limit and into the Earth-like regime, where thousands more worlds should await!”

On reddit, Osborn also provided great, short explanations of the various methods used to detect planets, which we’ll include below:

Radial Velocity

Planets orbit thanks to gravitational attraction from their star’s mass. But the mass of the planet also has an effect on the star – pulling it around in a tiny circle once every orbit. Astronomers can split the light from a star up into it’s colours, which have an atomic barcode of absorption lines in. These lines shift position as the star moves – the light is effectively compressed to bluer colours when moving towards and pulled to redder colours when moving away.

So, by measuring this to-and-fro (radial) velocity, and finding periodic signals, astronomers can detect the tug of distant exoplanets.

Direct Imaging

This is easier to get your head around – point a big telescope at a star and directly image a planet around it. This only work for the biggest young planets as these are warmest, so glow brightest in the infra-red (like a red-hot piece of Iron). To find the planet in the glare of it’s star, the starlight needs to be suppressed. This is done by either blocking it out with a starshade, or digitally combining the images in such a way to remove the central star, revealing new exoplanets.

Microlensing

Einstein’s general theory of relativity shows that mass bends space time. This means that light can be bent by massive objects, and even act like a lens. Occasionally a star with a planetary system passes in front of a distant star. The light from the distant star is bent and lensed by both the star and the planet, giving two sharp increases in brightness over a few days – one for the star and one for the planet. The amount of lensing gives the mass of the planets, and the time between the events gives us the distance from their star. More info

Transits

When a planet crosses in front of it’s star, it blocks out a small portion of sunlight depending on it’s size. We only see the star as a single point, but we can infer the presence of a planet from the dip in light. When this repeats, we get a period. This is how we have found more than 1000 of the current crop of ~1800 exoplanets!

Thanks to Hugh Osborn for sharing his expertise with Universe Today!

Astronomy Cast Ep. 367: Spitzer does Exoplanets

We’ve spent the last few weeks talking about different ways astronomers are searching for exoplanets. But now we reach the most exciting part of this story: actually imaging these planets directly. Today we’re going to talk about the work NASA’s Spitzer Space Telescope has done viewing the atmospheres of distant planets.
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Oldest Planetary System Discovered, Improving the Chances for Intelligent Life Everywhere

An artist rendition of Kepler-444 planetary system, which hosts five planets, all smaller than Earth. Credit: Tiago Campante, University of Birmingham, UK.

Using data from the Kepler space telescope, an international group of astronomers has discovered the oldest known planetary system in the galaxy – an 11 billion-year-old system of five rocky planets that are all smaller than Earth. The team says this discovery suggests that Earth-size planets have formed throughout most of the Universe’s 13.8-billion-year history, increasing the possibility for the existence of ancient life – and potentially advanced intelligent life — in our galaxy.

“The fact that rocky planets were already forming in the galaxy 11 billion years ago suggests that habitable Earth-like planets have probably been around for a very long time, much longer than the age of our Solar System,” said Dr. Travis Metcalfe, Senior Research Scientist Space Science Institute, who was part of the team that used the unique method of asteroseismology to determine the age of the star.

The star, named Kepler-444, is about 25 percent smaller than our Sun and is 117 light-years from Earth. The system of five known planets is very compact, and all five planets orbit the parent star in less than 10 days, or within 0:08 AU, roughly one-fifth the size of Mercury’s orbit.

“The star is slightly cooler than the Sun (around 5000 K at the surface, compared to 5800 K),” Metcalfe told Universe Today, “but the planets in this system are still expected to be highly irradiated and inhospitable to life,” with little to no atmospheres.

The team wrote in their paper that the system’s habitable zone lies 0:47 AU from the parent star and so all planets orbit well interior to the inner edge of Kepler-444’s ‘Goldilocks zone.’

The team was led by Tiago Campante, a research fellow at the University of Birmingham in the UK.

The planets were found by analyzing four years of Kepler data, as the spacecraft had nearly continuous observations of Kepler-444 during Kepler’s active mission. The space telescope took high-precision measurements of changes in brightness in stars in its field of view. There are tiny changes in brightness when planets pass in front of their stars.

Transit signals indicated five planets orbiting Kepler-444, although this star has a binary companion, an M-dwarf, and it was a tedious process to tease out all the data to determine what were planets and not other stars, as well as which star the planets were orbiting.

An image of the Kepler-444 star system using the NIRC2 near-infrared imager on the Keck II telescope. Credit: Tiago Campante et al.
An image of the Kepler-444 star system using the NIRC2 near-infrared imager on the Keck II telescope. Credit: Tiago Campante et al.

Metcalfe said the the job of “validating” the planets by ruling out all of the other possible “false positive” scenarios is always a big challenge for Kepler targets.

But asteroseismology was used to directly measure the precise age of the star. Asteroseismology, or stellar seismology is basically listening to a star by measuring sound waves. The sound waves travel into the star and bring information back up to the surface. The waves cause oscillations that Kepler observes as a rapid flickering of the star’s brightness.

How can this help determine a star’s age?

“As a star ages, it converts hydrogen into helium in the core,” Metcalfe said via email. “This changes the mean density of the star over time, and asteroseismology provides a very precise measure of the mean density (from the regular spacing of the individual oscillation frequencies).”

Metcalfe said that in this case, the uncertainty on the age of the star (and thus the planets, which formed essentially at the same time) is only 9%, compared to a typical uncertainty of 30-50% from other methods based on rotation (gyrochronology) or other properties of the star.

The team also noted in their paper that this finding may also help to pinpoint the beginning of the era of planet formation.

“I think this system has a lot to teach us about planet formation and the long-term evolution of planetary systems,” said Darin Ragozzine, a professor at Florida Institute of Technology and a a member of the discovery team, who specializes in multi-transiting systems. “With an age of 11.2 billion years, it means that this system formed near the beginning of the age of the Universe.”

The team wrote that this finding implies that small, Earth-size, planets may have readily formed at early epochs in the Universe’s history, even when metals were more scarce.

“By the time Earth formed, this star and its planetary system were already older than our planet is today,” Ragozzine told Universe Today. “We don’t know for sure if this system has stayed the same the whole time, but it is amazing to think that the little inner planet has gone around the star about a trillion times!”

To find out more about asteroseismology, check out a website called the Pale Blue Dot Project. Metcalfe launched a non-profit organization to help raise research funds for the Kepler Asteroseismic Science Consortium. The Pale Blue Dot Project allows people to adopt a star to support asteroseismology, since there is no NASA funding for asteroseismology.

“Much of the expertise for this exists in Europe and not in the US, so as a cost saving measure NASA outsourced this particular research for the Kepler mission,” said Metcalfe, “and NASA can’t fund researchers in other countries.”

Metcalfe added that the “adopt a star” program supported the asteroseismic analysis of Kepler-444, “determining the precise age that makes this ancient planetary system so interesting… This private funding from citizens around the world has been an invaluable resource to facilitate our research and fuel amazing discoveries like this one.”

You can help this research by adopting one of the Kepler stars or planetary systems.

This research was published today in the Astrophysical Journal.

The team’s paper is titled, “An Ancient Extrasolar System with Five Sub-Earth-Size Planets.”