Tag: astronomy

Why Is Pluto No Longer A Planet?

In 2006, Pluto was voted out of the planetary club by members of the International Astronomical Union

But in 2006, it was relegated to the status of dwarf planet by the International Astronomical Union (IAU). So why was Pluto demoted?

Where did the controversy start?

Pluto was discovered in 1930 by US astronomer Clyde Tombaugh, who was using the Lowell Observatory in Arizona.

Textbooks were swiftly updated to list this ninth member in the club. But over subsequent decades, astronomers began to wonder whether Pluto might simply be the first of a population of small, icy bodies beyond the orbit of Neptune.

This region would become known as the Kuiper Belt, but it took until 1992 for the first “resident” to be discovered.

The candidate Kuiper Belt Object (KBO) 1992 QBI was detected by David Jewitt and colleagues using the University of Hawaii’s 2.24m telescope at Mauna Kea.




How did this change things?

Confirmation of the first KBO invigorated the existing debate. And in 2000, the Hayden Planetarium in New York became a focus for controversy when it unveiled an exhibit featuring only eight planets.

The planetarium’s director Neil deGrasse Tyson would later become a vocal figure in public discussions of Pluto’s status.

But it was discoveries of Kuiper Belt Objects with masses roughly comparable to Pluto, such as Quaoar (announced in 2002), Sedna (2003) and Eris (2005), that pushed the issue to a tipping point.

Eris, in particular, appeared to be larger than Pluto – giving rise to its informal designation as the Solar System’s “tenth planet“.

The discovery of other icy objects similar in size to Pluto forced a re-think by the IAU

Prof Mike Brown of the California Institute of Technology (Caltech), who led the team that found Eris, would later style himself as the “man who killed Pluto”, while deGrasse Tyson would later jokingly quip that he had “driven the getaway car”.

The finds spurred the International Astronomical Union to set up a committee tasked with defining just what constituted a planet, with the aim of putting a final draft proposal before members at the IAU’s 2006 General Assembly in Prague.

Under a radical early plan, the number of planets would have increased from nine to 12, seeing Pluto and its moon Charon recognised as a twin planet, and Ceres and Eris granted entry to the exclusive club. But the idea met with opposition.

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Scientists Are Tracing the Source of One of the Most Mysterious Signals in Space

Over the past decade, we’ve found out a great deal about what fast radio bursts (FRBs) are — millisecond-long blips of intense radio emissions from deep space — but their origins remain a mystery.

Now, astronomers have tracked a repeating FRB to a dwarf galaxy nearly three billion lightyears from Earth, according to a report.

The international team, which presented its work at the annual American Astronomical Society meeting last January 2018, observed that the radio beam was being contorted by a magnetic field within a cloud of ionized gas, telling us more about the conditions these bursts take place in.




The study detailing the team’s results was recently published in Nature.

We see a sort of ‘twisting’ of the radio bursts caused by an effect known as Faraday rotation,” Jason Hessels, one of the co-authors of the study from the Netherlands Institute for Radio Astronomy, told Futurism.

We hypothesize that the source of the bursts could be a neutron star in the proximity of a massive black hole that is accreting material from its surroundings, or maybe that it is a very young neutron star embedded in a nebula (a sort of cocoon around the source).

We are basically pushing forward and zooming in even further on where these fast radio bursts are coming from,” co-author Shami Chatterjee, a senior research associate from the Cornell Center for Astrophysics and Planetary Science said.

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What Makes A Star A Star?

How do you separate a true star from the stellar wannabes of the Universe? After a decade of collecting data, astronomer Trent Dupuy thinks he finally has the answer.

With so many objects known to sit in that weird middle ground between giant planets and tiny stars, scientists have struggled to boil it down to a simple answer. What Dupuy boils it down to is mass.

Mass is the single most important property of stars because it dictates how their lives will proceed,” Dupuy, from the University of Texas at Austin, explained at the American Astronomical Society’s summer meeting earlier this month.

We benefit from that here on Earth, as our Sun is in the stellar goldilocks zone – its mass is just right to sustain nuclear fusion within its core for billions of years. This has provided the conditions for life to develop and evolve on our planet.

But not everything in the galaxy is so nice and stable. More massive stars burn through their nuclear fuel quicker, dye young, and go out with a violent bang in the form of a supernova.

