Hubble Hones In On A Hypergiant's Home

Why Star Trek matters.

The Moon of Lakes and Rivers - Saturn’s moon Titan

Saturn’s moon Titan is the only world - other than earth - that we know has liquid’s pooled on its surface. Unlike Earth, Titan has lakes of liquid methane - you wouldn’t want to swim in these lakes.

Titan’s “methane cycle” is analogy to Earth’s water cycle. In the 3rd and 4th images above we can see clouds of methane in Titan’s atmosphere. Ever since NASA’s Voyager 1 spacecraft, we have known that the gases that make up Titan’s brown colored haze were hydrocarbons. The atmosphere of Titan is largely nitrogen; minor components lead to the formation of methane–ethane clouds and nitrogen-rich organic smog.

It is thanks to the Cassini spacecraft that we now understand more about the climate of Titan - though we still understand very little!

The Cassini Space craft has mapped most of the Northern polar region of Titan, this is the region that contains almost all of Titan’s lakes. Cassini is systematically sweeping across Titan and mapping the surface of this strange alien world. The image below is an example of Cassini’s mapping process:

Credit: NASA/JPL/Cassini

Here's a better breakdown of how records work! With a video, even!

Electron microscope video of a needle on a vinyl record.

Five Famous Pulsars from the Past 50 Years

Early astronomers faced an obstacle: their technology. These great minds only had access to telescopes that revealed celestial bodies shining in visible light. Later, with the development of new detectors, scientists opened their eyes to other types of light like radio waves and X-rays. They realized cosmic objects look very different when viewed in these additional wavelengths. Pulsars — rapidly spinning stellar corpses that appear to pulse at us — are a perfect example.

The first pulsar was observed 50 years ago on August 6, 1967, using radio waves, but since then we have studied them in nearly all wavelengths of light, including X-rays and gamma rays.

Typical Pulsar

Most pulsars form when a star — between 8 and 20 times the mass of our sun — runs out of fuel and its core collapses into a super dense and compact object: a neutron star. 

These neutron stars are about the size of a city and can rotate slowly or quite quickly, spinning anywhere from once every few hours to hundreds of times per second. As they whirl, they emit beams of light that appear to blink at us from space.

First Pulsar

One day five decades ago, a graduate student at the University of Cambridge, England, named Jocelyn Bell was poring over the data from her radio telescope - 120 meters of paper recordings.

Image Credit: Sumit Sijher

She noticed some unusual markings, which she called “scruff,” indicating a mysterious object (simulated above) that flashed without fail every 1.33730 seconds. This was the very first pulsar discovered, known today as PSR B1919+21.

Best Known Pulsar

Before long, we realized pulsars were far more complicated than first meets the eye — they produce many kinds of light, not only radio waves. Take our galaxy’s Crab Nebula, just 6,500 light years away and somewhat of a local celebrity. It formed after a supernova explosion, which crushed the parent star’s core into a neutron star. 

The resulting pulsar, nestled inside the nebula that resulted from the supernova explosion, is among the most well-studied objects in our cosmos. It’s pictured above in X-ray light, but it shines across almost the entire electromagnetic spectrum, from radio waves to gamma rays.

Brightest Gamma-ray Pulsar

Speaking of gamma rays, in 2015 our Fermi Gamma-ray Space Telescope discovered the first pulsar beyond our own galaxy capable of producing such high-energy emissions. 

Located in the Tarantula Nebula 163,000 light-years away, PSR J0540-6919 gleams nearly 20 times brighter in gamma-rays than the pulsar embedded in the Crab Nebula.

Dual Personality Pulsar

No two pulsars are exactly alike, and in 2013 an especially fast-spinning one had an identity crisis. A fleet of orbiting X-ray telescopes, including our Swift and Chandra observatories, caught IGR J18245-2452 as it alternated between generating X-rays and radio waves. 

Scientists suspect these radical changes could be due to the rise and fall of gas streaming onto the pulsar from its companion star.

Transformer Pulsar

This just goes to show that pulsars are easily influenced by their surroundings. That same year, our Fermi Gamma Ray Space Telescope uncovered another pulsar, PSR J1023+0038, in the act of a major transformation — also under the influence of its nearby companion star. 

The radio beacon disappeared and the pulsar brightened fivefold in gamma rays, as if someone had flipped a switch to increase the energy of the system. 

NICER Mission

Our Neutron star Interior Composition Explorer (NICER) mission, launched this past June, will study pulsars like those above using X-ray measurements.

