Astronomy Archives

February 22, 2019February 22, 2019 by Paul M. Sutter

Meet WFIRST, The Space Telescope with the Power of 100 Hubbles

The Wide First Infrared Telescope (so far). Image credit: NASA/TJT Photography

WFIRST ain’t your grandma’s space telescope. Despite having the same size mirror as the surprisingly reliable Hubble Space Telescope, clocking in at 2.4 meters across, this puppy will pack a punch with a gigantic 300 megapixel camera, enabling it to snap a single image with an area a hundred times greater than the Hubble.

With that fantastic camera and the addition of one of the most sensitive coronagraphs ever made – letting it block out distant starlight on a star-by-star basis – this next-generation telescope will uncover some of the deepest mysteries of the cosmos.

Oh, and also find about a million exoplanets.

January 31, 2019January 31, 2019 by David Dickinson

When Does the Sun Rise… Really?

Mercury Sunrise — A transit of Mercury at sunrise. Image credit and copyright: Alan Dyer.

It’s strange but true. We may not fully understand one of the simplest metrics in observational astronomy: just what time does the Sun rise… really?

January 3, 2019January 3, 2019 by Evan Gough

See a Simulation of the Moon for Every Day in 2019

NASA's Visualization Studio has released its yearly moon simulation viewer. Image: NASA

It’s always easier to show someone a picture of something rather than to use 1,000 words to explain it. The people at NASA’s Scientific Visualization Studio (SVS) know this, and they’re experts. Every year they release a simulation of the Moon that shows what the Moon will look like to us each day.

NASA’s Moon simulator uses images and data captured by the Lunar Reconnaissance Orbiter (LRO) to recreate the Moon on each hour of each day of each month in 2018. You can input any date and time to view the Moon (Dial-a-Moon) as it will appear at that time. You can also watch a video of the Moon over the course of the entire year. Along the way, you might learn something.

December 28, 2018 by Evan Gough

Something Twice the Size of Earth Slammed into Uranus and Knocked it Over on its Side

Between 3 to 4 billion years ago, a body twice the size of Earth impacted Uranus, knocking the ice giant onto its side. Image Credit: Jacob A. Kegerreis/Durham University

Astronomers think they know how Uranus got flipped onto its side. According to detailed computer simulations, a body about twice the size of Earth slammed into Uranus between 3 to 4 billion years ago. The impact created an oddity in our Solar System: the only planet that rotates on its side.

A study explaining these findings was presented at the American Geophysical Union’s (AGU) Fall Meeting in Washington DC held between December 10th to 14th. It’s led by Jacob Kegerreis, a researcher at Durham University. It builds on previous studies pointing to an impact as the cause of Uranus’ unique orientation. Taken altogether, we’re getting a clearer picture of why Uranus rotates on its side compared to the other planets in our Solar System. The impact also explains why Uranus is unique in other ways.
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December 19, 2018 by Evan Gough

The Saturn Nebula Kind of Looks Like the Planet in a Small Telescope, But in One of the Most Powerful Telescopes on Earth, it Looks Like This

The Saturn nebula as imaged by the MUSE instrument on the ESO's Very Large Telescope. Image Credit: ESO/VLT

Saturn is an icon. There’s nothing else like it in the Solar System, and it’s something even children recognize. But there’s a distant object that astronomers call the Saturn nebula, because from a distance it resembles the planet, with its pronounced ringed shape.

The Saturn nebula bears no relation to the planet, except in shape. It’s about five thousand light years away, so in a small backyard telescope, it does resemble the planet. But when astronomers train large telescopes on it, the illusion falls apart.

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December 14, 2018 by Evan Gough

Here’s the First Image of the Sun from the Parker Solar Probe

The Parker Solar Probe's WISPR (Wide-field Imager for Solar Probe) instrument captured this image of a coronal streamer on Nov. 8th, 2018. Coronal streamers are structures of solar material within the Sun's atmosphere, the corona, that usually overlie regions of increased solar activity. The fine structure of the streamer is very clear, with at least two rays visible. The bright object near the center of the image is Mercury, and the dark spots are a result of background correction. Credits: NASA/Naval Research Laboratory/Parker Solar Probe

It’s been 124 days since the Parker Solar Probe was launched, and several weeks since it made the closest approach any spacecraft has ever made to a star. Now, scientists are getting their hands on the data from the close approach. Four researchers at the recent meeting of the American Geophysical Union in Washington, D.C. shared what they hope they can learn from the probe. They hope that data from the Parker Solar Probe will help them answer decades-old question about the Sun, its corona, and the solar wind.

Scientists who study the Sun have been anticipating this for a long time, and the waiting has been worth it.

“Heliophysicists have been waiting more than 60 years for a mission like this to be possible. The solar mysteries we want to solve are waiting in the corona.” – Nicola Fox, director of the Heliophysics Division at NASA Headquarters.