Less massive objects, like brown dwarfs, are like stellar runts, possessing more mass than a planet, yet not enough mass to be a fully fledged star.

Often referred to as failed stars, they’re ubiquitous throughout the Universe, but their exceedingly dim glow makes these objects difficult to study.




First proposed to exist 50 years ago, these enigmatic objects help bridge the gap between stars and planets, but it wasn’t until more recently that astronomers began to study them in great detail.

Stars like the Sun shine as a result of nuclear reactions that constantly converts the supply of hydrogen in their cores into helium.

These same reactions determine how bright a star shines – the hotter the core, the more intense the reaction and subsequently the brighter the star’s surface will be. As expected, less massive stars are dimmer due to cooler centres, which produce slower reactions.

Don’t let the name fool you – brown dwarfs aren’t always brown. These stellar wannabes are actually red when they form, then turn to black as they slowly fizzle out over trillions of years.

That’s because despite outweighing even the largest of planets, brown dwarfs have so little mass that their centres aren’t hot enough to sustain nuclear reactions.

In the 1960s, astronomers theorised that there must be a mass limit for fusion.

Previous studies of stellar evolution have suggested that the boundary between red dwarfs (the smallest stars) and brown dwarfs was around 75 Jupiter masses (or roughly 7-8 percent of the Sun).

But until now, his measurement was never directly confirmed.

Dupuy and Michael Lui of the University of Hawaii spent the past 10 years studying 31 binary pairs of brown dwarfs with the help of the most powerful telescopes on Earth – the Keck Observatory and the Canada-France-Hawaii Telescope, as well as some input from Hubble.

By analysing a decade’s worth of imagery, Dupuy and Liu have created the first large sample study of brown dwarfs masses.

According to Dupuy, an object must weigh the equivalent of 70 Jupiters in order to spark nuclear fusion and become a star, which is slightly less than previously suggested.

The duo also determined there’s a temperature cut-off, with any object cooler than 1,600 Kelvin (approximately 1,315 Celsius and 2,400 degrees Fahrenheit) classified as a brown dwarf.

The study will help astronomers better understand the conditions under which stars form and evolve – or in the case of brown dwarfs, fail.

It could also provide new insight into planetary formation as the success or failure of star formation directly impacts the star systems they could potentially produce.

The research will be published in an upcoming edition of The Astrophysical Journal Supplement, and a pre-print is available here.

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Astronomers May Have Discovered The First Moon Ever Found Outside Our Solar System

An artistic rendering of the Kepler-1625b planetary system.

A pair of astronomers believes they’ve found a moon orbiting a planet outside our Solar System — something that has never before been confirmed to exist.

Though they aren’t totally certain of their discovery yet, the find opens up the possibility that more distant moons are out there. And that could change our understanding of how the Universe is structured.

The astronomy team from Columbia University found this distant satellite, known as an exomoon, using two of NASA’s space telescopes.

They first spotted a signal from the object in data collected by the planet-hunting telescope Kepler, and then they followed up with the Hubble Space Telescope, which is in orbit around Earth.

Thanks to the observations from these two spacecraft, the team suspect this moon orbits around a Jupiter-sized planet located about 4,000 light-years from Earth. And this planet, dubbed Kepler-1625b, orbits around a star similar to our Sun.

Scientists have strongly believed for decades that moons exist outside our Solar System, but these objects have remained elusive for scientists up until now.




There have been just a couple of candidates that astronomers have speculated about in the past, but nothing has been confirmed.

That’s because moons are thought to be too small and too faint to pick up from Earth. However, this suspected exomoon, detailed today in the journal Science Advances, is particularly large, about the size of Neptune, making it one of the few targets that our telescopes can detect.

You can make the argument that this is the lowest hanging fruit,” Alex Teachey, an astronomy graduate student at Columbia University and one of the lead authors on the paper said.

“Because it is so large, in some ways, this is the first thing we should detect because it is the easiest.”

Teachey argues that finding more moons outside our Solar System will change our understanding of how planetary systems formed thousands of light-years away.

Our cosmic neighborhood is filled with moons, and they explain a lot about how our planets came to be. Exomoons could tell similar tales.

NASA’s Hubble Space Telescope.

However, none of our moons come close to the size of this one, which creates a puzzle for astronomers.

Because it is so unusual, or at least has not been anticipated largely by the community, this poses new challenges to explain it,” says Teachey. “How do you get something like this?

