MPI for Gravitational Physics/W.Benger-ZIB
This computer simulation shows the production of gravitational waves during a black hole collision.
Space Stories 2015
Every year, Discovery News turns to our faithful readers to see which space stories excited you the most and 2015 has been yet another incredible year for astronomy, spaceflight, planetary science and solar system discovery. After pulling together the nominations by considering web traffic over the past 12 months,the selection was put up for a vote
across social media and the top 10 quickly became obvious -- with a very clear winner. Can you guess which stories made it into the top 10? Read on to find out.
(Want to compare this year's top 10 with last year? Read "Top 10 Space Stories of 2014: Readers' Choice
With NASA's Dawn mission arriving at Ceres and New Horizons flying past Pluto, 2015 will forever be known as the "Year of the Dwarf Planet." But Ceres will forever be known as the dwarf planet we visited
. In March, the mission, that had made the slow transit from massive asteroid Vesta,arrived in Ceres orbit
, revealing a fascinating, pock-marked surface. A puzzle quickly presented itself -- what the heck are those bright spots? Although Dawn is orbiting the tiny world closer than ever,these bright patches still perplex scientists
, highlighting just what a mysterious and fascinating place Ceres is.PHOTOS: Ceres Delights: Dawn's Latest Dwarf Planet Views
20th Century Fox
Sure, it's a movie, but it's a movie that starred Matt Damon and co-starred SCIENCE! Not only did "The Martian" become a box office success, it was a rare movie that pleased scientists and the general public alike. There were afew scientific missteps
, but overall, it was a science fiction movie that realized that scientific accuracy can drive a great story forward without having to unnecessarily stray into scientific fantasy.
The Martian: Science vs. Fiction
Tour 'The Martian' Movie Set... On Mars
While many of the headlines focus on its younger roving cousin, Curiosity, NASA's Mars Exploration Rover Opportunity is still exploring the Red Planet despite 10 years of dusty wear and tear. The veteran robothas even completed an extraterrestrial marathon this year
, proving thatyears of steady progress
, despiterecently suffering more "amnesia" problems
, can pay off. Be sure to keep an eye on this mission, it's not done with Mars quite yet.MORE: 10 Years On Mars: Opportunity’s First Sols
The NASA/ESA Hubble Space Telescope is nothing short of a scientific and cultural phenomenon. Since 1990, the powerful space telescope has been pushing the boundaries of astronomical breakthroughs, refining our understanding of our place in the cosmos. And this year it celebrated its
quarter of a century
in space -- an incredible feat. As we look forward to the launch of NASA's James Webb Space Telescope (scheduled for 2018), we can only hope that Hubble's successor will have the longevity of the world's most famous space telescope.
Hubble at 25: The Space Telescope by the Numbers
Hubble at 25: What's Next for the Space Telescope?
Hubble at 25: Space Telescope's Top Science Discoveries
Hubble at 25: Brief History of the Hubble Space Telescope
continues to wow the world with incredible images and science from the slopes of Mount Sharp in the center of Gale Crater. The robotic geologist has not only revealed the stunning array of surface features the region has to offer, but it has also discovered potential for past habitable environments andan abundance of evidence for past liquid water flowing on Mars' surface
. It is a mission of epic proportions and has been a Reader's Choice favorite since it landed on the Red Planet in 2012 -- we can't wait to see what adventures Curiosity has in store for us in 2016.PHOTOS: Curiosity Plays in Sandy Martian Dunes
After a decade of orbiting Saturn, NASA's Cassini mission has startedits farewell tour
. Having most recently carried out its final flyby of enigmatic moon Enceladus, the spacecraft will begin maneuvers in 2016 that will ultimately see the mission fly through the planet's ring plane. Then, the spacecraftwill conclude its "Grand Finale"
, burning up in Saturn's atmosphere. 2015 has been a huge year for Cassini, revealing more incredible science about Saturn's system of moons, rings and dynamic atmosphere and we look forward to more science and beautiful images like this onebefore mission end
.MORE: Cassini's Final Flyby of Ice Moon Enceladus
This story rapidly became 2015's viral story of the year because...
Actually, it'sprobably a cloud of comets
, but the mere hint ofa possible alien megastructure orbiting a star some 1,500 light-years away
was enough to throw the internet into a spin. But the best thing about this story is that NASA's Kepler space telescope was thrown into the limelight and the stunning science of exoplanet detection became an international talking point. Since the original detection of the weird transit signal discovered by citizen scientists of the Planet Hunters project, the SETI Institute has turned its powerful Allen Telescope Array at Tabby's Starto find no transmitting aliens
. Still, it doesn't mean it's
aliens, it just means there are far more likely explanations.MORE: Has Kepler Discovered an Alien Megastructure?
Ahhh, water on Mars. Yes, we already know that there's water ICE on Mars, but this time it's different. Well, it MIGHT be different. Way back in 2011, some strange seasonal channels were spotted by NASA's Mars Reconnaissance Orbiter on Martian slopes. Though they looked like channels created by flows of liquid water, scientists urged caution -- Mars' atmosphere is so cold and thin, only short-lived water ice should exist, right? But after orbital analysis this year, the chemical residue of these channels was analyzed, revealing that these channels may well be causedby gushing liquid water
. However, this water isn't your fresh mountain spring variety --it's highly toxic water
laced with perchlorates,if it is indeed liquid water...
