Honestly I Don’t Really Understand Why They Didn’t Call The APOLLO Missions The ARTEMIS Missions!

The search for another Earth is super cool even if it might never end lol

But like, Aliens.

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Are We Alone? How NASA Is Trying to Answer This Question.

One of the greatest mysteries that life on Earth holds is, “Are we alone?”

At NASA, we are working hard to answer this question. We’re scouring the universe, hunting down planets that could potentially support life. Thanks to ground-based and space-based telescopes, including Kepler and TESS, we’ve found more than 4,000 planets outside our solar system, which are called exoplanets. Our search for new planets is ongoing — but we’re also trying to identify which of the 4,000 already discovered could be habitable.

Unfortunately, we can’t see any of these planets up close. The closest exoplanet to our solar system orbits the closest star to Earth, Proxima Centauri, which is just over 4 light years away. With today’s technology, it would take a spacecraft 75,000 years to reach this planet, known as Proxima Centauri b.

How do we investigate a planet that we can’t see in detail and can’t get to? How do we figure out if it could support life?

This is where computer models come into play. First we take the information that we DO know about a far-off planet: its size, mass and distance from its star. Scientists can infer these things by watching the light from a star dip as a planet crosses in front of it, or by measuring the gravitational tugging on a star as a planet circles it.

We put these scant physical details into equations that comprise up to a million lines of computer code. The code instructs our Discover supercomputer to use our rules of nature to simulate global climate systems. Discover is made of thousands of computers packed in racks the size of vending machines that hum in a deafening chorus of data crunching. Day and night, they spit out 7 quadrillion calculations per second — and from those calculations, we paint a picture of an alien world.

While modeling work can’t tell us if any exoplanet is habitable or not, it can tell us whether a planet is in the range of candidates to follow up with more intensive observations. 

One major goal of simulating climates is to identify the most promising planets to turn to with future technology, like the James Webb Space Telescope, so that scientists can use limited and expensive telescope time most efficiently.

Additionally, these simulations are helping scientists create a catalog of potential chemical signatures that they might detect in the atmospheres of distant worlds. Having such a database to draw from will help them quickly determine the type of planet they’re looking at and decide whether to keep observing or turn their telescopes elsewhere.

Learn more about exoplanet exploration, here. 

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

More nebulae!!!

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M27: Not a Comet : While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets. This is number 27 on his now famous not-a-comet list. In fact, 21st century astronomers would identify it as a planetary nebula, but it’s not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is an excellent example of a gaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star’s outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star’s intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula. This impressive color composite highlights details within the well-studied central region and fainter, seldom imaged features in the nebula’s outer halo. It incorporates broad and narrowband images recorded using filters sensitive to emission from hydrogen and oxygen atoms. via NASA

THE LIFE OF A STAR: A STAR IS BORN

All you need to make a star is dust, gravity, and time.

        Stars form from nebulae's molecular clouds - which are "clumpy, with regions containing a wide range of densities—from a few tens of molecules (mostly hydrogen) per cubic centimetre to more than one million." Stars are only made in the densest regions - cloud cores - and larger cloud cores create more massive stars. Stars also form in associations in these cores. Cores with higher percentages of mass used only for star formation will have more stars bound together, while lower percentages will have stars drifting apart. 

        These cloud cores rotate very slowly and its mass is highly concentrated in its center - while also spinning and flattening into a disk (Britannica: Star Formation). This concentration is caused by gravity. As the mass of the clump increases - it is very cold and close to absolute zero, which increases density and causes atoms to bind together into molecules such as CO and H2 - it's gravity increases and at a certain point, it will collapse under it (Uoregon). The pressure, spinning, and compressing create kinetic energy which continues to heat the gas and increase density.

        Finally, there's the last ingredient: time. The process of these molecular clouds clumping, spinning, concentrating, and collapsing takes quite a while. From start (the cloud core-forming) to finish (the birth of a main-sequence star) - the average time is at about a cool 10 million years (yikes). Of course, this differs with density and mass, but this is the time for a typical solar-type star (StackExchange).

        The next stage in a star's life - after the nebulae - is a protostar.

        After one clump separates from the cloud core, it develops its own identity and gravity, and loose gas falls into the center. This releases more kinetic energy and heats the gas, as well as the pressure. This clump will collapse under gravity, grow in density in the center. and trap infrared light inside (causing it to become opaque) (Uoregon).

        A protostar looks like a normal star - emitting light - but it's just a baby star. Protostars' cores are not hot enough to undergo nuclear fusion and the light they emit (instead of coming from the release of photons after the fusion of atoms) comes from the heat of the protostar as it contracts under gravity. By the time this is formed, the spinning and gravity have flattened the dust and gas into a protostellar disk. The rotation also generates a magnetic field - which generates a protostellar wind - and sometimes even streams or jets of gas into space (LCO).    