It was only a few decades ago — in the late 1980s and early 1990s — that astronomers confirmed the existence of planets outside our Solar System.

Since then, thousands of these distant worlds, known as exoplanets, have been confirmed by spacecraft like Kepler and other telescopes.

Perhaps the most popular way to find exoplanets is by staring at stars, waiting for them to flicker. When a planet crosses “in front” of its host star, it dims the stars’ light ever so slightly.

These dips in brightness can be used to determine how big a planet is and the kind of orbit it’s on.

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Over The Past Nineteen Years, This Man Has Dedicated His Work To The Study Of Our Solar System

Dr. Franck Marchis is a senior planetary astronomer and chair of the exoplanet group at the Carl Sagan Center of the SETI Institute and Chief Scientific Officer and Founder at Unistellar.

He began full-time work at the Institute in June 2011 after leaving a joint position with Institute and the department of astronomy at University of California, Berkeley.

Marchis moved to the United States in October 2000 shortly after getting a Ph.D. from the University of Toulouse in France that he acquired while traveling around the world for his research and for the sake of exploration.

Over the past nineteen years, he has dedicated his work to the study of our solar system, specifically the search for asteroids with moons, using mainly ground-based telescopes equipped with adaptive optics (AO).

More recently he has been also involved in the definition of new generation of AOs for 8 -10 m class telescopes and future Extremely Large Telescopes.

He has also developed algorithms to process and enhance the quality of astronomical and biological images.




He is currently the collaboration manager of the Gemini Planet Imager Exoplanet Survey, which consists in imaging and characterizing Jupiter-like exoplanets using an extreme AO system designed for the Gemini South telescope.

Today, Marchis dedicates most of his energy to instruments capable of imaging and characterizing Earth-like exoplanets by being involved in education, public outreach, technology, and scientific investigations related to those ambitious projects both in the United States and in Europe.

Marchis is also involved in startups related to astronomy so he joined Unistellar as a Chief Scientific Officer and VR2Planets as a scientific advisor in 2017.

Marchis is a member of numerous science committees including the SETI Science council, the GPI steering Committee, the TMT Science Definition Team, PLOS One editor board, the Project Blue and the PLANETS Foundation Advisory board.

He has co-authored more than 380 scientific publications, trained numerous students, and served as a science consultant and interviewee for numerous documentaries and movies in English, French, and Spanish.

The asteroid (6639) was named Marchis in honor of his discovery of the first triple-asteroid system in 2007. He has been an affiliated Astronomer at Observatoire de Paris since 2003.

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Gravitational Wave Detection Is Going Through An Even Tighter Squeeze

A team of researchers from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hannover and from the Institute for Gravitational Physics at Leibniz Universität Hannover has developed an advanced squeezed-light source for the gravitational-wave detector Virgo near Pisa.

Now, the Hannover scientists have delivered the setup, installed it, and handed it over to their Virgo colleagues.

Beginning in autumn 2018 Virgo will use the squeezed-light source to listen to Einstein’s gravitational waves together with the worldwide network of detectors with higher sensitivity than ever before.

The German-British gravitational-wave detector GEO600 near Hannover has been routinely using a squeezed-light source since 2010.

“It has increased the part of the Universe that GEO600 listens to by a factor of up to four,” says Prof. Karsten Danzmann, director at the AEI Hannover and director of the Institute for Gravitational Physics at Leibniz Universität Hannover.

“The development and perfection of the cutting-edge technology is another successful chapter in the history of GEO600 as think thank of gravitational-wave research.”




Both US LIGO instruments and the Virgo detector based in Tuscany are currently being upgraded and improved in preparation of the next joint observation run “O3” which is planned to commence in autumn 2018.

O3 is expected to usher in full-scale gravitational-wave astronomy through a large number of further gravitational-wave detections from merging binary black holes and additional signals from merging neutron star pairs.

For this purpose, Virgo has now received a valuable addition from Hannover: A setup called a squeezed-light source is expected to significantly increase Virgo’s sensitivity from the beginning of O3.

The custom-made device is a permanent loan of the AEI to Virgo and is worth about 400,000 Euros.

The sensitivity of all interferometric gravitational-wave detectors (LIGO, Virgo, and GEO600) to the ripples of space-time from large cosmic events is fundamentally limited by quantum mechanical effects.

They cause a background noise which overlaps with the gravitational-wave signal that is measured with laser light.

