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WFIRST - Blog Posts

5 years ago

How Gravity Warps Light

Gravity is obviously pretty important. It holds your feet down to Earth so you don’t fly away into space, and (equally important) it keeps your ice cream from floating right out of your cone! We’ve learned a lot about gravity over the past few hundred years, but one of the strangest things we’ve discovered is that most of the gravity in the universe comes from an invisible source called “dark matter.” While our telescopes can’t directly see dark matter, they can help us figure out more about it thanks to a phenomenon called gravitational lensing.

The Gravity of the Situation

Anything that has mass is called matter, and all matter has gravity. Gravity pulls on everything that has mass and warps space-time, the underlying fabric of the universe. Things like llamas and doughnuts and even paper clips all warp space-time, but only a tiny bit since they aren’t very massive.

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But huge clusters of galaxies are so massive that their gravity produces some pretty bizarre effects. Light always travels in a straight line, but sometimes its path is bent. When light passes close to a massive object, space-time is so warped that it curves the path the light must follow. Light that would normally be blocked by the galaxy cluster is bent around it, producing intensified — and sometimes multiple — images of the source. This process, called gravitational lensing, turns galaxy clusters into gigantic, intergalactic magnifying glasses that give us a glimpse of cosmic objects that would normally be too distant and faint for even our biggest telescopes to see.

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Hubble “Sees” Dark Matter

Let’s recap — matter warps space-time. The more matter, the stronger the warp and the bigger its gravitational lensing effects. In fact, by studying “lensed” objects, we can map out the quantity and location of the unseen matter causing the distortion!

Thanks to gravitational lensing, scientists have measured the total mass of many galaxy clusters, which revealed that all the matter they can see isn’t enough to create the warping effects they observe. There’s more gravitational pull than there is visible stuff to do the pulling — a lot more! Scientists think dark matter accounts for this difference. It’s invisible to our eyes and telescopes, but it can’t hide its gravity!

The mismatch between what we see and what we know must be there may seem strange, but it’s not hard to imagine. You know that people can’t float in mid-air, so what if you saw a person appearing to do just that? You would know right away that there must be wires holding him up, even if you couldn’t see them.

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Our Hubble Space Telescope observations are helping unravel the dark matter mystery. By studying gravitationally lensed galaxy clusters with Hubble, astronomers have figured out how much of the matter in the universe is “normal” and how much is “dark.” Even though normal matter makes up everything from pickles to planets, there’s about five times more dark matter in the universe than all the normal matter combined!

WFIRST Will Escalate the Search

One of our next major space telescopes, the Wide Field Infrared Survey Telescope (WFIRST), will take these gravitational lensing observations to the next level. WFIRST will be sensitive enough to use weak gravitational lensing to see how clumps of dark matter warp the appearance of distant galaxies. By observing lensing effects on this small scale, scientists will be able to fill in more of the gaps in our understanding of dark matter.

WFIRST will observe a sky area 100 times larger than Hubble does, but with the same awesome image quality. WFIRST will collect so much data in its first year that it will allow scientists to conduct in-depth studies that would have taken hundreds of years with previous telescopes.

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WFIRST’s weak gravitational lensing observations will allow us to peer even further back in time than Hubble is capable of seeing. Scientists believe that the universe’s underlying dark matter structure played a major role in the formation and evolution of galaxies by attracting normal matter. Seeing the universe in its early stages will help scientists unravel how it has evolved over time and possibly provide clues to how it may continue to evolve. We don’t know what the future will hold, but WFIRST will help us find out.

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This science is pretty mind-bending, even for scientists. Learn more as our current and future telescopes plan to help unlock these mysteries of the universe...

Hubble: https://www.nasa.gov/mission_pages/hubble/main/index.html WFIRST: https://wfirst.gsfc.nasa.gov/

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7 years ago

We Just Identified More Than 200 New (Potential) Planets

The Kepler space telescope is our first mission capable of identifying Earth-size planets around other stars. On Monday, June 19, 2017, scientists from many countries gathered at our Ames Research Center to talk about the latest results from the spacecraft, which include the identification of more than 200 potential new worlds! Here’s what you need to know:

We found 219 new planet candidates.

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All of these worlds were found in a patch of sky near the Cygnus constellation in our Milky Way galaxy. Between 2009 and 2013, Kepler searched more than 200,000 stars in the region for orbiting planets. The 219 new planet candidates are part of the more than 4,000 planet candidates and 2,300 confirmed planets Kepler has identified to date.

Ten of these worlds are like our own.

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Out of the 219 new planet candidates, 10 are possibly rocky, terrestrial worlds and orbit their star in the habitable zone – the range of distances from a star where liquid water could pool on the surface of a rocky planet.

Small planets come in two sizes.

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Kepler has opened up our eyes to the existence of many small worlds. It turns out a lot of these planets are either approximately 1.5 times the size of Earth or just smaller than Neptune. The cool names given to planets of these sizes? Super Earths and mini-Neptunes.

Some of the new planets could be habitable. 

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Water is a key ingredient to life as we know it. Many of the new planet candidates are likely to have small rocky cores enveloped by a thick atmosphere of hydrogen and helium, and some are thought to be ocean worlds. That doesn’t necessarily mean the oceans of these planets are full of water, but we can dream, can’t we?

Other Earths are out there.

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Kepler’s survey has made it possible for us to measure the number of Earth-size habitable zone planets in our galaxy. Determining how many planets like our own that exist is the big question we’ll explore next.

The hunt for new planets continues.

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Kepler continues to search for planets in different regions of space. With the launch of our Transiting Exoplanet Survey Satellite (TESS) and the James Webb Space Telescope (JWST) in 2018, we’re going to search for planets nearest the sun and measure the composition of their atmospheres. In the mid-2020s, we have our sights on taking a picture of small planets like Earth with our Wide-Field Infrared Survey Telescope (WFIRST).

*All images of planets are artist illustrations.

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


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9 years ago

A Wider Set of Eyes on the Universe

After years of preparatory studies, we are formally starting an astrophysics mission designed to help unlock the secrets of the universe. 

Introducing…

the Wide Field Infrared Survey Telescope, aka WFIRST.

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With a view 100 times bigger than that of our Hubble Space Telescope, WFIRST will help unravel the secrets of dark energy and dark matter, and explore the evolution of the cosmos. It will also help us discover new worlds and advance the search for planets suitable for life.

WFIRST is slated to launch in the mid-2020s. The observatory will begin operations after traveling about one million miles from Earth, in a direction directly opposite the sun.

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Telescopes usually come in two different “flavors” - you have really big, powerful telescopes, but those telescopes only see a tiny part of the sky. Or, telescopes are smaller and so they lack that power, but they can see big parts of the sky. WFIRST is the best of worlds.

No matter how good a telescope you build, it’s always going to have some residual errors. WFIRST will be the first time that we’re going to fly an instrument that contains special mirrors that will allow us to correct for errors in the telescope. This has never been done in space before!

Employing multiple techniques, astronomers will also use WFIRST to track how dark energy and dark matter have affected the evolution of our universe. Dark energy is a mysterious, negative pressure that has been speeding up the expansion of the universe. Dark matter is invisible material that makes up most of the matter in our universe.

Single WFIRST images will contain over a million galaxies! We can’t categorize and catalogue those galaxies on our own, which is where citizen science comes in. This allows interested people in the general public to solve scientific problems.

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


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