Using data collected by NASA’s late-great Cassini space probe, scientists have detected traces of complex organic molecules seeping out from Enceladus’ ice-covered ocean. It’s yet another sign that this intriguing Saturnian moon has what it takes to sustain life.

If life exists elsewhere in our Solar System, chances are it’s on Enceladus. The moon features a vast, warm subterranean ocean, one sandwiched between an icy crust and a rocky core. Previous research shows this ocean contains simple organic molecules, minerals, and molecular hydrogen—an important source of chemical energy. On Earth, hydrothermal processes near volcanic vents are known to sustain complex ecosystems, raising hopes that something similar is happening on Enceladus.

New research published today in Nature suggests Enceladus’ ocean also contains complex organic molecules—yet another sign that this moon contains the basic conditions and chemical ingredients to support life. Now, this isn’t proof that life exists on this icy moon, but it does show that Enceladus’ warm, soupy ocean is capable of producing complex and dynamic molecules, and the kinds of chemical reactions required to produce and sustain microbial life.

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Source: The Discovery of Complex Organic Molecules on Saturn’s Moon Enceladus Is a Huge Deal

But the process for redefining planet was deeply flawed and widely criticized even by those who accepted the outcome. At the 2006 IAU conference, which was held in Prague, the few scientists remaining at the very end of the week-long meeting (less than 4 percent of the world’s astronomers and even a smaller percentage of the world’s planetary scientists) ratified a hastily drawn definition that contains obvious flaws. For one thing, it defines a planet as an object orbiting around our sun – thereby disqualifying the planets around other stars, ignoring the exoplanet revolution, and decreeing that essentially all the planets in the universe are not, in fact, planets.

Even within our solar system, the IAU scientists defined “planet” in a strange way, declaring that if an orbiting world has “cleared its zone,” or thrown its weight around enough to eject all other nearby objects, it is a planet. Otherwise it is not. This criterion is imprecise and leaves many borderline cases, but what’s worse is that they chose a definition that discounts the actual physical properties of a potential planet, electing instead to define “planet” in terms of the other objects that are – or are not – orbiting nearby. This leads to many bizarre and absurd conclusions. For example, it would mean that Earth was not a planet for its first 500 million years of history, because it orbited among a swarm of debris until that time, and also that if you took Earth today and moved it somewhere else, say out to the asteroid belt, it would cease being a planet.

To add insult to injury, they amended their convoluted definition with the vindictive and linguistically paradoxical statement that “a dwarf planet is not a planet.” This seemingly served no purpose but to satisfy those motivated by a desire – for whatever reason – to ensure that Pluto was “demoted” by the new definition.

By and large, astronomers ignore the new definition of “planet” every time they discuss all of the exciting discoveries of planets orbiting other stars. And those of us who actually study planets for a living also discuss dwarf planets without adding an asterisk. But it gets old having to address the misconceptions among the public who think that because Pluto was “demoted” (not exactly a neutral term) that it must be more like a lumpy little asteroid than the complex and vibrant planet it is. It is this confusion among students and the public – fostered by journalists and textbook authors who mistakenly accepted the authority of the IAU as the final word – that makes this worth addressing.

Source: Yes, Pluto is a planet – SFGate

ESA’s Gaia mission has produced the richest star catalogue to date, including high-precision measurements of nearly 1.7 billion stars and revealing previously unseen details of our home Galaxy.

A multitude of discoveries are on the horizon after this much awaited release, which is based on 22 months of charting the sky. The new data includes positions, distance indicators and motions of more than one billion stars, along with high-precision measurements of asteroids within our Solar System and stars beyond our own Milky Way Galaxy.

[…]

The new data release, which covers the period between 25 July 2014 and 23 May 2016, pins down the positions of nearly 1.7 billion stars, and with a much greater precision. For some of the brightest stars in the survey, the level of precision equates to Earth-bound observers being able to spot a Euro coin lying on the surface of the Moon.

With these accurate measurements it is possible to separate the parallax of stars – an apparent shift on the sky caused by Earth’s yearly orbit around the Sun – from their true movements through the Galaxy.

The new catalogue lists the parallax and velocity across the sky, or proper motion, for more than 1.3 billion stars. From the most accurate parallax measurements, about ten per cent of the total, astronomers can directly estimate distances to individual stars.

Source: Gaia creates richest star map of our Galaxy – and beyond / Gaia / Space Science / Our Activities / ESA

India has successfully conducted the satellite launch needed to re-construct its Indian Regional Navigation Satellite System (IRNSS).