The sensitivity of all interferometric gravitational-wave detectors can only be further increased in the future through the use of similar squeezed-light sources.

Planned third-generation detectors like the Einstein Telescope will also depend on this technology.

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Mars Is Spectacular This Month – Here’s The Best Way To Spy The Red Planet

If you look at the sky tonight and spot a very bright star, it may well be a planet. Mars is the closest it has been to Earth for 15 years – and therefore the brightest.

Mars shines through reflected light,” says Robert Massey, the deputy executive director of the Royal Astronomical Society.

That means that when it’s closer to the Earth it appears brighter, because its apparent size is bigger.” It won’t be this visible again until 2035.

So, how best to see it? First, make sure tall trees or buildings are not obscuring the view. Ideally, you want a clear horizon. Then, look south.




It will be obvious, because it’s bright, it doesn’t twinkle and it has a distinct reddish tinge,” says Massey, who suggests Somerset, Devon and Dorset as good locations for spotting it.

The best Mars-gazing time is 1am, but it rises earlier in the evening.

You can see Mars with the naked eye, but a pair of binoculars would help,” says Massey. “If you have a small telescope, you may be lucky to see a polar ice cap.

If you are an amateur with good equipment, the details to look out for are two polar ice caps, mountains or volcanoes, and sunken, crater-like features. Massey suggests contacting your local astronomical society about public viewing events.

Hubble’s views of Mars at two recent oppositions

When is the best time to see Mars?

According to NASA, Mars Opposition begins Friday, July 27 around midnight.

Mars will be visible between Friday, July 27 and Monday, July 30, making its closest approach — 35.8 million miles to be exact — on Tuesday, July 31 at around 4 a.m. E.T.

Mars will be at its brightest Friday night due to an opposition surge that is affected by the planet’s angle of the sun — giving you the clearest view of the Red Planet.

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Signs Of Life On Europa May Be Just Beneath The Surface

If signs of life exist on Jupiter’s icy moon Europa, they might not be as hard to find as scientists had thought, a new study reports.

The 1,900-mile-wide (3,100 kilometers) Europa harbors a huge ocean beneath its icy shell.

What’s more, astronomers think this water is in contact with the moon’s rocky core, making a variety of complex and intriguing chemical reactions possible.

Researchers therefore regard Europa as one of the solar system’s best bets to harbor alien life.

Europa is also a geologically active world, so samples of the buried ocean may routinely make it to the surface—via localized upwelling of the ocean itself, for example, and/or through geyser-like outgassing, evidence of which has been spotted multiple times by NASA’s Hubble Space Telescope.

NASA aims to hunt for such samples in the not-too-distant future. The agency is developing a flyby mission called Europa Clipper, which is scheduled to launch in the early 2020s.

Clipper will study Europa up close during dozens of flybys, some of which might be able to zoom through the moon’s suspected water-vapor plumes.

And NASA is also working on a possible post-Clipper lander mission that would search for evidence of life at or near the Europan surface.




 

It’s unclear, however, just how deep a Europa lander would need to dig to have a chance of finding anything.

That’s because Europa orbits within Jupiter’s radiation belts and is bombarded by fast-moving charged particles, which can turn amino acids and other possible biosignatures into mush.

That’s where the new study comes in.

NASA scientist Tom Nordheim and his colleagues modeled Europa’s radiation environment in detail, laying out just how bad things get from place to place.

They then combined these results with data from laboratory experiments documenting how quickly various radiation doses carve up amino acids (a stand-in here for complex biomolecules in general).

The researchers found significant variation, with some Europan locales (equatorial regions) getting about 10 times the radiation pounding of others (middle and high latitudes).

At the most benign spots, the team determined, a lander would likely have to dig just 0.4 inches (1 centimeter) or so into the ice to find recognizable amino acids.

In the high-blast zones, the target depth would be on the order of 4 to 8 inches (10 to 20 cm).

That latter range is still quite manageable, said Nordheim, who’s based at the California Institute of Technology and NASA’s Jet Propulsion Laboratory, both of which are in Pasadena.

That’s good news for the potential lander mission, Nordheim added: With radiation exposure seemingly not a limiting factor, planners can feel free to target the areas of Europa most likely to harbor fresh ocean deposits—the fallout zone beneath a plume, for example—wherever they may lie.

