Ask Ethan: Why Don’t We Build A Telescope Without Mirrors Or Lenses?

Take in the Surreal Beauty of Jupiter in These Incredible New Images NASA released the raw data earlier this week, allowing the public to process the beautiful images

Martian North Pole

ESA / G. Neukum (Freie Universitaet, Berlin) / Bill Dunford

Planet Jupiter, observed by the Juno probe on September 1, 2017.

The Comet and the Star Cluster : Comet Linear has become unexpectedly bright. The comet, discovered in 2000, underwent a 100-fold outburst just a week before it passed a mere 14 lunar distances from Earth late last month. The comet was captured here last week at about magnitude 6 just bright enough to be seen by the unaided eye passing in front of the distant globular star cluster M14. Comet 252/P LINEAR is one of a rare group of comets that vacillate between the Earth and Jupiter every 5 years. How the comet will evolve from here is unknown, but hopes run high that it will remain a good object for binoculars in northern skies for the next week or two. via NASA

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What’s the deal about gravitational waves?

I guess y’all have heard about the discovery gravitational waves, and the recent observation of gravity waves linked to a visual observation as well.

What are they?

Gravitational waves are disturbances in space-time that are caused by objects in motion. Objects with mass distort spacetime, and thus when they move they also create disturbances. Think moving your hand along the surface of a pond - your hand’s motion creates waves and ripples in the water. Gravity waves were theorized by Einstein when he published his paper on General Relativity in the mid 1900s, and they were finally confirmed by LIGO about a year or two ago. The discovery of gravitational waves was considered the last major test of General Relativity, meaning that everything it’s predicted has held up to testing. As these gravity waves pass through space, they stretch it in one direction and compress it in the other. Check these two gifs out for a good visualization:

What is LIGO?

Ligo, or Laser Inferometer Gravity-wave Observatory, is one of three gravity wave observatories in the world. It works by splitting a laser into two perpendicular components. The light waves travel down long tunnels, bounce off a mirror, and recombine at the intersection. The interference pattern of the two light waves is measured (interference is how two light waves interact with each other - if the peaks and troughs line up, they cancel, but if the peaks line up they add together). When a gravitational wave passes by, it stretches everything in one direction while compressing it in the other direction, then vice versa. This causes a change in the interference pattern, which is then measured. Here’s a good diagram:

If you want more information about gravity waves, check out these videos:

Sources: Image 1 2 3 4, check out the links for good explanations. 

Let me know if y’all have any questions!!! I’m happy to answer them.

Young Stellar Grouping in Cygnus X

Cygnus X hosts many young stellar groupings. The combined outflows and ultraviolet radiation from the region’s numerous massive stars have heated and pushed gas away from the clusters, producing cavities of hot, lower-density gas.

In this 8-micron infrared image, ridges of denser gas mark the boundaries of the cavities. Bright spots within these ridges show where stars are forming today.

Credit: NASA/IPAC/MSX

An irregular island

This image, courtesy of the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS), captures the glow of distant stars within NGC 5264, a dwarf galaxy located just over 15 million light-years away in the constellation of Hydra (The Sea Serpent).

Dwarf galaxies like NGC 5264 typically possess around a billion stars — just one per cent of the number of stars found within the Milky Way. They are usually found orbiting other, larger, galaxies such as our own, and are thought to form from the material left over from the messy formation of their larger cosmic relatives.

NGC 5264 clearly possesses an irregular shape — unlike the more common spiral or elliptical galaxies — with knots of blue star formation. Astronomers believe that this is due to the gravitational interactions between NGC 5264 and other galaxies nearby. These past flirtations sparked the formation of new generations of stars, which now glow in bright shades of blue.

https://www.spacetelescope.org/images/potw

Curiosity Rover: Five Years on Mars

The evening of August 5, 2012…five years ago…our Mars Curiosity rover landed on the Red Planet. 

Arriving at Mars at 10:32 p.m. PDT (morning of Aug 6 EDT), this rover would prove to be the most technologically advanced rover ever built.

Curiosity used a series of complicated landing maneuvers never before attempted. 

