Astronomy
esiegel | September 6, 2016"I have lost tolerance for things without meaning. There is no time for them. Does that make sense?" -Sara Seager
The discovery of a potentially habitable planet around the nearest star to our own -- Proxima Centauri -- has brought up the tantalizing possibility that this might be closest Earth-like world ever found. But it’s important to realize that as much as we’d love to find a world humans could inhabit and colonize beyond our Solar System, there’s a big difference between calling something “Earth-like” and having it actually be like Earth.
An artist’s rendition of Proxima Centauri as…
esiegel | September 5, 2016“Never look down to test the ground before taking your next step; only he who keeps his eye fixed on the far horizon will find the right road.” -Dag Hammarskjold
A black hole is a region of space that’s got so much mass in such a small volume that the escape velocity within a specific region is greater than the speed of light. We call this barrier from which light cannot escape the event horizon, and the sole arbiter of an event horizon’s size is the black hole’s mass. Since they come in a variety of sizes and a variety of distances from us, there’s a wide range of the apparent size of the…
esiegel | August 31, 2016"Otherwise we are trying to communicate with someone who doesn't exist with a system which doesn't work." -Philip K. Dick
When it comes to the now famous “Alien Megastructures” star, the observations didn’t add up. There were huge, irregular flux dips, but not a hint of infrared radiation that would indicate a circumstellar disk. Infrared radiation was the marker for a whole slew of indicators -- planetary collision debris, warped, thick disks, cometary swarms -- that could be the cause of such spectacular dips.
Image credit: Tabby Boyajian and her team of PlanetHunters, via http://sites.psu…
esiegel | August 30, 2016“These galaxies are among the most massive galaxies in the universe and are believed to have rapidly formed their stars a long time ago. However, how these galaxies formed and why have they stopped forming new stars remain mysteries.” -Tao Wang, lead author on this new study
There was once a time early on in the Universe where there were no stars, no galaxies and no clusters of galaxies at all. While stars and galaxies form very early on, after only tens or hundreds of millions of years, it takes billions of years for the first clusters to form. Yet even if we were to look back into the…
esiegel | August 30, 2016"How vast those Orbs must be, and how inconsiderable this Earth, the Theatre upon which all our mighty Designs, all our Navigations, and all our Wars are transacted, is when compared to them. A very fit consideration, and matter of Reflection, for those Kings and Princes who sacrifice the Lives of so many People, only to flatter their Ambition in being Masters of some pitiful corner of this small Spot." -Christiaan Huygens
With the big news about Proxima b and Kepler’s haul of over 3,500 new planets since its launch, the idea that planets orbit stars other than our own is so mainstream that…
esiegel | August 29, 2016"Motions of the stars tell you how much matter there is. They don’t care what form the matter is, they just tell you that it’s there." -Pieter van Dokkum
Everything in the Universe was born with the same ratios of dark matter to normal matter: approximately 5-to-1. It shows up in everything from the cosmic microwave background to galaxy clustering to internal motions of spiral and elliptical galaxies, including the Milky Way.
From simulations and inferred maps, dark matter (blue) may form some clumps, but overall exists in a massive, diffuse halo around the luminous, disk-like part of…
esiegel | August 25, 2016"Our existence in this place, this microscopic corner of the cosmos, is fleeting. With utter disregard for our wants and needs, nature plays out its grand acts on scales of space and time that are truly hard to grasp. Perhaps all we can look to for real solace is our endless capacity to ask questions and seek answers about the place we find ourselves in." -Caleb Scharf
Now that we’ve learned the nearest star to our Sun, Proxima Centauri, has a rocky planet at the right distance for liquid water, it’s time to consider how we might learn the answers to our burning questions about it and all…
esiegel | August 24, 2016"To consider the Earth as the only populated world in infinite space is as absurd as to assert that in an entire field sown with millet, only one grain will grow." -Metrodorus of Chios
Later tonight, the European Southern Observatory is expected to make an announcement, and the smart money is on the discovery of an Earth-like planet orbiting Proxima Centauri, the nearest star to our Sun. As incredibly exciting as this news is, however, it’s important to keep in mind that “Earth-like,” to an astronomer, means something very different than what we think of as “actually like Earth.”
The Earth (…
esiegel | August 23, 2016“Astronomers are greatly disappointed when, having traveled halfway around the world to see an eclipse, clouds prevent a sight of it; and yet a sense of relief accompanies the disappointment.” -Simon Newcomb
Next year, on August 21st, 2017, millions of Americans will delight in the first total solar eclipse to go from coast-to-coast in 99 years. The path of totality will range from Oregon to South Carolina, giving more than two minutes of the Sun being blocked by the Moon’s shadow to all along its central path.
Image credit: Mir / RSA, 1999, of the Moon's shadow falling on Earth, during a…
esiegel | August 16, 2016"For something to collapse, not all systems have to shut down. In most cases, just one system is enough." -Robert Kiyosaki
Do supermassive black holes form from the merger and growth of many smaller black holes, falling towards a cluster/galactic center where they find one another and grow into a behemoth? Or is there a direct-collapse mechanism at play, where a black hole thousands, tens of thousands or even hundreds of thousands of times the mass of our Sun forms spontaneously?
