Glossary

I just watched the 4 clearly visible planets march across the sky with the moon in the center, so here’s a short guide to the night sky as the last 3 move across.

mammenxTime lapse of the milky way rolling across the night sky, flanked by the planets Jupiter, Saturn & Mars. Taken from Diskit Ladakh, this place truly has some fantastic unobstructed views of the night sky

In the Heart of the Virgo Cluster : The Virgo Cluster of Galaxies is the closest cluster of galaxies to our Milky Way Galaxy. The Virgo Cluster is so close that it spans more than 5 degrees on the sky - about 10 times the angle made by a full Moon. With its heart lying about 70 million light years distant, the Virgo Cluster is the nearest cluster of galaxies, contains over 2,000 galaxies, and has a noticeable gravitational pull on the galaxies of the Local Group of Galaxies surrounding our Milky Way Galaxy. The cluster contains not only galaxies filled with stars but also gas so hot it glows in X-rays. Motions of galaxies in and around clusters indicate that they contain more dark matter than any visible matter we can see. Pictured above, the heart of the Virgo Cluster includes bright Messier galaxies such as Markarians Eyes on the upper left, M86 just to the upper right of center, M84 on the far right, as well as spiral galaxy NGC 4388 at the bottom right. via NASA

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Voyager is so happy, because it’s the bravest satellite of all. It has gone the furthest. And it’s not lonely, because it’s talking to us. It phones home. And it tells us all about the wonderful things that it’s seeing. …There’s a whole universe to explore, and it’s just leaving our Solar System right now. It’s very brave and very lucky to be doing what it’s doing, so it’s not going to get lost. It’s traveled further than anything we’ve ever built has traveled before. It’s actually showing us the way. … It might have been safer for it to just stay home, and stay inside a building, but then it would have been sad forever, because it never would have done its purpose. It never would have discovered things. It’s all a wonderful story of great discovery and success, and it couldn’t have happened if Voyager hadn’t been brave… It’s not really the fact that everything always has a start and an end, it’s what happens in the middle that counts. What do you while you’re alive? What do you do while you’re laughing? And I think we’re doing exactly what makes Voyager joyful and as happy as it could be. Think about the fact that you’re a little bit like Voyager. In that you’re going to go see the world, and you’re going to call your mom on the phone and tell her about the wonderful things that you see. … You wouldn’t want to spend your whole life hiding under your bed and never seeing anything in your whole life, you want to be able to do what makes you happy and joyful and learn about things to discover. You might be the person that discovers something really important for everybody else on the world, but you can never discover that if you just hide and only do things that are safe. So think about yourself a little bit like Voyager. What makes you laugh? It’s not just staying, hiding underneath your bed safely at home.

Cmdr. Chris Hadfield, reassuring a five-year-old who was worried about the Voyager satellite (source)

oh no I’m having feelings about a satellite

tagging Doctor Who, because.

(via reconditarmonia)

Asteroid to Fly Safely Past Earth on April 19

Asteroid Watch logo.  April 7, 2017

Artist’s impression of a Near-Earth Asteroid passing by Earth. Image Credit: ESA

A relatively large near-Earth asteroid discovered nearly three years ago will fly safely past Earth on April 19 at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance from Earth to the moon. Although there is no possibility for the asteroid to collide with our planet, this will be a very close approach for an asteroid of this size. The asteroid, known as 2014 JO25, was discovered in May 2014 by astronomers at the Catalina Sky Survey near Tucson, Arizona – a project of NASA’s NEO Observations Program in collaboration with the University of Arizona. (An NEO is a near-Earth object). Contemporary measurements by NASA’s NEOWISE mission indicate that the asteroid is roughly 2,000 feet (650 meters) in size, and that its surface is about twice as reflective as that of the moon. At this time very little else is known about the object’s physical properties, even though its trajectory is well known. The asteroid will approach Earth from the direction of the sun and will become visible in the night sky after April 19. It is predicted to brighten to about magnitude 11, when it could be visible in small optical telescopes for one or two nights before it fades as the distance from Earth rapidly increases.

