This Is An Article From Last Year, But Still Very Exciting News! I Wonder How Far It’s Progressed Since?

The Science of Interstellar - Black Hole [YouTube Video]

Star Discovered in Closest Known Orbit Around Likely Black Hole

NASA - Chandra X-ray Observatory patch. Astronomers have found evidence for a star that whips around a black hole about twice an hour. This may be the tightest orbital dance ever witnessed for a likely black hole and a companion star.

Image above: Artist’s illustration of a star found in the closest orbit known around a black hole in the globular cluster named 47 Tucanae. Image Credits: X-ray: NASA/CXC/University of Alberta/A.Bahramian et al.; Illustration: NASA/CXC/M.Weiss. This discovery was made using NASA’s Chandra X-ray Observatory as well as NASA’s NuSTAR and CSIRO’s Australia Telescope Compact Array (ATCA). The close-in stellar couple – known as a binary – is located in the globular cluster 47 Tucanae, a dense cluster of stars in our galaxy about 14,800 light years from Earth. While astronomers have observed this binary for many years, it wasn’t until 2015 that radio observations with the ATCA revealed the pair likely contains a black hole pulling material from a companion star called a white dwarf, a low-mass star that has exhausted most or all of its nuclear fuel. New Chandra data of this system, known as X9, show that it changes in X-ray brightness in the same manner every 28 minutes, which is likely the length of time it takes the companion star to make one complete orbit around the black hole. Chandra data also shows evidence for large amounts of oxygen in the system, a characteristic feature of white dwarfs. A strong case can, therefore, be made that the companion star is a white dwarf, which would then be orbiting the black hole at only about 2.5 times the separation between the Earth and the Moon. “This white dwarf is so close to the black hole that material is being pulled away from the star and dumped onto a disk of matter around the black hole before falling in,” said first author Arash Bahramian of the University of Alberta in Edmonton, Canada, and Michigan State University in East Lansing. “Luckily for this star, we don’t think it will follow this path into oblivion, but instead will stay in orbit.”

 Although the white dwarf does not appear to be in danger of falling in or being torn apart by the black hole, its fate is uncertain.

Chandra X-ray Observatory. Image Credits: NASA/CXC

“Eventually so much matter may be pulled away from the white dwarf that it ends up only having the mass of a planet,” said co-author Craig Heinke, also of the University of Alberta. “If it keeps losing mass, the white dwarf may completely evaporate.”

 How did the black hole get such a close companion? One possibility is that the black hole smashed into a red giant star, and then gas from the outer regions of the star was ejected from the binary. The remaining core of the red giant would form into a white dwarf, which becomes a binary companion to the black hole. The orbit of the binary would then have shrunk as gravitational waves were emitted, until the black hole started pulling material from the white dwarf. The gravitational waves currently being produced by the binary have a frequency that is too low to be detected with Laser Interferometer Gravitational-Wave Observatory, LIGO, that has recently detected gravitational waves from merging black holes. Sources like X9 could potentially be detected with future gravitational wave observatories in space. An alternative explanation for the observations is that the white dwarf is partnered with a neutron star, rather than a black hole. In this scenario, the neutron star spins faster as it pulls material from a companion star via a disk, a process that can lead to the neutron star spinning around its axis thousands of times every second. A few such objects, called transitional millisecond pulsars, have been observed near the end of this spinning up phase. The authors do not favor this possibility as transitional millisecond pulsars have properties not seen in X9, such as extreme variability at X-ray and radio wavelengths. However, they cannot disprove this explanation.
 “We’re going to watch this binary closely in the future, since we know little about how such an extreme system should behave”, said co-author Vlad Tudor of Curtin University and the International Centre for Radio Astronomy Research in Perth, Australia. “We’re also going to keep studying globular clusters in our galaxy to see if more evidence for very tight black hole binaries can be found.”