The Indian Space Research Organisation’s Polar Satellite Launch Vehicle PSLV-C41 ascended on Thursday, April 12th. Atop the craft was a satellite designated IRNSS-1L, the last of seven satellites in India’s constellation of navigational craft.

India understands that satellite navigation services have become an assumed resource for all manner of applications, but that relying on another nation’s network is fraught with danger in the event of war or other disputes. Like Russia, China and the European Union, India has therefore decided it needs a satnav system of its own.

[…]

ndia’s already completed the network once before: in April 2016 we covered the launch of IRNSS-G, which at the time was the seventh satellite in the constellation. But just three months later, the first satellite in the fleet broke: IRNSS-1A’s atomic clocks clocked off, leaving India with insufficient satellites to deliver its hoped-for 10-metre accuracy over land.

A replacement satellite, IRNSS-1H, failed to reach its desired orbit in August 2017.

Much rejoicing has therefore followed IRNSS-1L’s success, including the following prime-ministerial Tweet.

India’s said IRNSS has only regional ambitions: its seven satellites cover India and about 1,500km beyond the nation’s borders. But that’s enough distance to help India launch missiles, like its 5,000-km-range Agni-5, deep into Pakistan, China or Russia. Don’t forget: India is a nuclear power! The nation’s suggested it might add some more sats to the service, which would likely extend its range and enhance its accuracy.

Component-makers have already started making receivers capable of linking to INRSS satellites and other similar services, so there’s a decent chance your smartphone will be able to talk to India’s satellites should you visit the region.

Source: India completes its GPS alternative, for the second time • The Register

The supermassive black hole lurking at the center of our galaxy appears to have a lot of company, according to a new study that suggests the monster is surrounded by about 10,000 other black holes.

For decades, scientists have thought that black holes should sink to the center of galaxies and accumulate there, says Chuck Hailey, an astrophysicist at Columbia University. But scientists had no proof that these exotic objects had actually gathered together in the center of the Milky Way.

“This is just kind of astonishing that you could have a prediction for such a large number of objects and not find any evidence for them,” Hailey says.

He and his colleagues recently went hunting for black holes, using observations of the galactic center made by a NASA telescope called the Chandra X-ray Observatory.

Isolated black holes are almost impossible to detect, but black holes that have a companion — an orbiting star — interact with that star in ways that allow the pair to be spotted by telltale X-ray emissions. The team searched for those signals in a region stretching about three light-years out from our galaxy’s central supermassive black hole.

“So we’re looking at the very, very, very center of our galaxy. It’s a place that’s filled with a huge amount of gas and dust, and it’s jammed with a huge number of stars,” Hailey says.

What they found there: a dozen black holes paired up with stars, according to a report in the journal Nature.

Finding so many in such a small region is significant, because until now scientists have found evidence of only about five dozen black holes throughout the entire galaxy, says Hailey, who points out that our galaxy is 100,000 light-years across. (For reference, one light-year is just under 5.88 trillion miles.)

What’s more, the very center of our galaxy surely has far more than these dozen black holes that were just detected. The researchers used what’s known about black holes to extrapolate from what they saw to what they couldn’t see. Their calculations show that there must be several hundred more black holes paired with stars in the galactic center, and about 10,000 isolated black holes.

“I think this is a really intriguing result,” says Fiona Harrison, an astrophysicist at Caltech. She cautions that there are a lot of uncertainties and the team has found just a small number of X-ray sources, “but they have the right distribution and the right characteristics to be a tracer of this otherwise completely hidden population.”

Source: Center Of The Milky Way Has Thousands Of Black Holes, Study Shows : The Two-Way : NPR

A SpaceX rocket ripped a humongous hole in Earth’s ionosphere during a launch in California last year and may have impaired GPS satellites.

The Falcon 9 rocket was blasted from Vandenberg Air Force Base on 24 August last year. It was carrying the Formosat-5, an Earth observation satellite, built by the Taiwan’s National Space Organization.

As the rocket reached supersonic speeds minutes after liftoff, it sent gigantic circular shock acoustic waves (SAWs) rippling through the atmosphere. These SAWs continued to extend outwards for about 20 minutes at a whopping speed of about 629 to 726 meters per second – equivalent between 0.021 and 0.0242 per cent of the maximum velocity of a sheep in a vacuum in Reg units.