Asteroid 2014 JO25

Video above: This computer-generated image depicts the flyby of asteroid 2014 JO25. The asteroid will safely fly past Earth on April 19 at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance between Earth and the moon. Video Credits: NASA/JPL-Caltech. Small asteroids pass within this distance of Earth several times each week, but this upcoming close approach is the closest by any known asteroid of this size, or larger, since asteroid Toutatis, a 3.1-mile (five-kilometer) asteroid, which approached within about four lunar distances in September 2004. The next known encounter of an asteroid of comparable size will occur in 2027 when the half-mile-wide (800-meter-wide) asteroid 1999 AN10 will fly by at one lunar distance, about 236,000 miles (380,000 kilometers). The April 19 encounter provides an outstanding opportunity to study this asteroid, and astronomers plan to observe it with telescopes around the world to learn as much about it as possible. Radar observations are planned at NASA’s Goldstone Solar System Radar in California and the National Science Foundation’s Arecibo Observatory in Puerto Rico, and the resulting radar images could reveal surface details as small as a few meters. The encounter on April 19 is the closest this asteroid has come to Earth for at least the last 400 years and will be its closest approach for at least the next 500 years. Also on April 19, the comet PanSTARRS (C/2015 ER61) will make its closest approach to Earth, at a very safe distance of 109 million miles (175 million kilometers). A faint fuzzball in the sky when it was discovered in 2015 by the Pan-STARRS NEO survey team using a telescope on the summit of Haleakala, Hawaii, the comet has brightened considerably due to a recent outburst and is now visible in the dawn sky with binoculars or a small telescope. JPL manages and operates NASA’s Deep Space Network, including the Goldstone Solar System Radar, and hosts the Center for Near-Earth Object Studies for NASA’s Near-Earth Object Observations Program, an element of the Planetary Defense Coordination Office within the agency’s Science Mission Directorate. More information about asteroids and near-Earth objects can be found at: http://cneos.jpl.nasa.gov http://www.jpl.nasa.gov/asteroidwatch For more information about NASA’s Planetary Defense Coordination Office, visit: http://www.nasa.gov/planetarydefense For asteroid and comet news and updates, follow AsteroidWatch on Twitter: https://twitter.com/AsteroidWatch Image (mentioned), Video, Text, Credits: NASA/Tony Greicius/JPL/DC Agle. Greetings, Orbiter.ch Full article

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…

Ep. 15 Dark Energy Part 2 - HD and the Void

I've talked about dark matter, now it's time to talk dark energy. Learn why it exists as a theoretical (and maybe actual) object, how we see its effects manifest in the universe, and what it means for all our theories if it is or is not real.

(I broke the last link, whoops)

Another week of theory, but no fun new particles. Instead, hear me try to say a lot of names of scientists or their eponymous equations as I talk about dark energy in the universe! Learn what some astronomers think it is and why other astronomers think there are better explanations for certain nutty galactic phenomena.

Below the cut are my sources, music credits, a vocab list, and the transcript of this episode. Let your voice be heard and tell me 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 subscribe to the podcast on iTunes, rate it and maybe review it, and tell friends if you think they’d like to listen!

(If anything about dark matter or dark energy or cosmic microwave background radiation confused you over the past few podcasts, for sure send me your questions so I can ask someone more qualified than me—my doctorate student friend! My thoughts on the next episode are still the Voyager golden records, space race history, the transit of Venus, the Moon landing, Edmond Halley, or Dark Sky Preserves and it will be up on November 20th.)

Glossary

baryons - heaviest particles. Ex. Protons, neutrons. In astroparticle physics, electrons are included in baryonic matter.

cosmic microwave background radiation - the electromagnetic radiation left over from the time of recombination in Big Bang cosmology.

dark energy - a theoretical force made up of unknown, undetectable energy. It is used to explain why the universe is expanding more rapidly over time instead of slowing its expansion.

dark matter - a theoretical mass made up of unknown particles that have not been created on Earth. It is used to explain why galaxy clusters have 10x the mass that their light output suggests they would have; why distant stars on the edges of spiral galaxies orbit at the same speed as stars near the center of the galaxy; and the accretion of gases that created galaxies at the beginning of the universe.

fundamental forces - four fundamental forces in our current model of the universe: the strong and weak nuclear forces, the electromagnetic force, and gravity.

gravitational lensing - when light from more distant sources passes near a massive star, galaxy, or galaxy cluster and the object’s gravity bends the light like a lens to provide a warped angle view of space.

Transcript

Sources

Dark energy via NASA

Dark energy via Hubble

“The strangeness of dark energy is thrilling.”

Fundamental forces via Georgia State University

Dark energy via Science Magazine (April 2017)

László Dobos: “We assume that every region of the universe determines its expansion rate itself.”

Dark energy and the South Pole Telescope via Smithsonian Magazine (April 2010)

“Knowing what dark matter is would help scientists think about how the structure of the universe forms. Knowing what dark energy does would help scientists think about how that structure has evolved over time—and how it will continue to evolve.”