The specialized landing sequence, which employed a giant parachute, a jet-controlled descent vehicle and a daring “sky crane” maneuver similar to rappelling was devised because testing and landing techniques used during previous rover missions could not safely accommodate the much larger and heavier rover.

Curiosity’s mission: To determine whether the Red Planet ever was, or is, habitable to microbial life.

The car-size rover is equipped with 17 cameras, a robotic arm, specialized instruments and an on-board laboratory.

Let’s explore Curiosity’s top 5 discoveries since she landed on Mars five years ago…

1. Gale Crater had conditions suitable for life about 3.5 billion years ago

In 2013, Curiosity’s analysis of a rock sample showed that ancient Mars could have supported living microbes. Scientists identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon – some of the key chemical ingredients for life – in the powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater.

Later, in 2014, Curiosity discovered that these conditions lasted for millions of years, perhaps much longer. This interpretation of Curiosity’s findings in Gale Crater suggests ancient Mars maintained a climate that could have produced long-lasting lakes at many locations on the Red Planet.

2. Organic molecules detected at several locations

In 2014, our Curiosity rover drilled into the Martian surface and detected different organic chemicals in the rock powder. This was the first definitive detection of organics in surface materials of Mars. These Martian organics could either have formed on Mars or been delivered to Mars by meteorites. 

Curiosity’s findings from analyzing samples of atmosphere and rock powder do not reveal whether Mars has ever harbored living microbes, but the findings do shed light on a chemically active modern Mars and on favorable conditions for life on ancient Mars.

3. Present and active methane in Mars’ atmosphere

Also in 2014, our Curiosity rover measured a tenfold spike in methane, an organic chemical, in the atmosphere around the planet. This temporary increase in methane tells us there must be some relatively localized source.

Researchers used Curiosity’s onboard Sample Analysis at Mars (SAM) laboratory a dozen times in a 20-month period to sniff methane in the atmosphere. During two of those months, in late 2013 and early 2014, four measurements averaged seven parts per billion.

4. Radiation could pose health risks for humans

Measurements taken by our Curiosity rover since launch have provided us with the information needed to design systems to protect human explorers from radiation exposure on deep-space expeditions in the future. Curiosity’s Radiation Assessment Detector (RAD) was the first instrument to measure the radiation environment during a Mars cruise mission from inside a spacecraft that is similar to potential human exploration spacecraft.

The findings indicate radiation exposure for human explorers could exceed our career limit for astronauts if current propulsion systems are used. These measurements are being used to better understand how radiation travels through deep space and how it is affected and changed by the spacecraft structure itself. This, along with research on the International Space Station are helping us develop countermeasures to the impacts of radiation on the human body.

5. A thicker atmosphere and more water in Mars past

In 2015, Curiosity discovered evidence that has led scientists to conclude that ancient Mars was once a warmer, wetter place than it is today. 

To produce this more temperate climate, several researchers have suggested that the planet was once shrouded in a much thicker carbon dioxide atmosphere. You may be asking…Where did all the carbon go?

The solar wind stripped away much of Mars’ ancient atmosphere and is still removing tons of it every day. That said, 3.8 billion years ago, Mars might have had a moderately dense atmosphere, with a surface pressure equal to or less than that found on Earth.

Our Curiosity rover continues to explore the Red Planet today. On average, the rover travels about 30 meters per hour and is currently on the lower slope of Mount Sharp.

Get regular updates on the Curiosity mission by following @MarsCuriosity on Twitter.

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

This NASA/ESA Hubble Space Telescope image is chock-full of galaxies. Each glowing speck is a different galaxy, except the bright flash in the middle of the image which is actually a star lying within our own galaxy that just happened to be in the way. At the center of the image lies something especially interesting, the center of the massive galaxy cluster called WHL J24.3324-8.477, including the brightest galaxy of the cluster.

The Universe contains structures on various scales — planets collect around stars, stars collect into galaxies, galaxies collect into groups, and galaxy groups collect into clusters. Galaxy clusters contain hundreds to thousands of galaxies bound together by gravity. Dark matter and dark energy play key roles in the formation and evolution of these clusters, so studying massive galaxy clusters can help scientists to unravel the mysteries of these elusive phenomena.

Credit: ESA/Hubble & NASA