Are We Alone In The Universe?
Are we alone in the universe?
There’s never been a better time to ponder this age-old question. We now know of thousands of exoplanets – planets that orbit stars elsewhere in the universe.
So just how many of these planets could support life?
Scientists from a variety of fields — including astrophysics, Earth science, heliophysics and planetary science — are working on this question. Here are a few of the strategies they’re using to learn more about the habitability of exoplanets.
Squinting at Earth
Even our best telescopic images of exoplanets are still only a few pixels in size. Just how much information can we extract from such limited data? That’s what Earth scientists have been trying to figure out.
One group of scientists has been taking high-resolution images of Earth from our Earth Polychromatic Imaging Camera and ‘degrading’ them in order to match the resolution of our pixelated exoplanet images. From there, they set about a grand process of reverse-engineering: They try to extract as much accurate information as they can from what seems — at first glance — to be a fairly uninformative image.
Credits: NOAA/NASA/DSCOVR
So far, by looking at how Earth’s brightness changes when land versus water is in view, scientists have been able to reverse-engineer Earth’s albedo (the proportion of solar radiation it reflects), its obliquity (the tilt of its axis relative to its orbital plane), its rate of rotation, and even differences between the seasons. All of these factors could potentially influence a planet’s ability to support life.
Avoiding the “Venus Zone”
In life as in science, even bad examples can be instructive. When it comes to habitability, Venus is a bad example indeed: With an average surface temperature of 850 degrees Fahrenheit, an atmosphere filled with sulfuric acid, and surface pressure 90 times stronger than Earth’s, Venus is far from friendly to life as we know it.
The surface of Venus, imaged by Soviet spacecraft Venera 13 in March 1982
Since Earth and Venus are so close in size and yet so different in habitability, scientists are studying the signatures that distinguish Earth from Venus as a tool for differentiating habitable planets from their unfriendly look-alikes.
Using data from our Kepler Space Telescope, scientists are working to define the “Venus Zone,” an area where planetary insolation – the amount of light a given planet receives from its host star – plays a key role in atmospheric erosion and greenhouse gas cycles.
Planets that appear similar to Earth, but are in the Venus Zone of their star, are, we think, unlikely to be able to support life.
Modeling Star-Planet Interactions
When you don’t know one variable in an equation, it can help to plug in a reasonable guess and see how things work out. Scientists used this process to study Proxima b, our closest exoplanet neighbor. We don’t yet know whether Proxima b, which orbits the red dwarf star Proxima Centauri four light-years away, has an atmosphere or a magnetic field like Earth’s. However, we can estimate what would happen if it did.
The scientists started by calculating the radiation emitted by Proxima Centauri based on observations from our Chandra X-ray Observatory. Given that amount of radiation, they estimated how much atmosphere Proxima b would be likely to lose due to ionospheric escape — a process in which the constant outpouring of charged stellar material strips away atmospheric gases.
With the extreme conditions likely to exist at Proxima b, the planet could lose the equivalent of Earth’s entire atmosphere in 100 million years — just a fraction of Proxima b’s 4-billion-year lifetime. Even in the best-case scenario, that much atmospheric mass escapes over 2 billion years. In other words, even if Proxima b did at one point have an atmosphere like Earth, it would likely be long gone by now.
Imagining Mars with a Different Star
We think Mars was once habitable, supporting water and an atmosphere like Earth’s. But over time, it gradually lost its atmosphere – in part because Mars, unlike Earth, doesn’t have a protective magnetic field, so Mars is exposed to much harsher radiation from the Sun’s solar wind.
But as another rocky planet at the edge of our solar system’s habitable zone, Mars provides a useful model for a potentially habitable planet. Data from our Mars Atmosphere and Volatile Evolution, or MAVEN, mission is helping scientists answer the question: How would Mars have evolved if it were orbiting a different kind of star?
Scientists used computer simulations with data from MAVEN to model a Mars-like planet orbiting a hypothetical M-type red dwarf star. The habitable zone of such a star is much closer than the one around our Sun.
Being in the habitable zone that much closer to a star has repercussions. In this imaginary situation, the planet would receive about 5 to 10 times more ultraviolet radiation than the real Mars does, speeding up atmospheric escape to much higher rates and shortening the habitable period for the planet by a factor of about 5 to 20.