It’s the largest rocket-induced SAW on record, according to a paper published in the Advancing Earth and Space Science journal. The plume tore a gigantic hole, approximately 900 kilometers (559 miles) in diameter stretching to 1,770,000 square kilometers (1,099,827 square miles), more than four times the total area of California.

The ionosphere is a region of the Earth’s upper atmosphere that contains a soup of particles that have been ionized from the Sun’s rays. The researchers estimate that the SAW blasted electrons away, causing the total electron content – the concentration of electrons along a one-meter squared region – to deplete by as much as 70 per cent.

The researchers reckon the fluctuations were probably pretty small and could have led to a range of errors in GPS navigation of up to a meter – not significant enough to cause major problems until the SAW dissipated.

The particularly large circular size of the shock wave was down to the way the Falcon 9 rocket flew. It had a nearly vertical trajectory, compared to most satellite launches that fly over a horizontal trajectory before the satellites are booted into orbit.

Disruptions in the ionosphere are to be expected for every rocket launch and are also detected during volcano blasts and solar flares.

“Understanding how the rocket launches affect our upper atmosphere and space environment is important as these anthropogenic space weather events are expected to increase at an enormous rate in the near future,” the paper concluded.

Source: SpaceX blasted massive plasma hole in Earth’s ionosphere • The Register

The European Space Agency has hailed the successful test of an air-breathing engine that works in space.

The engines don’t need the oxygen found in air to burn. Instead, as the ESA has explained here, the idea is to collect air, compress it, give it a charge and then squirt it out to provide thrust.

The engine has no moving parts and all that’s needed to power the engine is electricity. Spacecraft can generally harvest that from the Sun.

The concept’s been used before by the ESA’s GOCE gravity-mapping mission, but it carried 40kg of Xenon gas to provide it with thrust so it could change altitude when its orbit became low. And once it ran out of propellant … you can guess the rest.

Hence the interest in an engine that can harvest air to keep a satellite aloft and in very low orbits. Anything in such an orbit that wants to stay there will need a periodic boost, as the drag caused by the outer reaches of the atmosphere slow spacecraft and degrade their orbits.

Source: ESA builds air-breathing engine that works in space • The Register

During a press conference after liftoff, Musk said it was dicey whether the second stage would power up at all. The fuel could have frozen, the oxygen boiled off, or the avionics failed, as the rocket spent more than five hours in our planet’s high-radiation Van Allen belts before firing up.

Usually spacecraft punch through the belts as quickly as possible to minimize the risk of damage. After hours of charged particles bombarding the podule, it still worked just fine. Ish. Maybe it was performing a touching tribute to Tesla’s autopilot software.

The payload was supposed to get into an orbit around the Sun, and skim Mars. Instead, the car will whiz past the Red Planet by a much larger margin than expected and zoom off out toward the asteroid belt. T
[…]
Musk explained what went wrong with the attempted landing of the Falcon Heavy’s central core. The booster was trying to land on the floating autonomous barge Of Course I Still Love You when it suffered a “rapid, unscheduled disassembly,” to use SpaceX’s term for crashed and burned.

According to Musk, the booster had enough main fuel to make the landing, but it ran out of the triethylaluminum and triethylborane (TEA-TEB) fuel that is used to reignite the rocket engines, which are needed to control the rate of descent. Its central motor lit up, but the two other engines didn’t.

The result was that the booster came down too fast and off target. It hit the Atlantic ocean at about 300 MPH 100 metres from the barge, and disintegrated, damaging two of the sea vessel’s four thrusters, which are used to keep the ship in position.

Source: What did we say about Tesla’s self-driving tech? SpaceX Roadster skips Mars, steers to asteroids • The Register

Typical Tesla!

KAGOSHIMA – Japan successfully launched on Saturday the world’s smallest satellite-carrying rocket following a failed attempt in January last year, the nation’s space agency said.

The rocket about the size of a utility pole, measuring 10 meters in length and 50 centimeters in diameter, lifted off from the Uchinoura Space Center in Kagoshima Prefecture and delivered its payload to its intended orbit, according to the Japan Aerospace Exploration Agency.

The No. 5 vehicle of the SS-520 series carried a microsatellite weighing about 3 kilograms developed by the University of Tokyo to collect imagery of the Earth’s surface.

The launch was aimed at verifying JAXA’s technology used to launch small rockets made with commercially available components at lower cost amid growing global demand for microsatellites. The agency used components found in home electronics and smartphones for the rocket.