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

Filler Music: ‘Even The Darkness Has Arms’ by The Barr Brothers off their album The Sleeping Operator

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

If Earth had Saturn’s Rings

From an excellent post by Jason Davis

From Washington, D.C., the rings would only fill a portion of the sky, but appear striking nonetheless. Here, we see them at sunrise.

From Guatemala, only 14 degrees above the equator, the rings would begin to stretch across the horizon. Their reflected light would make the moon much brighter.

From Earth’s equator, Saturn’s rings would be viewed edge-on, appearing as a thin, bright line bisecting the sky.

At the March and September equinoxes, the Sun would be positioned directly over the rings, casting a dramatic shadow at the equator.

At midnight at the Tropic of Capricorn, which sits at 23 degrees south latitude, the Earth casts a shadow over the middle of the rings, while the outer portions remain lit.

via x

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.

I mention New Horizons in today’s podcast but here’s some more up-to-date info!

Solar System: Things to Know This Week

Time for a little reconnaissance. 

Our New Horizons spacecraft won’t arrive at its next destination in the distant Kuiper Belt—an object known as 2014 MU69—until New Year’s Day 2019, but researchers are already starting to study its environment thanks to a few rare observational opportunities this summer, including one on July 17. This week, we’re sharing 10 things to know about this exciting mission to a vast region of ancient mini-worlds billions of miles away.

1. First, Some Background 

New Horizons launched on Jan. 19, 2006. It swung past Jupiter for a gravity boost and scientific studies in February 2007, and conducted a six-month reconnaissance flyby study of Pluto and its moons in summer 2015. The mission culminated with the closest approach to Pluto on July 14, 2015. Now, as part of an extended mission, the New Horizons spacecraft is heading farther into the Kuiper Belt.

2. A Kuiper Belt refresher

The Kuiper Belt is a region full of objects presumed to be remnants from the formation of our solar system some 4.6 billion years ago. It includes dwarf planets such as Pluto and is populated with hundreds of thousands of icy bodies larger than 62 miles (100 km) across and an estimated trillion or more comets. The first Kuiper Belt object was discovered in 1992.

3. That’s Pretty Far

When New Horizons flies by MU69 in 2019, it will be the most distant object ever explored by a spacecraft. This ancient Kuiper Belt object is not well understood because it is faint, small, and very far away, located approximately 4.1 billion miles (6.6 billion km) from Earth.

4. Shadow Play 

To study this distant object from Earth, the New Horizons team have used data from the Hubble Space Telescope and the European Space Agency’s Gaia satellite to calculate where MU69 would cast a shadow on Earth’s surface as it passes in front of a star, an event known as an occultation.

5. An International Effort 

One occultation occurred on June 3, 2017. More than 50 mission team members and collaborators set up telescopes across South Africa and Argentina, aiming to catch a two-second glimpse of the object’s shadow as it raced across the Earth. Joining in on the occultation observations were NASA’s Hubble Space Telescope and Gaia, a space observatory of the European Space Agency (ESA).

6. Piecing Together the Puzzle 

Combined, the pre-positioned mobile telescopes captured more than 100,000 images of the occultation star that can be used to assess the Kuiper Belt object’s environment. While MU69 itself eluded direct detection, the June 3 data provided valuable and surprising insights. “These data show that MU69 might not be as dark or as large as some expected,” said occultation team leader Marc Buie, a New Horizons science team member from Southwest Research Institute in Boulder, Colorado.

7. One Major Missing Piece 

Clear detection of MU69 remains elusive. “These [June 3 occultation] results are telling us something really interesting,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute. “The fact that we accomplished the occultation observations from every planned observing site but didn’t detect the object itself likely means that either MU69 is highly reflective and smaller than some expected, or it may be a binary or even a swarm of smaller bodies left from the time when the planets in our solar system formed.”

8. Another Opportunity 

On July 10, the SOFIA team positioned its aircraft in the center of the shadow, pointing its powerful 100-inch (2.5-meter) telescope at MU69 when the object passed in front of the background star. The mission team will now analyze that data over the next few weeks, looking in particular for rings or debris around MU69 that might present problems for New Horizons when the spacecraft flies by in 2019. “This was the most challenging occultation observation because MU69 is so small and so distant,” said Kimberly Ennico Smith, SOFIA project scientist.

9. The Latest 

On July 17, the Hubble Space Telescope will check for debris around MU69 while team members set up another “fence line” of small mobile telescopes along the predicted ground track of the occultation shadow in southern Argentina.

10. Past to Present 

New Horizons has had quite the journey. Check out some of these mission videos for a quick tour of its major accomplishments and what’s next for this impressive spacecraft.

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

The Science of Interstellar - Black Hole [YouTube Video]