Andromeda [x]

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.  

Take a moment, look outside your window. 🌷🌼

Today is the #FirstDayOfSpring in the Northern Hemisphere, also known as the vernal equinox.

#DYK Earth’s tilted axis causes the season? Throughout the year, different parts of Earth receive the Sun’s most direct rays. So, when the North Pole tilts toward the Sun, it’s summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it’s winter in the Northern Hemisphere.

These images are of Zinnias. They are part of the flowering crop experiment that began aboard the International Space Station on Nov. 16, 2015, when NASA astronaut Kjell Lindgren activated the Veggie system and its rooting “pillows” containing zinnia seeds.

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

Ep. 18 Zombie Stars and Supernovae - HD and the Void

Zombie stars were in the news in November but get in the holiday spirit by hearing about them now! Learn about the life cycle of a star, the power of a supernova, and what undeath looks like in a star.

In November, a couple lovely people brought my attention to articles about a recent discovery that headlines consistently referred to as the ‘zombie star.’ What the heck is a zombie star? What makes it a zombie? I found a zombie star from 2014 in addition to the one in 2017 and I dug into the life cycle of the average star to get a sense of what undeath looks like in stars.

Below the cut are my sources, music credits, a vocab list, and the transcript of this episode. Suggest 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. Please subscribe on iTunes, rate it and maybe review it, and tell friends if you think they’d like to hear it! Also, welcome if you found me through PodCon!

(My thoughts on the next episode are the International Space Station, the transit of Venus, or astronaut training practices. The next episode will allegedly be up on New Year’s Day, January 1st. We’ll see about that.)

Glossary

Chandrasekhar limit - the upper limit for the mass of an astronomical body that can support extreme density without imploding: about 1.4 times the mass of our Sun. Any white dwarf star that has less than that mass will stay a white dwarf forever; any star that exceeds the Chandrasekhar limit will end in a supernova. 

dwarf nova - a close binary system of a red dwarf, a white dwarf, and an accretion disk around the white dwarf. They brighten by 2 to 6 magnitudes depending on the stability of the disk, which loses material to the white dwarf. Categorized as a cataclysmic variable.

neutron star - a type of star that has gone supernova, when the surviving core is 1.5 to 3 solar masses and contracts into a small, very dense, very fast-spinning star.

nova - a close binary system of a white dwarf and a secondary star that’s a little cooler than the Sun. The system brightens 7 to 16 magnitudes in 1 to 100 days, and then the star fades slowly to the initial brightness over a period of several years or decades. At maximum brightness, it’s similar to an A or F giant star. Recurrent novae are similar to this category of variable but have several outbursts during their recorded history. Categorized as a cataclysmic variable.

pulsar - a type of neutron star that spins very, very fast. Also a kind of variable star that emits light pulses usually between 0.0014 seconds and 8.5 seconds. 

reflection telescope - reflects light rays off the concave surface of a parabolic mirror to get an image of a distant object. Higher contrast image, worse color quality. 

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.

supernova - a massive star that explodes with a magnitude increase of 20 or more. Supernovae have led us to realize that the expansion of the Universe is accelerating.

supernova progenitors - the kinds of stars and conditions that will result in certain types of supernovae.

white dwarf star - a star that has exhausted all of its nuclear fuel (i.e. no longer has hydrogen to convert into helium through nuclear fusion). It is the hot, dense core of a star. Unless it is acquiring/accreting matter from a nearby star, it will cool over time and become a dead star.

Script/Transcript

Sources

Chandrasekhar limit via PBS, Jan 2012

“The Chandrasekhar Limit is therefore not just as upper limit to the maximum mass of an ideal white dwarf, but also a threshold. A star surpassing this threshold no longer hoards its precious cargo of heavy elements. Instead, it delivers them to the universe at large in a supernova that marks its own death but makes it possible for living beings to exist.”

Type I and Type II supernovae via Space.com

Type Ia supernovae via Swinburne University of Technology

Type Ia Supernova Progenitors via Swinburne University of Technology

Zombie star via NASA, Aug 2014

Curtis McCully “I was very surprised to see anything at the location of the supernova. We expected the progenitor system would be too faint to see, like in previous searches for normal Type Ia supernova progenitors. It is exciting when nature surprises us.” 

The abstract of the article McCully and his team wrote on Type 1ax supernovae via Nature Magazine, Aug 2014

Zombie star via CNN, Nov 2017

Arcavi: "My first thought was that this must be some nearby star in our galaxy, just varying its brightness. But when we got the first spectrum of it, we saw that it was in fact a supernova 500 million light-years away. My mind was blown. The fact that it got bright and dim five times was very unusual. We'd never seen a supernova do that before."

Arcavi: "This means that we still have a lot to learn about how massive stars evolve and how they explode." 