        This protostar, which is not much bigger than Jupiter, continues to grow by taking in more dust and gas. The light emitted absorbs dust and is remitted over and over again, resulting in a shift to longer wavelengths and causing the protostar to emit infrared light. The growth of the star is halted as jets of material stream out from the poles - the cause of this has been unidentified, although theories suggest that strong magnetic fields and rotation "act as whirling rotary blades to fling out the nearby gas." (Britannica: Star Formation)

        The "infall" of stars stops by pressure, and the protostar becomes more stable. Eventually, the temperature grows so hot (a few million kelvins) that thermonuclear fusion begins - usually in the form of deuterium (a heavier form of hydrogen), lithium, beryllium, and boron - which radiates light and energy. This starts the pre-main-sequence star phase - also called T Tauri stars - which includes lots of surface activity in the form of flares, stellar winds, opaque circumstellar disks, and stellar jets. In this phase, the star begins to contract - it can lose almost 50% of its mass - and the more massive the star, the shorter the T Tauri phase (Uoregon).

        Eventually, when the star's core becomes hot enough (in some cases, we'll touch on this later), it will begin to fuse hydrogen. This will produce "an outward pressure that balances with the inward pressure caused by gravity, stabilizing the star." (Space.com)

        This will either create an average-sized star or a massive star.

        Nuclear fusion marks the beginning of the main sequence star. A star is born.

        But it isn't always.

        Now that we've discussed the transition from nebulae to main-sequence star, we'll be talking about what happens when hydrogen fusion doesn't occur. Those are called Brown Dwarfs.

        Brown Dwarfs are those stars that form much too small - less than 0.08 the sun's mass - and as a result, they cannot undergo hydrogen fusion (Space.com).

        Brown Dwarfs, are, bigger than planets. They are roughly between the size of Jupiter and our sun. Like protostars, brown dwarfs start by fusing deuterium, and their cores contract and increase in heat as they do so. Brown Dwarfs, however, cannot contract to the size required to heat the core enough to fuse hydrogen. Their cores are dense enough to hold themselves up with pressure. They are much colder compared to main-sequence stars, ranging from 2,800 K to 300 K (the sun is 5,800 K). They are called "Brown Dwarfs" because objects below 2,200 often cold too much and develop minerals in their atmosphere, turning a brown-red color (Britannica: Brown Dwarf).

        Once Brown Dwarfs have fused all of their deuterium, they glow infrared, and the force of gravity overcomes internal pressure (the internal force of nuclear fusion used to keep it stable) as it slowly collapses. They eventually cool down and become dark balls of gas - black dwarfs (NRAO).

        Now that we've covered how stars form - and what happens in certain cases where they are not - we'll be moving to the actual life of a star. Before we talk about the end of a star's life (arguably - my favorite part) we need to discuss main-sequence, cycles, mass, heat, pressure, structure, and more. This is to understand how a star died the way it did.

        Because - when it comes to the menu of star death - stars have a few options to choose from.

First -  Chapter 1: An Introduction

Previous -  Chapter 3: Star Nurseries

Next -  Chapter 5: A Day in the Life

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I'm watching the launch now, half an hour to go!

This is the first NASA astronaut launch since 2011. I wanted to go to Cape Canaveral to watch but instead I'm watching from afar :)

(Edit: they’ve put off the launch till Saturday due to weather)

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Oo

I haven’t done a lot of research on comets. Maybe one day I’ll do an article on one, in the future. They sound so cool xD

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Comet Halley vs Comet SWAN via NASA https://ift.tt/2y0UdFr

The pre-dawn hours of May 3rd were moonless as grains of cosmic dust streaked through southern skies above Reunion Island. Swept up as planet Earth plowed through dusty debris streams left behind periodic Comet 1/P Halley, the annual meteor shower is known as the Eta Aquarids. This inspired exposure captures a bright aquarid meteor flashing left to right over a sea of clouds. The meteor streak points back to the shower’s radiant in the constellation Aquarius, well above the eastern horizon and off the top of the frame. Known for speed Eta Aquarid meteors move fast, entering the atmosphere at about 66 kilometers per second, visible at altitudes of 100 kilometers or so. Then about 6 light-minutes from Earth, the pale greenish coma and long tail of Comet C/2020 F8 SWAN were not to be left out of the celestial scene, posing above the volcanic peaks left of center. Now in the northern sky’s morning twilight near the eastern horizon Comet SWAN has not become as bright as anticipated though. This first time comet made its closest approach to planet Earth only two days ago and reaches perihelion on May 27.