Scientists still haven’t identified any such promising touchdown areas; the Europa imagery captured to date just hasn’t been sharp enough. But Europa Clipper’s work should change things, Nordheim said.

When we get the Clipper reconnaissance, the high-resolution images—it’s just going to be a completely different picture,” he said. “That Clipper reconnaissance is really key.”

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Puzzling Cosmic Glow Is Caused by Diamond Dust Glamming Up Stars

Diamond dust is responsible for a mysterious glow emanating from certain regions of the Milky Way galaxy, a new study reports.

Astronomers have long known that some type of very small, rapidly spinning particle is throwing off this faint light, which is known as anomalous microwave emission (AME). But they couldn’t identify the exact culprit — until now.

In the new study, researchers used the Green Bank Telescope in West Virginia and the Australia Telescope Compact Array to search for AME light in 14 newborn star systems across the Milky Way.

They spotted the emissions in three of these systems, coming from the planet-forming disks of dust and gas swirling around the stars.

This is the first clear detection of anomalous microwave emission coming from protoplanetary disks,” study co-author David Frayer, an astronomer with the Green Bank Observatory, said in a statement.




The study team also detected the unique infrared-light signatures of nanodiamonds — carbon crystals far smaller than a grain of sand — in these same three systems, and nowhere else.

In fact, these [signatures] are so rare, no other young stars have the confirmed infrared imprint,” study lead author Jane Greaves, an astronomer at Cardiff University in Wales, said in the same statement.

The researchers don’t think this is a coincidence.

One to 2 percent of the total carbon in these protoplanetary disks has been incorporated into nanodiamonds, according to the team’s estimates.

Another leading AME-source candidate, a family of organic molecules known as polycyclic aromatic hydrocarbons (PAHs), doesn’t hold up under scrutiny, the researchers said.

The infrared signature of PAHs has been identified in multiple young star systems that lack an AME glow, they noted.

The new results could help astronomers better understand the universe’s early days, study team members said.

Scientists think the universe expanded far faster than the speed of light shortly after the Big Bang, in a brief period of “cosmic inflation.

If this did indeed happen, it should have left a potentially detectable imprint — an odd polarization of the cosmic microwave background, the ancient light left over from the Big Bang.

The new study provides “good news for those who study polarization of the cosmic microwave background, since the signal from spinning nanodiamonds would be weakly polarized at best,” said co-author Brian Mason, an astronomer at the National Radio Astronomy Observatory in Charlottesville, Virgina.

This means that astronomers can now make better models of the foreground microwave light from our galaxy, which must be removed to study the distant afterglow of the Big Bang,” Mason added.

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Saturn Found To Have Noontime Auroras

An international team of researchers has found that Saturn’s fast rotation speed makes it possible for the planet to experience noontime auroras.

In their paper published in the journal Nature Astronomy, the group describes the factors that lead to creation of auroras and how Saturn’s appear to arise.

Auroras on Earth occur when magnetic reconnections (magnetic fields colliding) cause solar flares on the sun. When it happens, plasma carrying a magnetic field is shot out into space, some of which makes its way to Earth.

When it collides with our planet’s magnetic field, auroras occur. The same process has been observed on Venus, Mars, Jupiter, Saturn and Uranus.

In this new effort, the researchers were studying data sent back from the Cassini spacecraft, which orbited Saturn for 13 years.




They were looking specifically at data that would provide more information regarding magnetic reconnections on the planet—prior research had shown that they occur on the dayside of the magnetopause (the point where the planet’s magnetic field meets the solar wind).

There was also evidence that they occur on the nightside of its magnetodisk, which is a plasma ring formed near the equator by water and other materials emitted from its moons.

But prior research had also suggested that there would be no reconnections on the dayside of the planet’s magnetodisk because the solar winds made the to too thick for them to occur.

But the researchers found evidence of reconnections in the magnetodisk at noontime anyway. The researchers suggest this apparent anomaly is likely due to Saturn’s high spin rate (a day is just 10 hours).

The high rate, they note, likely compresses the magnetodisk, making it thin enough for reconnections to occur. The team also suggests that the reconnections they measured appear to be strong enough to create auroras.

The researchers suggest that their findings indicate that unknown auroras might be happening on other planets as well, but have been overlooked because planet spin speed was not factored into calculations.

They further suggest that similar reconnections might also be behind some unexplained pulses seen from Jupiter.

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