These results make clear just how delicate a balance needs to exist for life to flourish. But each of these methods provides a valuable new tool in the multi-faceted search for exoplanet life. Armed with these tools, and bringing to bear a diversity of scientific perspectives, we are better positioned than ever to ask: are we alone?
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
More Posts from Carlosalberthreis and Others
Have a nice Pi-Day! In memory of Stephen Hawking!
Reinventing the Wheel
Planning a trip to the Moon? Mars? You’re going to need good tires…
Exploration requires mobility. And whether you’re on Earth or as far away as the Moon or Mars, you need good tires to get your vehicle from one place to another. Our decades-long work developing tires for space exploration has led to new game-changing designs and materials. Yes, we’re reinventing the wheel—here’s why.
Wheels on the Moon
Early tire designs were focused on moving hardware and astronauts across the lunar surface. The last NASA vehicle to visit the Moon was the Lunar Roving Vehicle during our Apollo missions. The vehicle used four large flexible wire mesh wheels with stiff inner frames. We used these Apollo era tires as the inspiration for new designs using newer materials and technology to better function on a lunar surface.
Up springs a new idea
During the mid-2000s, we worked with industry partner Goodyear to develop the Spring Tire, an airless compliant tire that consists of several hundred coiled steel wires woven into a flexible mesh, giving the tires the ability to support high loads while also conforming to the terrain. The Spring Tire has been proven to generate very good traction and durability in soft sand and on rocks.
Spring Tires for Mars
A little over a year after the Mars Curiosity Rover landed on Mars, engineers began to notice significant wheel damage in 2013 due to the unexpectedly harsh terrain. That’s when engineers began developing new Spring Tire prototypes to determine if they would be a new and better solution for exploration rovers on Mars.
In order for Spring Tires to go the distance on Martian terrain, new materials were required. Enter nickel titanium, a shape memory alloy with amazing capabilities that allow the tire to deform down to the axle and return to its original shape.
These tires can take a lickin’
After building the shape memory alloy tire, Glenn engineers sent it to the Jet Propulsion Laboratory’s Mars Life Test Facility. It performed impressively on the punishing track.
Why reinvent the wheel? It’s worth it.
New, high performing tires would allow lunar and Mars rovers to explore greater regions of the surface than currently possible. They conform to the terrain and do not sink as much as rigid wheels, allowing them to carry heavier payloads for the same given mass and volume. Also, because they absorb energy from impacts at moderate to high speeds, there is potential for use on crewed exploration vehicles which are expected to move at speeds significantly higher than the current Mars rovers.
Airless tires on Earth
Maybe. Recently, engineers and materials scientists have been testing a spinoff tire version that would work on cars and trucks on Earth. Stay tuned as we continue to push the boundaries on traditional concepts for exploring our world and beyond.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
É um evento único, que ficará em nossas memórias.
📅 Data de registro: 5 de agosto de 2024 às 18:24
The latest results from the “Cheshire Cat” group of galaxies show how manifestations of Einstein’s 100-year-old theory can lead to new discoveries today. Astronomers have given the group this name because of the smiling cat-like appearance. Some of the feline features are actually distant galaxies whose light has been stretched and bent by the large amounts of mass, most of which is in the form of dark matter detectable only through its gravitational effect, found in the system.
Image credit: NASA / STScI / Chandra & Hubble
What’s Up for June 2017?
Have a planet party and compare Saturn and Jupiter! We’ll show you where and when to point your telescope or binoculars to see these planets and their largest moons.
Meet at midnight to have a planetary party when Jupiter and Saturn are visible at the same time!
The best time will be after midnight on June 17. To see the best details, you’ll need a telescope.
Saturn will be at opposition on June 14, when Saturn, the Earth and the sun are in a straight line.
Opposition provides the best views of Saturn and several of its brightest moons. At the very least, you should be able to see Saturn’s moon Titan, which is larger and brighter than Earth’s moon.
As mentioned earlier, you’ll be able to see Jupiter and Saturn in the night sky this month. Through a telescope, you’ll be able to see the cloud bands on both planets. Saturn’s cloud bands are fainter than those on Jupiter.