With NICER’s help, scientists will be able to gaze even deeper into the cores of these dense and mysterious entities.

For more information about NICER, visit https://www.nasa.gov/nicer

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Merging Galaxies Have Enshrouded Black Holes

NASA - NuStar Mission patch. May 9, 2017 Black holes get a bad rap in popular culture for swallowing everything in their environments. In reality, stars, gas and dust can orbit black holes for long periods of time, until a major disruption pushes the material in. A merger of two galaxies is one such disruption. As the galaxies combine and their central black holes approach each other, gas and dust in the vicinity are pushed onto their respective black holes. An enormous amount of high-energy radiation is released as material spirals rapidly toward the hungry black hole, which becomes what astronomers call an active galactic nucleus (AGN). A study using NASA’s NuSTAR telescope shows that in the late stages of galaxy mergers, so much gas and dust falls toward a black hole that the extremely bright AGN is enshrouded. The combined effect of the gravity of the two galaxies slows the rotational speeds of gas and dust that would otherwise be orbiting freely. This loss of energy makes the material fall onto the black hole.

Image above: This illustration compares growing supermassive black holes in two different kinds of galaxies. A growing supermassive black hole in a normal galaxy would have a donut-shaped structure of gas and dust around it (left). In a merging galaxy, a sphere of material obscures the black hole (right). Image Credits: National Astronomical Observatory of Japan. “The further along the merger is, the more enshrouded the AGN will be,” said Claudio Ricci, lead author of the study published in the Monthly Notices Royal Astronomical Society. “Galaxies that are far along in the merging process are completely covered in a cocoon of gas and dust.” Ricci and colleagues observed the penetrating high-energy X-ray emission from 52 galaxies. About half of them were in the later stages of merging. Because NuSTAR is very sensitive to detecting the highest-energy X-rays, it was critical in establishing how much light escapes the sphere of gas and dust covering an AGN. The study was published in the Monthly Notices of the Royal Astronomical Society. Researchers compared NuSTAR observations of the galaxies with data from NASA’s Swift and Chandra and ESA’s XMM-Newton observatories, which look at lower energy components of the X-ray spectrum. If high-energy X-rays are detected from a galaxy, but low-energy X-rays are not, that is a sign that an AGN is heavily obscured.

NASA’s NuSTAR telescope. Image Credit: NASA

The study helps confirm the longstanding idea that an AGN’s black hole does most of its eating while enshrouded during the late stages of a merger. “A supermassive black hole grows rapidly during these mergers,” Ricci said. “The results further our understanding of the mysterious origins of the relationship between a black hole and its host galaxy.” NuSTAR is a Small Explorer mission led by Caltech and managed by NASA’s Jet Propulsion Laboratory for NASA’s Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corp., Dulles, Virginia. NuSTAR’s mission operations center is at UC Berkeley, and the official data archive is at NASA’s High Energy Astrophysics Science Archive Research Center. ASI provides the mission’s ground station and a mirror archive. JPL is managed by Caltech for NASA. Related link: Monthly Notices of the Royal Astronomical Society: https://academic.oup.com/mnras/article/468/2/1273/2939810/Growing-supermassive-black-holes-in-the-late For more information on NuSTAR, visit: http://www.nasa.gov/nustar http://www.nustar.caltech.edu Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Elizabeth Landau. Greetings, Orbiter.ch Full article

I talked about spaghettification but someone did one better and made a dang cute comic about it!

Starry Greetings!

This week’s comic: Spaghettification 

https://www.youtube.com/watch?v=OGn_w-3pjMc

http://science.howstuffworks.com/science-vs-myth/what-if/what-if-fell-into-black-hole2.htm

Ten minutes till this happens! I can’t watch it live but I’m excited to see what happens in the aftermath…

In about 20 minutes SpaceX will attempt to reuse a rocket booster they’ve already used before. If they succeed it could be a very serious step forward in space exploration capabilities.

Go SpaceX. Pleassssse…

Geocentric map of the Solar System.

Ep. 10 Spectroscopy - HD and the Void

Double digits for the podcast! To celebrate, I'm talking about something I've mentioned a lot in past episodes; spectroscopy! Hear about the history of this area of astronomical science, how it opened up new understanding about the Sun and stars a...

I’ve been dropping the word ‘spectroscopy’ with only minimal explanation for quite a few episodes now and it’s high time I expanded on this topic. Join me for the double-digit episode of this podcast to learn about the history of spectroscopes and spectroscopy, how it taught us about the Sun and stars, and what advancements were made to take spectroscopes into the 20th century.