Robert Evans via Sky and Telescope, Sept 2005

2017 zombie star articles I didn’t use because there were too many of them:

Air and Space Magazine, Nov 2017

The Atlantic, Nov 2017

BBC News, Nov 2017

BGR, Nov 2017

Carnegie Science, Nov 2017

Earth Sky, Nov 2017

Express UK, Nov 2017

The Guardian, Nov 2017

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

Filler Music: 'Toll Free’ by the Shook Twins off their album What We Do

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

Why Webb Needs to Chill

Our massive James Webb Space Telescope is currently being tested to make sure it can work perfectly at incredibly cold temperatures when it’s in deep space. 

How cold is it getting and why? Here’s the whole scoop…

Webb is a giant infrared space telescope that we are currently building. It was designed to see things that other telescopes, even the amazing Hubble Space Telescope, can’t see.  

Webb’s giant 6.5-meter diameter primary mirror is part of what gives it superior vision, and it’s coated in gold to optimize it for seeing infrared light.  

Why do we want to see infrared light?

Lots of stuff in space emits infrared light, so being able to observe it gives us another tool for understanding the universe. For example, sometimes dust obscures the light from objects we want to study – but if we can see the heat they are emitting, we can still “see” the objects to study them.

It’s like if you were to stick your arm inside a garbage bag. You might not be able to see your arm with your eyes – but if you had an infrared camera, it could see the heat of your arm right through the cooler plastic bag.

Credit: NASA/IPAC

With a powerful infrared space telescope, we can see stars and planets forming inside clouds of dust and gas.

We can also see the very first stars and galaxies that formed in the early universe. These objects are so far away that…well, we haven’t actually been able to see them yet. Also, their light has been shifted from visible light to infrared because the universe is expanding, and as the distances between the galaxies stretch, the light from them also stretches towards redder wavelengths. 

We call this phenomena  “redshift.”  This means that for us, these objects can be quite dim at visible wavelengths, but bright at infrared ones. With a powerful enough infrared telescope, we can see these never-before-seen objects.

We can also study the atmospheres of planets orbiting other stars. Many of the elements and molecules we want to study in planetary atmospheres have characteristic signatures in the infrared.

Because infrared light comes from objects that are warm, in order to detect the super faint heat signals of things that are really, really far away, the telescope itself has to be very cold. How cold does the telescope have to be? Webb’s operating temperature is under 50K (or -370F/-223 C). As a comparison, water freezes at 273K (or 32 F/0 C).

How do we keep the telescope that cold? 

Because there is no atmosphere in space, as long as you can keep something out of the Sun, it will get very cold. So Webb, as a whole, doesn’t need freezers or coolers - instead it has a giant sunshield that keeps it in the shade. (We do have one instrument on Webb that does have a cryocooler because it needs to operate at 7K.)

Also, we have to be careful that no nearby bright things can shine into the telescope – Webb is so sensitive to faint infrared light, that bright light could essentially blind it. The sunshield is able to protect the telescope from the light and heat of the Earth and Moon, as well as the Sun.  

Out at what we call the Second Lagrange point, where the telescope will orbit the Sun in line with the Earth, the sunshield is able to always block the light from bright objects like the Earth, Sun and Moon.

How do we make sure it all works in space? 

By lots of testing on the ground before we launch it. Every piece of the telescope was designed to work at the cold temperatures it will operate at in space and was tested in simulated space conditions. The mirrors were tested at cryogenic temperatures after every phase of their manufacturing process.

The instruments went through multiple cryogenic tests at our Goddard Space Flight Center in Maryland.

Once the telescope (instruments and optics) was assembled, it even underwent a full end-to-end test in our Johnson Space Center’s giant cryogenic chamber, to ensure the whole system will work perfectly in space.  

What’s next for Webb? 

It will move to Northrop Grumman where it will be mated to the sunshield, as well as the spacecraft bus, which provides support functions like electrical power, attitude control, thermal control, communications, data handling and propulsion to the spacecraft.

Learn more about the James Webb Space Telescope HERE, or follow the mission on Facebook, Twitter and Instagram.

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

Light Echoes Used to Study Protoplanetary Disks : This illustration shows a star surrounded by a protoplanetary disk. A new study uses data from NASAs Spitzer Space Telescope and four ground-based telescopes to determine the distance from a star to the inner rim of its surrounding protoplanetary disk. Researchers used a method called photo-reverberation, also known as light echoes.

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The Galactic Starburst Region NGC 3603

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This has been going on since 1995! There are so many pictures! I gotta check these out but it will take hours. Maybe treat myself to like ten a day? It’s a better way to wake up than checking Facebook right now, I like this plan.

Check out the makeshift pinhole-camera results from 99% totality! Leaves and my own hands work quite nicely to get an image of the little sliver of sunlight that was left. I had eclipse glasses but don't have any pictures from them: 99% is still not enough to reduce the sun's light very much. It got a little gloomier and I talked about it on Twitter but otherwise it was pretty uneventful! I'm glad I'm not on the road home from eclipsing. It would be cool to see totality one day, though.