MORE: So Liquid Water Flows on Mars -- Now What?
Commercial access to space has been ramping-up in recent years and 2015 has seen some of the biggest advances.Orbital Sciences has bounced back
after itsAntares rocket explosion
in 2014 and, though suffering its own huge setback witha Falcon 9 rocket explosion
in June, SpaceX returned with adramatic launch and 1st stage rocket return this month
. Add these historic advances toBlue Origins own suborbital rocket return
and we have seen 12 exciting months of commercial spaceflight successes not only to resupply the space station, but also to launch satellites and refine rocket technology. Next stop Mars?Who knows
.MORE: Lesson of SpaceX Rocket Landing: Try, Try, Try Again
It's been a long wait, but in July, NASA's New Horizons mission flew through the Pluto-Charon system for itshistoric and long awaited flyby
. The spacecraft, which took nearly a decade to reach the outer solar system, is now blasting through the Kuiper Belt and mission scientists aresteering it toward a Kuiper Belt object (KBO)
for another flyby in 2019. But its Pluto flyby was just the beginning -- the spacecraft recorded so much data that it continues to beam back detailed information about the dwarf planet,its weirdly dynamic surface
, it'scrazy assortment of moons
and someperplexing mysteries along the way
. This has been a historic year; we're finally seeing Pluto up-close and in high-definition for the first time since it was discovered by American astronomer Clyde Tombaugh in 1930.PHOTOS: Dive Onto Pluto's High-Resolution Landscape
More gravitational wave discovery rumors are flying, but this time they’ve taken a specific — and, possibly, really exciting — new twist. And what’s more, we should find out whether the astrophysical rumor mill is correct or not by the end of this week; a National Science Foundation press announcement is planned for 10:30 a.m. ET on Thursday (Feb. 11), billed as an opportunity to bring together scientists from “Caltech, MIT and the LIGO Scientific Collaboration to update the scientific community on efforts to detect (gravitational waves).”
Hot on the heels of Lawrence Krauss’ tweeted rumors about a gravitational wave discovery last month, this new clue comes from a physicist who spoke with someone who saw a pre-published paper describing the historic discovery. This may sound like sketchy third-hand information, but the details discussed sound eerily specific.
“Spies who have seen the paper say they have seen gravitational waves from a binary black hole merger,” wrote theoretical physicist Clifford Burgess, of McMaster University in Hamilton, Canada, and the Perimeter Institute for Theoretical Physics in Waterloo, in an email to his faculty that was leaked to Twitter last week.
OK, so a “black hole merger”… interesting. But there’s more.
“They claim that the two detectors detected it consistent with it moving at speed c given the distance between them, and quote an equivalent 5.1 sigma detection,” he continues. “The bh masses were 36 and 29 solar masses initially and 62 at the end. Apparently the signal is spectacular and they even see the ring-down to kerr at the end.”
Burgess closes with: “Woohoo! (I hope)”
The news (like previous rumors) focuses around the powerful Laser Interferometer Gravitational-Wave Observatory (LIGO), which was upgraded in September 2015 to detect the hypothesized minuscule spacetime warping caused by gravitational waves. LIGO, which consists of 2 stations on opposite sides of the US, is finely tuned to detect the propagation of gravitational waves through our local volume of space.
From Burgess’ message we can grasp some of the physics he is describing. If (IF!) the rumors are true, the twin LIGO stations (located in Louisiana and Washington) have detected the same gravitational wave signal — with the time delay expected between the 2 stations. That signal, traveling at the speed of light (“c”), carries with it information of the phenomenon that is creating the waves. Burgess also mentions that the signal has a statistical significance of 5.1 sigma, which exceeds the criteria for the signal being real — it is therefore a solid discovery. He also points out that the paper in question will be published by the journal Nature on Feb. 11 (Thursday), coinciding with the National Science Foundation’s meeting on the same day.
Merging Black Holes?
It is predicted that any acceleration of a large mass in the cosmos will generate ripples in spacetime. For example, 2 black holes colliding would be a hotbed of gravitational wave generation. And the email describes just that: 2 black holes (of 36 and 29 times the mass of our sun) collided and merged to create a more massive black hole “weighing in” at 62 solar masses. He also hints that the gravitational wave signal reveals the resulting black hole is spinning (a "Kerr" black hole).
Although it’s absolutley right to exercise caution and a heavy dose of skepticism when confronted with rumors of a historic astrophysical discovery, we have to consider the sources that have leaked this information so far. All are prominent physics professionals. Though they’re obviously lousy at keeping big news under their hats, they can be considered to be trustworthy. However, none of these rumors are being circulated by LIGO scientists themselves, but by physicists who are working with, or have seen LIGO data or know someone who knows someone who has seen documents pertaining to the discovery.
I’ll remain skeptically excited for the time being. But my hope is that by Thursday’s NSF announcement we’ll have knowledge of the first ever directly detected gravitational waves — 100 years after Einstein first predicted their existence. Then we can look ahead and really consider what this discovery means for the future of modern astrophysics and astronomy — not only will this be evidence that gravitational waves really do exist (even though we already had pretty solid indirect evidence of their existence), we will also have a direct signal from the mother of all cosmic collisions, revealing (beyond theory) how black holes collide and grow.