Below the cut are sources, music credits, a vocabulary list, a timeline of all the astronomers and chemist and physicists I mention, and the transcript of this episode. Let me know what you think I should research next by messaging me here, tweeting at me at @HDandtheVoid, or asking me to my face if you know me in real life. And please check out the podcast on iTunes, rate it or review it if you’d like, subscribe, and maybe tell your friends about it if you think they’d like to listen!

(My thoughts on the next episode were probes through the ages or the transit of Venus. I could also talk about more modern spectroscopy, and I’m planning to interview a friend after the eclipse next week about her graduate-level research into the history of the universe. Let me know by the 17th and I’ll have the next podcast up on August 28th, barring any new-job-related delays.)

Glossary

absorption lines - dark spectral lines that appear in a spectroscope when a gaseous or burned-up element has light shone through it.

angstrom - a unit of length—one hundred-millionth of a centimeter—that is usually used to express wavelengths and the distances in atoms.

emission lines - bright spectral lines that appear in a spectroscope when you burn an element up.

Fraunhofer lines - a standard set of spectral absorption lines observed by Joseph von Fraunhofer. He mapped 574 lines and designated them alphabetically from red to violet in the spectrum with the letters A through K, with weaker lines assigned other, lowercase letters.

incandescent - luminous or glowing due to intense heat.

spectroscopy - the study of light from an incandescent source (or, more recently, electromagnetic radiation and other radiative energy) that has its wavelength dispersed by a prism or other spectroscopic device that can disperse an object’s wavelength. The spectra of distant astronomical objects like the Sun, stars, or nebulae are patterns of absorption lines that correspond to elements that these objects are made up of. This area of study is the major source of the study of astrophysics as well as advancements in chemistry, astronomy, and quantum mechanics.

Script/Transcript

Sources 

Prisms vs. diffraction gratings via CSIRO

Definition of ‘angstrom’ via Encyclopedia Brittanica

Definition of ‘incandescent’ via Merriam-Webster

Current uses of spectroscopy in astronomy

Some past and current satellites with spectroscopic capabilities via a John Hopkin’s professor’s old webpage

Spectral classification of stars via University of Nebraska-Lincoln

Common, A. A. “Astronomy.” In Popular Astronomy 8 (1900), 417-24. Located on Google Books preview.

Hirshfeld, Alan. Starlight Detectives. Bellevue Library Press: NY, 2014.

“the Fraunhofer lines, as they were soon to be called, originate in the sun itself, and are neither optical artifacts of the spectroscope nor the result of selective absorption of sunlight within earth’s atmosphere” (168-9).

“the flame’s radiance did not ‘fill in’ the dark D [sodium] lines , as [Kirchhoff] had expected, but reinforced the absorption of these wavelengths of light” (178).

Kirchhoff: “the dark lines of the solar spectrum … exist in the consequence of the presence, in the incandescent atmosphere of the sun, of those substances which in the spectrum of a flame produce bright lines in the same plane” (178).

“a body with a propensity to emit light at a given wavelength must have an equal propensity to absorb light at that wavelength” (178).

“expresses the wavelength of a spectral line, depending on its derivation angle and the density of grooves in the grating” (187).

“mosaic of the solar spectrum assembled from prints of twenty-eight negatives” (187).

“visual confirmation of the chemical unity of the Sun and stars” (203).

Doppler “claimed in 1842 that the perceived frequency of a wave is altered by one’s state of motion” (209).

“In Doppler’s schema, waves from a steadily approaching source are compressed: as their frequency is increased, their wavelength is shortened. Waves from a steadily receding source are stretched: as their frequency is reduced, their wavelength is elongated” (210).

“Yet history has shown that credit for an evolving theory or field, such as stellar spectrum photography, often goes not to individuals who are first to publish, but to those who most convincingly establish the validity and worth of their results” (223).

“Vogel confirmed that the Sun does not rotate as a solid body; Its rotation rate varies with solar latitude, fastest at the equator, progressively slower towards the poles” (231). 

“The deviation of the star’s G line from its solar position revealed the star’s Doppler shift and, via a mathematical formula, its line-of-sight motion” (232).

“What Pickering had accomplished for stellar spectral classification with the Henry Draper project, Campbell had accomplished for stellar radial velocities with the Lick catalog” (233).

Johnson, George. Miss Leavitt’s Stars. Atlas Books: NY, 2005.