The X-ray and optical images of a small galaxy containing a black hole many tens of thousands of times the mass…
esiegel | August 15, 2016"All the atoms of our bodies will be blown into space in the disintegration of the solar system, to live on forever as mass or energy." -Carolyn Porco
Launched in 1997, NASA’s Cassini spacecraft has shed unprecedented views on our Solar System’s majestic, ringed world. From the discovery of new, outer rings to infrared hazes beneath its clouds to surprising storms, the nature of its rings and structure atop Saturn’s north pole, Cassini has delivered beyond any reasonable expectations.
A false-color image highlighting Saturn’s hurricane over its north pole, inside the much larger hexagon-…
esiegel | August 11, 2016“Honestly, if you're given the choice between Armageddon or tea, you don't say 'what kind of tea?” -Neil Gaiman
Enjoying the Perseid meteor shower this year, as perhaps you do every August? As you look up, the great cosmic show might have a lot more to offer than mere streaks of light, due to cometary debris brightly burning up in the Earth’s atmosphere. This year, Jupiter has slightly disturbed the debris stream, resulting in an increase in the number of meteors-per-hour, as the stream passes quite centrally through Earth’s location.
The orbital path of Comet Swift-Tuttle, which passes…
esiegel | August 10, 2016"For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return." -Leonardo da Vinci
The Universe is an awfully big place, but how certain are we that we couldn’t travel in a straight line for a very long time and simply return to our starting position? Just because we can travel through the Universe for an arbitrarily, perhaps infinitely long distance-or-time, doesn’t mean the Universe itself is infinite. It’s quite possible that it closes in on itself, and that any straight-line path will eventually return…
esiegel | August 8, 2016"Truth is tough. It will not break, like a bubble, at a touch; nay, you may kick it about all day like a football, and it will be round and full at evening." -Oliver Wendell Holmes
When isolated stars like our Sun reach the end of their lives, they're expected to blow off their outer layers in a roughly spherical configuration: a planetary nebula. But the most spectacular bubbles don't come from gas-and-plasma getting expelled into otherwise empty space, but from young, hot stars whose radiation pushes against the gaseous nebulae in which they were born.
The star powering the bubble itself,…
esiegel | August 4, 2016"My dad took me out to see a meteor shower when I was a little kid, and it was scary for me because he woke me up in the middle of the night. My heart was beating; I didn't know what he wanted to do. He wouldn't tell me, and he put me in the car and we went off, and I saw all these people lying on blankets, looking up at the sky." -Steven Spielberg
This year’s Perseid meteor shower is already underway, and will peak on the night of August 11/morning of August 12. Consistently one of the year’s best, with approximately two meteors per minute and brighter than average meteors to boot, this year…
esiegel | August 2, 2016"This suggests a lack of Cepheids in the inner 2.5 kpc region of the Galactic disc except the [Nuclear Stellar Disc]." -N. Matsunaga et al.
If you want to find where all the young stars in a galaxy are, you look for the densest regions of gas and dust: the locations where new stars and star forming regions are most likely to occur. In the Milky Way, like all spirals, we expect this to be in the galactic plane, along the spiral arms, and in the innermost region of the disk and bulge.
A multiwavelength view of the very center of the Milky Way galaxy, including X-ray, visible, infrared and…
esiegel | August 1, 2016"He ate and drank the precious Words,
his Spirit grew robust;
He knew no more that he was poor,
nor that his frame was Dust." -Emily Dickinson
When we look at spiral galaxies, we think of grand arms, star-forming regions and dust lanes lining our perspective. But unlike face-on galaxies, where everything looks the same, galaxies that appear tilted at an angle often appear to have one half far greater in its dust-richness than the other.
The Sunflower Galaxy, Messier 63, tilted relative to our line-of-sight, with one half clearly appearing dustier than the other. Image credit: ESA/Hubble…
esiegel | July 31, 2016“Even though the future seems far away, it is actually beginning right now.” -Mattie Stepanek
It's been a fantastic week here at Starts With A Bang, where we've covered even more ground than normal! First off, for those of you not following me on SoundCloud, we've got a new science podcast out, on the last star in the Universe.
Have a listen and enjoy; that's all possible thanks to the generous donations of our Patreon supporters, as are the re-runs of each article, ad-free, on a 7-day delay over on Medium. Here were the new pieces of this past week:
Will the 'Great Attractor' defeat dark…
esiegel | July 25, 2016“He who would search for pearls must dive below.” -John Dryden
If you want to know what types of stars are found all throughout a galaxy, looking at our own simply won't do: too much of it is obscured by the plane and our position within it. But there's an even more impressive galaxy -- Andromeda -- just 2.5 million light years away. And thanks to the power of the Hubble Space Telescope, we've not only resolved individual stars within it, we've resolved over a hundred million of them.
Closeup of a large region of the Andromeda galaxy's disk, containing hundreds of open star clusters (…
esiegel | July 23, 2016"We detect motion along this axis, but right now our data cannot state as strongly as we'd like whether the clusters are coming or going." -Alexander Kashlinsky
When dark energy was discovered, and the expansion of the Universe was shown to be accelerating, there was concurrently another puzzle that received much less attention: the problem of the Great Attractor. Galaxies appear to move due to both the Hubble expansion and the local gravitational field, but the gravity from the galaxies we saw didn’t account for all the motion.
The "flows" of galaxies mapped out with the mass field nearby.…