JAXA launched the No. 4 vehicle on Jan. 15 last year, but terminated its flight shortly after liftoff due to a communications problem. The agency found that vibrations during liftoff caused a short circuit, leading to a loss of power in the data transmitter.

For Saturday’s launch, the agency made more than 40 improvements to prevent a recurrence.

Source: Japan successfully launches world’s smallest satellite-carrying rocket | The Japan Times

The Kepler Space Telescope has found oodles of exoplants, but now astroboffins have spotted the first exoplanets outside our galaxy.

A group of astroboffins from the University of Oklahoma has become the first to demonstrate exoplanet observations in another galaxy – one that’s 3.8 billion light years away, or one-third of the distance across the observable universe.

The discovery by a team led by professor Xinyu Dai and postdoc Eduardo Guerras, found the planets’ signatures in the spectrum of a gravitationally-microlensed galaxy behind the black hole quasar RXJ 1131−1231.

Gravitational microlensing refers to the phenomenon, predicted by Einstein, that gravity can bend light, resulting in an apparent magnification if the bodies are aligned the right way (from the point of view of the observer).

As the university explains, they believe the planets range in estimated mass from about the size of the moon, through to Jupiter-sized.

Their paper, published in Astrophysical Journal Letters and available here at the arXiv pre-print service, explains that the unbound planets they saw caused “Fe Kα line energy shifts” in the spectrum of RXJ 1131−1231.

They found the line shifts in Chandra X-ray Observatory images of the quasar, and in the paper said what they observed “has never been observed in a non-lensed AGN” [active galactic nucleus – El Reg].

The paper also explains that the researchers focussed on unbounded planets – that is, planets wandering around their galaxies rather than being part of a solar system – because planets orbiting stars don’t show up separately from their hosts.

There are around 2,000 moon-to-Jupiter sized planets for each main sequence star in their observations, the researchers wrote, which equates to trillions of stars per galaxy.

Source: Exoplanets from another galaxy spotted – take that, Kepler fatigue! • The Register

Over the past week the station has been dedicated to an S-band scan looking for new targets and refreshing the frequency list, triggered by the recent launch of the mysterious ZUMA mission. This tends to be a semi-annual activity as it can eat up a lot of observing resources even with much of the data gathering automated the data reviewing is tedious.

Upon reviewing the data from January 20, 2018, I noticed a curve consistent with an satellite in High Earth Orbit (HEO) on 2275.905MHz, darn not ZUMA… This is not uncommon during these searches. So I set to work to identify the source.

A quick identity scan using ‘strf’ (sat tools rf) revealed the signal to come from 2000-017A, 26113, called IMAGE.
[…]
So what was IMAGE? I did a little Googling and discovered that it had been ‘Lost in Space’ since December 18, 2005 after just dropping off the grid suddenly. The mission was designed to image the magnetosphere, more details about that can be found in the press kit.

NASA considered the spacecraft a total loss due to a design flaw that manifested while the spacecraft was in its extended mission. The NASA failure review did however conclude that it was possible for the spacecraft to be revived by permitting a ‘Transponder SSPC reset’ after it passed through eclipse in 2007. One must assume that didn’t occur in 2007 and they gave up.
[…]
Periodically the spacecraft will enter an eclipse and NASA surmised that this may trigger it to restart and apply power back to the communications system. That appears to have happened! As you will note from the plots below the Sun angles are presently good for IMAGE and it may just stay operational for some time to come.

Source: NASA’s Long Dead ‘IMAGE’ Satellite is Alive! – Riddles in the Sky

They found that planets in the same planetary system have correlated sizes. “Each planet is more likely to be the size of its neighbor than a size drawn at random from the distribution of observed planet sizes,” the paper said. If the system contains three or more planets, the planets are also more likely to be spaced regularly. Smaller planets seem to sit closer together than larger planets, leading scientists to believe that the patterns developed early during their formation.
[…]
This is at odds with our Solar System, Weiss explained to The Register. “Unlike these exoplanetary systems, the solar system has incredible size diversity. Earth is more than twice the radius of Mercury, Neptune is four times the radius of Earth, and Jupiter is ten times the radius of Earth. Also, the terrestrial planets are very widely spaced.”

The authors suggested the complex gravitational interactions between Jupiter and Saturn are to blame. When the terrestrial planets were still forming, Jupiter and Saturn scattered the protoplanets and increased the number of collisions among them.

Source: Astroboffins say our Solar System is a dark, violent, cosmic weirdo • The Register

Bacteria found on the outside of the International Space station could be alien life, according to a cosmonaut who has visited the satellite.