(Published May 14, 2020)

Wow, Mars is one of the closest planets to us xD

Just shows you how massive space really is

(Maybe even infinitely so)

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This is what the Earth looks like from the surface of our red neighbour, Mars!

Happy Earth day everyone 🌎🌍🌏 Hope you’re all staying safe!!

Image Credit: NASA’s Curiosity Mars Rover

Can I go to Lake Thetis? Damn.

Florida’s got nothing on this place, I’m sorry. 

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Milky Way + Stromatolites - Lake Thetis, Western Australia

Nikon d5500 - 35mm - 9 x 13s - ISO 3200 - f/2.2

The rickroll is basically all scientists in a nutshell

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Let’s keep asking questions…

Galileo, what a man

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Reality is often disappointing

I love supermassive black holes!!!

Expect this in the chapter about black holes lol

The relationship between SBHs and their host galaxies are so cool!

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AAS NOVA

A Young Population of Hidden Jets

By Susanna Kohler

Looking for a fireworks show this 4th of July? Try checking out the distant universe, where powerful jets flung from supermassive black holes slam into their surroundings, lighting up the sky.

Though these jets are hidden behind shrouds of gas and dust, a new study has now revealed some of these young powerhouses.

A Galaxy–Black-Hole Connection

In the turbulent centers of active galaxies (active galactic nuclei, or AGN), gas and dust rains onto supermassive black holes of millions to billions of solar masses, triggering dramatic jets that plow into the surrounding matter and light up across the electromagnetic spectrum.

The growth of a supermassive black hole is thought to be closely tied to the evolution of its host galaxy, and feedback like these jets may provide that link. As the jets collide with the gas and dust surrounding the galaxy’s nucleus, they can trigger a range of effects — from shock waves that drive star formation, to gas removal that quenches star formation.

To better understand the connections between supermassive black holes and their host galaxies, we’d especially like to observe AGN at a time known as Cosmic Noon. This period occurred around 10 billion years ago and marks a time when star formation and supermassive black hole growth was at its strongest.

The Hidden World of Cosmic Noon

But there’s a catch: around Cosmic Noon, galaxies were heavily shrouded in thick gas and dust. This obscuring material makes it difficult for us to observe these systems in short wavelengths like optical and X-ray. Instead, we have to get creative by searching for our targets at other wavelengths.

Since AGN emission is absorbed by the surrounding dust and re-radiated in infrared, we can use infrared brightness to find obscured but luminous sources. To differentiate between hidden clumps of star formation and hidden AGN, we also look for a compact radio source — a signature that points to a jet emitted from a central black hole.

A team of scientists led by Pallavi Patil (University of Virginia and the National Radio Astronomy Observatory) has now gone on the hunt for these hidden sources at Cosmic Noon.

Newly-Triggered Jets Caught in the Act

Patil and collaborators observed a sample of 155 infrared-selected sources, following up with high-resolution imaging from the Jansky Very Large Array to identify compact radio sources. From their observations and modeling of the jets, the authors estimate these sources’ properties.

The authors find bright luminosities, small sizes, and high jet pressures — all of which suggest that we’ve caught newly-triggered jets in a short-lived, unique phase of AGN evolution where the jets are still embedded in the dense gas reservoirs of their hosts. The jets are expanding slowly because they have to work hard to push through the thick clouds of surrounding material. Over time, the jets will likely expand to larger scales and clear out the surrounding matter, causing the sources to evolve into more classical looking radio galaxies.

What’s next? The authors are currently working on a companion study to further explore the shapes of the jets and their immediate environments. These young, hidden sources will provide valuable insight into how supermassive black holes evolve alongside their host galaxies.

Citation “High-resolution VLA Imaging of Obscured Quasars: Young Radio Jets Caught in a Dense ISM,” Pallavi Patil et al 2020 ApJ 896 18. doi:10.3847/1538-4357/ab9011

TOP IMAGE….Artist’s impression of a galaxy forming stars, as powerful jets that are flung from its central black hole collide with the surrounding matter. [ESO/M. Kornmesser]

CENTRE IMAGE….This composite image of Centaurus A shows an example of large-scale jets launched from an AGN, which can eventually extend far beyond the galaxy, as seen here. [ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)]

LOWER IMAGE….The redshift distribution of the authors’ sample, based on spectroscopic redshifts of 71 sources. The sources span the period of peak star formation and black hole fueling around Cosmic Noon. [Patil et al. 2020]

BOTTOM IMAGE….The JVLA 10 GHz radio continuum observations for four sources in the authors’ sample. The cyan plus symbol marks the infrared-obtained source position. The color bars indicate flux in mJy/beam. [Adapted from Patil et al. 2020]