 A paper describing these results was recently accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available online: https://arxiv.org/abs/1702.02167 NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations. Read More from NASA’s Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2017/47tuc/ For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra Images (mentioned), Text, Credits: NASA/Lee Mohon/Marshall Space Flight Center/Molly Porter/Chandra X-ray Center/Megan Watzke. Greetings, Orbiter.ch Full article

How much of a daily threat is "Space junk"?

Good question, as this is a serious issue and one which we must monitor constantly in order to avoid harmful impacts on the International Space Station with objects in space.  For example, the US Space Command in Colorado is monitoring all objects bigger than a few inches in order to assess any potential impact with the Space Station.  We categorize the chance of impact and if there is a high probability, we will actually use thrusters to slightly change the position of the Space Station to avoid the impact.  If it is something that we are unable to avoid, we will have the astronauts shelter in place in their spacecrafts and in case of a catastrophic impact, they will return to Earth.

Geocentric map of the Solar System.

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

Black Holes Are Real And Spectacular, And So Are Their Event Horizons

“Originally estimated to be slightly larger than its M87 counterpart, the black hole at the center of the Milky Way — known as Sagittarius A* — has not yet had its event horizon imaged. When you observe the Universe, you don’t always get what you expect; sometimes, you get what it gives you. Instead, it was M87’s black hole that came through first, which was a much brighter and a much cleaner signal.

What we’ve found is spectacular. Those dark pixels at the center of the image are actually the silhouette of the event horizon itself. The light that we observe comes from the accelerated, heated matter around it, which must emit electromagnetic radiation. Where the matter exists, it emits radio waves, and the dark circle we see is where the background radio waves are blocked by the event horizon itself.”

We have an event horizon, folks! It wasn’t the one at the center of our galaxy that came through first, but rather the one at the center of Messier 87: a black hole over 1,000 times more massive, but some 2,000 times farther away, than the one contained in the Milky Way. This is an ultramassive black hole that’s almost the size of the entire Solar System, and its event horizon is real.

Come get the full story on what we know, now that we have our image, about black holes in the aftermath of the Event Horizon Telescope!

The Crab Nebula

via reddit

Ep. 2 Cosmology - HD and the Void

Learn about some of the major cosmological models that scientists through the ages have assigned to our universe, even when the known universe was only as big as our solar system. I talk about Claudius Ptolemy, Al-Hasan Ibn al-Haytham, Nicolaus Co...

Welcome to the second episode!

Below the cut are my sources, music credits, a glossary, a timeline of all the people I mention in the podcast, and the script I was working with. I’m on Twitter @HDandtheVoid if you want to tweet at me instead of tumblr-ing me!

Let me know what you think of this episode, let me know what you think I should research next*, tell me a fun space fact… any feedback is helpful!

*(My current thoughts are henges, spectroscopy dark matter, or black holes. Let me know by April 27th so I can start researching before I put up the next podcast on May 8th!)

Glossary:

astronomy - first used to describe a field of study in the 12th century, it concerns the study of objects and matter outside the earth's atmosphere, as well as their physical and chemical properties

corpuscles - any very small particles. A precursor to atoms.

cosmology—the study of the properties of our universe as a whole.

eccentric orbit - an orbit proposed by Ptolemy’s model of the universe where each planet's circular orbit is not centered on the Earth but at a point slightly away from Earth. See an example in the link.

elliptic orbit - also known as a Kepler orbit, it is an orbital system where a smaller body, like the moon or the planets, orbits a larger body like the Earth or the Sun, with the Earth or Sun at one focus of the ellipse while the other focus is empty. See an example in the link.

epicycle - a planet’s smaller orbit around a point on the larger orbiting sphere it is assigned to. See an example in the link.

Platonic Solid - a regular, 3-dimensional, convex polyhedron constructed by regular polygonal faces with the same number of faces meeting at each vertex. Only five shapes meet these criteria: tetrahedron, cube, octahedron, dodecahedron, and icosahedron. See an example in the link.

precession of the equinoxes - also called axial precession, it is a slow and continuous change in the orientation of an astronomical body's rotational axis due to gravity. On Earth, it is seen as a westward movement of the equinoxes along the ecliptic relative to the fixed stars, opposite to the yearly motion of the Sun along the ecliptic. See an example in the link.

solar system - first used in 1704, this term describes the Sun together with the group of celestial bodies that are held by its attraction and orbit around it.