Spacewalkers regularly take samples and materials from the outside of the station when they head outside for what are officially called “extravehicular activity”. Those samples are then taken down to scientists on Earth, who study them to understand the workings of the International Space Station and possibly life in space.

“Bacteria that had not been there during the launch of the ISS module were found on the swabs,” Mr Shkaplerov told TASS. “So they have flown from somewhere in space and settled on the outside hull.”

He made clear that “it seems, there is no danger​”, and that scientists are doing more work to find out what they are.

He said also that similar missions had found bacteria that could survive temperatures between -150 degrees celsius and 150. That bacteria appears to have made its way from Earth – but suggests that it can survive in the harsh environments of space.

Source: Bacteria found on International Space Station may be alien in origin, says cosmonaut | The Independent

Planetary Habitability Laboratory

At Planet, we’ve been pursuing Mission 1: to image the entire Earth’s landmass every day. I couldn’t be more excited to announce that we have achieved our founding mission.Six years ago, our team started in a garage in Cupertino. Mission 1 was the north star: we needed to build the satellites and systems, secure the launches, bring down the data to capture a daily image of the planet at high resolution, and make it easy to access for anyone. It became the heart and soul of our company and guiding light for Planeteers. Six years ago we had 7 staff. Today, Planet employs nearly 500 people in offices around the world, we have launched over 300 satellites and currently operate 200 medium and high resolution satellites. We’ve come a long way to reach this goal!

Source: Mission 1 Complete!

Our Asgardia-1 satellite was launched successfully today from the Wallops launch site in Virginia, USA.Dr Igor Ashurbeyli, Asgardia’s Head of Nation, accompanied by members of his administration personally witnessed the launch.We are delighted to announce therefore that the Asgardia space kingdom has now established its sovereign territory in space.Congratulations to all Asgardians!

Source: Asgardia – The Space Nation

Organohalogens, a class of molecules that contain at least one halogen atom bonded to carbon, are abundant on the Earth where they are mainly produced through industrial and biological processes1. Consequently, they have been proposed as biomarkers in the search for life on exoplanets2. Simple halogen hydrides have been detected in interstellar sources and in comets, but the presence and possible incorporation of more complex halogen-containing molecules such as organohalogens into planet-forming regions is uncertain3,4. Here we report the interstellar detection of two isotopologues of the organohalogen CH3Cl and put some constraints on CH3F in the gas surrounding the low-mass protostar IRAS 16293–2422, using the Atacama Large Millimeter/submillimeter Array (ALMA). We also find CH3Cl in the coma of comet 67P/Churyumov–Gerasimenko (67P/C-G) by using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument. The detections reveal an efficient pre-planetary formation pathway of organohalogens. Cometary impacts may deliver these species to young planets and should thus be included as a potential abiotical production source when interpreting future organohalogen detections in atmospheres of rocky planets.

Organohalogens are well known for their use in industry and for their detrimental effect on the ozone layer1. Some organohalogens are also produced naturally5, through different geological and biological processes. Because of their relationship to biology and industry on Earth, organohalogens have been proposed as biomarkers on other planets2,6,7. Methyl chloride (CH3Cl), the most abundant organohalogen in the Earth’s atmosphere, has both natural and synthetic production pathways. Its total production rate approaches 3 megatonnes per year, with most originating from biological processes8. Recent observations of Cl-bearing organic molecules, including methyl chloride, on Mars by the rover Curiosity, has challenged a straightforward connection between organohalides and biology; one proposed source of Cl-bearing organic molecules on Mars is meteoritic impacts9,10. This naturally raises the question of whether circumstellar and interstellar environments can produce organohalogens abiotically, and, if so, in what amounts

Source: Protostellar and cometary detections of organohalogens

ieit turns out that these co,pounds are fairly common in space and so probably don’t mean they come from alein beings, as previously thought.

FalconSAT-3 was built in 2005 and 2006 by cadets and faculty in the Space Systems Research Center at the US Air Force Academy in Colorado Springs, CO.

In amateur service the downlink is at 435.103 MHz transmitting 1W into a ¼ whip that extends from a corner of the satellite near the Lightband separation ring. The uplink is at 145.840 MHz and the receive antenna is a ¼ whip on the opposite side of the satellite near the S-band antennas. All UHF and S-band equipment on NTIA licensed frequencies has been disabled. The ARS VHF receiver is very sensitive. Modulation is 9600 bps GMSK for the uplink and downlink. The broadcast callsign is PFS3-11, and the BBS callsign is PFS3-12, Unproto APRS via PFS3-1.

