Something massive, with roughly 1,000 times the area of Earth, is blocking the light coming from a distant star known as KIC 8462852, and nobody is quite sure what it is. As astronomer Tabetha Boyajian investigated this perplexing celestial object, a colleague suggested something unusual: Could it be an alien-built megastructure? Such an extraordinary idea would require extraordinary evidence. In this talk, Boyajian gives us a look at how scientists search for and test hypotheses when faced with the unknown.
Tagged with “astronomy” (40)
Wanda Diaz Merced studies the light emitted by gamma-ray bursts, the most energetic events in the universe. When she lost her sight and was left without a way to do her science, she had a revelatory insight: the light curves she could no longer see could be translated into sound. Through sonification, she regained mastery over her work, and now she’s advocating for a more inclusive scientific community. "Science is for everyone," she says. "It has to be available to everyone, because we are all natural explorers."
What first attracted one of the world’s foremost astrophysicists to the night sky? Are we alone in the universe? And how can scientific thinking benefit us all?
50th anniversary of the equation that launched the search for ET.
Kevin Fong celebrates the anniversary of one of the most iconic equations ever written. The Drake Equation was created by Frank Drake some half a century ago in a bid to answer one of the most profound questions facing science and humanity: are we alone? Its creation launched a 50 year, genuine scientific endeavour to search for ET, known as SETI: The Search for Extra Terrestrial Intelligence. Kevin visits the SETI Institute in Northern California, to meet the great man himself, Frank Drake, and some of his scientific colleagues who have spent most of their working lives hunting for signs of alien life, out there in the cosmic ether.
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Melvyn Bragg and his guests discuss comets, the ‘dirty snowballs’ of the Solar System. In the early 18th century the Astronomer Royal Sir Edmond Halley compiled a list of appearances of comets, bright objects like stars with long tails which are occasionally visible in the night sky. He concluded that many of these apparitions were in fact the same comet, which returns to our skies around every 75 years, and whose reappearance he correctly predicted. Halley’s Comet is today the best known example of a comet, a body of ice and dust which orbits the Sun. Since they contain materials from the time when the Solar System was formed, comets are regarded by scientists as frozen time capsules, with the potential to reveal important information about the early history of our planet and others.
Monica Grady Professor of Planetary and Space Sciences at the Open University
Paul Murdin Senior Fellow at the Institute of Astronomy at the University of Cambridge
Don Pollacco Professor of Astronomy at the University of Warwick
Last man on the Moon, Captain Gene Cernan, and Apollo 9 lunar module pilot Rusty Schweickart join Space Boffin Richard at Spacefest in Tucson, Arizona. Apollo 17 commander Cernan expresses his frustration about the state of the space programme and Rusty Schweickart warns of the asteroid threat to Earth. We also hear from astronomer Nick Howes, spaceblogger Emily Carney, Thomas Zurbuchen on how small satellites could be the future for big science missions and the going rates for astronaut autographs.
The darkness of dark matter and dark energy
All that we know of the universe we get from observing photons, Natarajan pointed out.
But dark matter, which makes up 90 percent of the total mass in the universe, is called dark because it neither emits nor reflects photons—and because of our ignorance of what it is!
It is conjectured to be made up of still-unidentified exotic collisionless particles which might weigh about six times more than an electron.
Though some challenge whether dark matter even exists, Natarajan is persuaded that it does because of her research on “the heaviest objects in the universe“—galaxy clusters of more than 1,000 galaxies.
First of all, the rotation of stars within galaxies does not look Keplerian—the outermost stars move far too quickly as discovered in the 1970s.
Their rapid rate of motion only makes sense if there is a vast “halo” of dark matter enclosing each galaxy.
And galaxy clusters have so much mass (90 percent of it dark) that their gravitation bends light, “lenses” it.
A galaxy perfectly aligned on the far side of a galaxy cluster appears to us—via the Hubble Space Telescope—as a set of multiple arc-shaped (distorted) galaxy images.
Studying the precise geometry of those images can reveal some of the nature of dark matter, such as that it appears to be “clumpy.”
When the next-generation of space telescopes - the James Webb Space Telescope that comes online in 2018 and the WFIRST a few years afterward, much more will be learned.
There are also instruments on Earth trying to detect dark-matter particles directly, so far without success.
As for dark energy—the accelerating expansion of the universe—its shocking discovery came from two independent teams in 1998-99.
Dark energy is now understood to constitute 72 percent of the entire contents of the universe.
(Of the remainder, dark matter is 23 percent, and atoms—the part that we know—makes up just 4.6 percent.)
But when the universe was just 380,000 years old (13.7 billion years ago), there was no dark energy.
But now “the universe is expanding at a pretty fast clip.”
Natarajan hopes to use galaxy-cluster lensing as a tool “to trace the geometry of space-time which encodes dark energy.”
These days, she said, data is coming in from the universe faster than theory can keep up with it.
”We are in a golden age of cosmology.”
Astronomer and Sky at Night TV presenter Chris Lintott tells Jim Al Khalili about his "Citizen Science" project of crowd-sourced astronomy, Galaxy Zoo, and of working with Brian May and the late Sir Patrick Moore.
Star Talk’s Neil deGrasse Tyson on how data is revolutionizing astronomy, why he hates "balance," and why his being black often leads people to confuse him for a sportscaster.
Dr. Jill Tarter holds the Bernard M. Oliver Chair for SETI Research at the SETI Institute in California. She has spent majority of her professional career attempting to determine whether we are alone in the universe, and among her other prior positions, she was the Project Scientist for NASA’s SETI program. In this interview, Dr. Tarter tells us about the latest in SETI research, including what we can expect the Square Kilometer Array to contribute to SETI.
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