Wilkinson Microwave Anisotropy Probe—a spacecraft operating from 2001 to 2010 which measured temperature differences in the cosmic microwave background radiation leftover from the Big Bang.

Script/Transcript (It’s not exactly what I said, but it’s what I was going off of. It’s conversational and it’s less rambly than what I actually said)

Timeline of people mentioned:

Claudius Ptolemy, Greek (100-170) Al-Hasan Ibn al-Haytham, Arab (965-1040) Nicolaus Copernicus, Polish (1473-1543) Tycho Brahe, Danish (1541-1601) Giordano Bruno, Italian (1548-1600) Galileo Galilei, Italian (1564-1642) Johannes Kepler, German (1571-1630) René Descartes, French (1596-1650) Sir Isaac Newton, English (1642-1726/7) Edmond Halley, English (1656-1742) Immanuel Kant, German (1724-1804) Pierre-Simon, marquis de Laplace, French (1749-1827) William Huggins, English (1824-1910) Heber Curtis, American (1872-1942) V. M. Slipher, American (1875-1969) Albert Einstein, German (1879-1955) Harlow Shapley, American (1885-1972) Edwin Hubble, American (1889-1953)

Sources:

Mars in retrograde during Tycho’s time

History of the idea of black holes

Size of the universe since 1919, presented as a teacher resource

Timeline of cosmological models

Current cosmological model

Measuring the size of our universe via NASA, with links to further universe-size resources

19th-century size of our universe debate between Shapley and Curtis

Cosmological Constant via NASA

Cosmological Constant via HubbleSite

NASA’s breakdown of the makeup of our universe

Dark Energy via NASA

Kirshner, Robert P.  “Hubble’s Diagram and Cosmic Expansion.”  In Proceedings of the National Academy of Sciences of the United States of America 101.1 (Jan. 6, 2004), 8-13.  http://www.jstor.org/stable/3148363 [accessed 2 December 2013].

McLennan, Evan. Cosmological Evolution: Critical and Constructive. 2nd ed., Gazette-Times Press: Corvallis, OR, 1916.

Pickover, Clifford A. Archimedes to Hawking: Laws of Science and the Great Minds Behind Them. Oxford UP: NY, 2008.

Sabra, A. I.  “Configuring the Universe: Aporetic, Problem Solving, and Kinemaic Modeling as Themes of Arabic Astronomy.” In Perspectives on Science 6 (1998), 288-330.  Retrieved from http://www.mitpressjournals.org/loi/posc [accessed Oct. 4, 2013].

Shank, Michael H.  “Setting the Stage: Galileo in Tuscany, Veneto, and Rome.”  In The Church and Galileo, 57-87.  Edited by Ernan McMullin.  Notre Dame, IN: U of Notre Dame P, 2005.

Sharratt, Michael.  Galileo: Decisive Innovator.  New York: Cambridge U P, 1994.

Smith, R. W.  “The Origins of the Velocity-Distance Relation.” In Journal for the History of Astronomy 10.29 (Oct 1979), 133-165.

Westfall, Richard S.  Essays on the Trial of Galileo.  Vatican City: Vatican Observatory Foundation, 1989.

…and class notes from a class on Ancient Astronomy I took with Prof. James Evans.

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

Filler Music: ‘Epigram’ by Tycho off their album Dive

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

My microphone just arrived! Now to set it up and figure out how the hell it works....

Heya, if you like space maybe you’ll like this comic? It’s one of my favorites and it’s ending soon and it’s all online for freebies! The spaceships are fish and folks get to go around fixing up abandoned ruins in space. It’s utterly beautiful. It’s also ending this month!

We’ll make it out eventually. 

http://www.onasunbeam.com/

(New chapters coming soon)