The core avionics were designed and built Mark, N4TPY, and Dino, KC4YMG at SpaceQuest and have performed remarkably well for 10 years on orbit. Jim, WD0E, was the lead engineer for FalconSAT-3 at the AFA and managed the design, construction, testing and early operations of the satellite. Inquiries about current operations should be directed to AMSAT VP Operations Drew Glasbrenner, KO4MA (ko4ma@amsat.org)

Amsat Falconsat 3 page

The entire NASA image and video library is now searchable online!

NASA Image and Video Library

Source: NASA Image and Video Library

After decades of tinkering, Peter Beck and Rocket Lab are poised to bring low-cost launches to the world.

Source: At 18, He Strapped a Rocket Engine to His Bike. Now He’s Taking on SpaceX

As opposed to running a company on insane working hours and crazy project changes, this guy is launching rockets at $5m per pop, doing 500lbs. He has a launch site that allows for a huge amount of launches into many different areas. His engines are simple and actually work. It’s a great story of a space startup that looks like it actually will work.

A black hole with three billion times the mass of the Sun has been found hurtling out of its parent galaxy at 8 million kilometers per hour! What could give it that kind of incredible boost? Turns out, it’s something even more incredible: the two supermassive black holes that merged to form it in the first place.
[…]
In astronomy, you deal with a lot of ridiculously violent cosmic phenomena. Stars explode, asteroids collide, whole galaxies smash together. When you look at the math and physics, when you actually grasp the levels of power involved, it’ll make the hair on the back of your neck stand up. It’s chaos wielded on a mind-crushing scale.

And then there’s the “two supermassive black holes colliding and merging and then launching the resulting even larger billion-solar-mass black hole out of a galaxy at nearly 8 million kilometers per hour due to gravitational waves” scale of immensity.

Source: A 3 billion solar mass black hole rockets out of a galaxy at 8 million kilometers per hour. Yes, seriously.

Pluto fans are attempting to reignite a contentious astronomy debate: What is a planet?
[…]
Is Pluto a planet?

It’s not a question scientists ask in polite company.

“It’s like religion and politics,” said Kirby Runyon, a planetary scientist at Johns Hopkins University. “People get worked up over it. I’ve gotten worked up over it.”
[…]
The issue can bring conversations to a screeching halt, or turn them into shouting matches. “Sometimes,” Runyon said, “it’s just easier not to bring it up.”

But Runyon will ignore his own advice this week when he attends the annual Lunar and Planetary Science Conference in Houston. In a giant exhibit hall crowded with his colleagues, he’s attempting to reignite the debate about Pluto’s status with an audacious new definition for planet — one that includes not just Pluto, but several of its neighbors, objects in the asteroid belt, and a number of moons. By his count, 102 new planets could be added to our solar system under the new criteria.
[…]
When the IAU voted in 2006, scientists came to the conclusion that gravitational dominance is what distinguishes the eight planets from the solar system’s other spheres. From giant Jupiter to tiny Mercury, each is massive enough to make them the bullies of their orbits, absorbing, ejecting or otherwise controlling the motion of every other object that gets too close. According to the definition, planets must also orbit the sun.

Pluto, which shares its zone of the solar system with a host of other objects, was reclassified as a “dwarf planet” — a body that resembles a planet but fails to “clear its neighborhood,” in the IAU’s parlance.
[…]
But to Runyon, that distinction is less important than what dozens of solar system worlds have in common: geology.

“I’m interested in an object’s intrinsic properties,” he said. “What it is on its surface and in its interior? Whether an object is in orbit around another planet or the sun doesn’t really matter for me.”

Runyon calls his a “geophysical” definition. A planet, he says, is anything massive enough that gravity pulls it into a sphere (a characteristic called “hydrostatic equilibrium”), but not so massive that it starts to undergo nuclear fusion and become a star.
[…]
If you talk to enough scientists on either side of this debate, you’ll notice that their arguments start to echo each other. They use the same terms to criticize the definitions they don’t like: “not useful,” “too emotional,” “confusing.” Both groups want the same thing: for the public to understand and embrace the science of the solar system. But each is convinced that only their definition can achieve that goal. And each accuses the other of confusing people by prolonging the debate.

Source: A new definition would add 102 planets to our solar system — including Pluto

Give us Pluto back!