“When Kirchhoff and Bunsen made the discovery, the existence of atoms was still controversial. Once they were discovered, the effect could be simply understood: when an atom is energized, its electrons jump into higher orbits. When they fall back down they emit various frequencies of light. Every kind of atom is built a little differently, its electrons arrayed in a specific way, resulting in a characteristic pattern. For similar reasons, if you shine a light through a gaseous substance, like hydrogen or helium, certain colors will be filtered out. The result in this case is a characteristic pattern of black ‘absorption’ lines interrupting the spectrum—another unique chemical fingerprint. (The same colors marked by the absorption lines would appear as bright emission lines if the element was burned.)” (102-103).

Rhodes, Richard. The Making of the Atomic Bomb. 2nd ed. Simon & Schuster: NY, 2012.

Timeline

William Herschel, German/English (1738-1822)

Thomas Melvill, American (1751-1832)

William Hyde Wollaston, English (1766-1828)

David Brewster, Scottish (1781-1868)

Françoise Arago, French (1786-1853)

Joseph von Fraunhofer, Bavarian (1787-1826)

William Henry Fox Talbot, English (1800–1877)

George Airy, English (1801-1892)

Christian Doppler, Austrian (1803-1853)

Robert Wilhelm Bunsen, German (1811-1899)

Anders Ångström, Swedish (1814-1874)

Lewis Morris Rutherfurd, American (1816-1892)

William Allen Miller, English (1817-1870)

Pietro Angelo Secchi, Italian (1818-1878)

Armand-Hippolyte-Louis Fizeau, French (1819-1896)

William Huggins, English (1824-1910)

Gustav Kirchhoff, German (1824-1887)

Giovanni Battista Donati, Italian (1826-1873)

James Clerk Maxwell, Scottish (1831-1879)

Henry Draper, American (1837–1882)

Mary Anna Palmer Draper, American (1839–1914)

Hermann Carl Vogel, German (1841-1907)

Edward Charles Pickering, American (1846–1919)

Margaret Lindsay Huggins, Irish/English (1848-1915)

Henry Augustus Rowland, American (1848-1901)

Williamina “Mina” Fleming, Scottish (1857–1911)

William Wallace Campbell, American (1862-1938)

Annie Jump Cannon, American (1863-1941)

Antonia Maury, American (1866-1952)

Vesto Melvin Slipher, American (1875-1969)

Edwin Hubble, American (1889-1953)

Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity

Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught

Heads up, this is tomorrow night! I hope it's clear where I am to see it but considering I'm in the Pacific Northwest, I don't have super high hopes. Get a look if you can, though! Rare to see a blue moon that's actually red :)

A Total Lunar Eclipse is Coming: 10 Things to Know

If you were captivated by August’s total solar eclipse, there’s another sky show to look forward to on Jan. 31: a total lunar eclipse!

Below are 10 things to know about this astronomical event, including where to see it, why it turns the Moon into a deep red color and more…

1. First things first. What’s the difference between solar and lunar eclipses? We’ve got the quick and easy explanation in this video:

2. Location, location, location. What you see will depend on where you are. The total lunar eclipse will favor the western U.S., Alaska, Hawaii, and British Columbia on Jan. 31. Australia and the Pacific Ocean are also well placed to see a major portion of the eclipse, if not all of it.

3. Color play. So, why does the Moon turn red during a lunar eclipse? Here’s your answer:

4. Scientists, stand by. What science can be done during a lunar eclipse? Find out HERE. 

5. Show and tell. What would Earth look like from the Moon during a lunar eclipse? See for yourself with this artist’s concept HERE. 

6. Ask me anything. Mark your calendars to learn more about the Moon during our our Reddit AMA happening Monday, Jan. 29, from 3-4 pm EST/12-1 pm PST.

7. Social cues. Make sure to follow @NASAMoon and @LRO_NASA for all of the latest Moon news leading up to the eclipse and beyond.

8. Watch year-round. Can’t get enough of observing the Moon? Make a DIY Moon Phases Calendar and Calculator that will keep all of the dates and times for the year’s moon phases right at your fingertips HERE.

Then, jot down notes and record your own illustrations of the Moon with a Moon observation journal, available to download and print from moon.nasa.gov.

9. Lesson learned. For educators, pique your students’ curiosities about the lunar eclipse with this Teachable Moment HERE.

10. Coming attraction. There will be one more lunar eclipse this year on July 27, 2018. But you might need your passport—it will only be visible from central Africa and central Asia. The next lunar eclipse that can be seen all over the U.S. will be on Jan. 21, 2019. It won’t be a blue moon, but it will be a supermoon.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.