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December 12, 2018 by Evan Gough

A Supernova 2.6 Million Years Ago Could Have Wiped Out the Ocean’s Large Animals

Artist's impression of a Type II supernova. Credit: ESO

For many years, scientists have been studying how supernovae could affect life on Earth. Supernovae are extremely powerful events, and depending on how close they are to Earth, they could have consequences ranging from the cataclysmic to the inconsequential. But now, the scientists behind a new paper say they have specific evidence linking one or more supernova to an extinction event 2.6 million years ago.

About 2.6 million years ago, one or more supernovae exploded about 50 parsecs, or about 160 light years, away from Earth. At that same time, there was also an extinction event on Earth, called the Pliocene marine megafauna extinction. Up to a third of the large marine species on Earth were wiped out at the time, most of them living in shallow coastal waters.

“This time, it’s different. We have evidence of nearby events at a specific time.” – Dr. Adrian Melott, University of Kansas.

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December 11, 2018December 11, 2018 by Evan Gough

OSIRIS-REx Has Already Found Water on Bennu

The asteroid Bennu from a distance of 24 km (15) miles captured by the PolyCam on OSIRIS-REx. The spacecraft has detected water on Bennu. On the bottom right in the termination line is the large boulder. The image is a mosaic constructed of 12 images. Image Credit: NASA/Goddard/University of Arizona.

NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) has found water on the asteroid Bennu. Bennu is OSIRIS-REx’s only target, and though the spacecraft arrived at the asteroid on December 3rd, some of its instruments have been trained on the asteroid since mid-August. And two of those instruments detected water on Bennu.

OSIRIS-REx wasn’t sent to Bennu just to find water. The mission is NASA’s first asteroid sample-return mission. The presence of water on Bennu confirms what the science team hoped would be true when they selected the asteroid as the spacecraft’s destination: Bennu is an excellent target for scientific inquiry into the early Solar System.

“The presence of hydrated minerals across the asteroid confirms that Bennu, a remnant from early in the formation of the solar system, is an excellent specimen for the OSIRIS-REx mission to study the composition of primitive volatiles and organics.” – Amy Simon, OVIRS deputy instrument scientist, NASA’s Goddard Space Flight Center.

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December 6, 2018December 6, 2018 by Paul M. Sutter

Astronomers Count all the Photons in the Universe. Spoiler Alert: 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Photons

The NASA/ESA Hubble Space Telescope offers this delightful view of the crowded stellar encampment called Messier 68, a spherical, star-filled region of space known as a globular cluster. Mutual gravitational attraction amongst a cluster’s hundreds of thousands or even millions of stars keeps stellar members in check, allowing globular clusters to hang together for many billions of years. Astronomers can measure the ages of globular clusters by looking at the light of their constituent stars. The chemical elements leave signatures in this light, and the starlight reveals that globular clusters' stars typically contain fewer heavy elements, such as carbon, oxygen and iron, than stars like the Sun. Since successive generations of stars gradually create these elements through nuclear fusion, stars having fewer of them are relics of earlier epochs in the Universe. Indeed, the stars in globular clusters rank among the oldest on record, dating back more than 10 billion years. More than 150 of these objects surround our Milky Way galaxy. On a galactic scale, globular clusters are indeed not all that big. In Messier 68's case, its constituent stars span a volume of space with a diameter of little more than a hundred light-years. The disc of the Milky Way, on the other hand, extends over some 100 000 light-years or more. Messier 68 is located about 33 000 light-years from Earth in the constellation Hydra (The Female Water Snake). French astronomer Charles Messier notched the object as the sixty-eighth entry in his famous catalogue in 1780. Hubble added Messier 68 to its own impressive list of cosmic targets in this image using the Wide Field Camera of Hubble’s Advanced Camera for Surveys. The image, which combines visible and infrared light, has a field of view of approximately 3.4 by 3.4 arcminutes. Credit: Hubble/NASA/ESA

Imagine yourself in a boat on a great ocean, the water stretching to the distant horizon, with the faintest hints of land just beyond that. It’s morning, just before dawn, and a dense fog has settled along the coast. As the chill grips you on your early watch, you catch out of the corner of your eye a lighthouse, feebly flickering through the fog.

And – yes – there! Another lighthouse, closer, its light a little stronger. As you scan the horizon more lighthouses signal the dangers of the distant coast.
Continue reading “Astronomers Count all the Photons in the Universe. Spoiler Alert: 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Photons”

November 30, 2018 by Matt Williams

Prehistoric Cave Paintings Show That Ancient People Had Pretty Advanced Knowledge of Astronomy

The Lascaux Shaft Scene. Credit: Alistair Coombs

Astronomy is one of humanity’s oldest obsessions, reaching back all the way to prehistoric times. Long before the Scientific Revolution taught us that the Sun is at the center of the Solar System, or modern astronomy revealed the true extend of our galaxy and the Universe, ancient peoples were looking up at the night sky and finding patterns in the stars.

For some time, scholars believed that an understanding of complex astronomical phenomena (like the precession of the equinoxes) did not predate the ancient Greeks. However, researchers from the Universities of Edinburgh and Kent recently revealed findings that show how ancient cave paintings that date back to 40,000 years ago may in fact be astronomical calendars that monitored the equinoxes and kept track of major events.

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