You’ll also have a great view of Saturn’s Cassini Division, discovered by astronomer Giovanni Cassini in 1675, namesake of our Cassini spacecraft.
Our Cassini spacecraft has been orbiting the planet since 2004 and is on a trajectory that will ultimately plunge it into Saturn’s atmosphere on September 15, 2017, bringing the mission to a close.
Our Juno spacecraft recently completed its sixth Jupiter flyby. Using only binoculars you can observe Jupiter’s 4 Galilean moons - Io, Callisto, Ganymede and Europa.
To learn about What’s Up in the skies for June 2017, watch the full video:
For more astronomy events, check out NASA’s Night Sky Network at https://nightsky.jpl.nasa.gov/.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
Conjunction: Mars, Venus and Moon
by Stefan Grießinger
Asas da Nuvem
No dia 2 de julho de 2018, logo pela manhã, próximo às 10 horas, quando eu fui observar o movimento no centro da cidade, percebi nesse instante um fato curioso que ocorreu no céu.
Logo de imediato, imaginei as possíveis formas que a nuvem poderia assumir, uma delas sendo um anjo e outra sendo uma borboleta. Após refletir nas possíveis formas, lembrei de um conceito que relaciona esses fatos que ocorrem no cotidiano, que é chamado de PAREIDOLIA.
A pareidolia é um fenômeno neuropsicológico que faz reconhecer um objeto familiar em um estímulo aleatório. [...]
O especialista em neuropsicologia Fabrizio Veloso, profissional associado à Sociedade Brasileira de Psicologia (SBP), afirma que: “Essa tendência de encontrar padrões com significado em imagens ou sons aleatórios está relacionada com a capacidade que o nosso cérebro possui de transformar nossas percepções em algo familiar, ou seja, relaciona-se à forma como construímos o mundo ao nosso redor”.
Assim, estímulos visuais – ou sonoros – aleatórios tendem a ser traduzidos, reconhecidos e associados por nossos cérebros a objetos e estímulos familiares. E nada mais familiar para humanos desde a infância do que outros rostos humanos, daí a frequência da identificação de faces onde elas não existem objetivamente. [...]
Se isso acontece com você, fique tranquilo. É absolutamente normal, garante a ciência.
Data de registro: 2 de julho de 2018 às 09:43
Créditos do texto: Sociedade Brasileira de Psicologia (SBP). Disponível em:
Conjunction: Mars, Venus and Moon
by Stefan Grießinger
Let History Never Forget the Name Enterprise
Just as the captains of the fictional 24th century Starfleet blazed a trail among the stars, the space shuttle Enterprise helped pave the way for future space exploration.
Fifty years ago, Star Trek debuted with the USS Enterprise as the main space-faring vessel used in much of the Star Trek universe. As such, the vessel holds a treasured place in the hearts of Star Trek fans and is as much of a character in the show as Kirk and Spock. Over three different series and a total of 14 seasons on TV and 13 feature films, the iterations of Enterprise have captured the imaginations and provided inspiration for its fans across the globe.
This brief history of the shuttle tells the tale of humanity’s first reusable spacecraft. Space shuttles were first built in the late 1970s and were flown in space from 1981 to 2011. Their missions ranged from helping to build the International Space Station to repairing the Hubble Space Telescope.
It’s All In The Name
The first shuttle was originally to be named Constitution, celebrating the country’s bicentennial and was to be unveiled to the public on Constitution Day, Sept. 17, 1976. However, a massive letter-writing campaign by Star Trek fans prompted President Gerald Ford to suggest the change. In the above photo, we see the shuttle Enterprise rolled out in Palmdale, California, with cast members of Star Trek on Sept. 17, 1976.
To Boldly Go …
This circular red, white and blue emblem was the official insignia for the Space Shuttle Approach and Landing Test flights and became a model for future space shuttle mission patch designs, including placing the names of the crew on the patch . The four astronauts listed on the patch are:
Fred Haise., commander of the first crew
Charles Fullerton, pilot of the first crew
Joe Engle, commander of the second crew
Dick Truly, pilot of the second crew
First Impressions
In this image, Enterprise makes its first appearance mated to its boosters as it is slowly rolled to the huge Vehicle Assembly Building (VAB) at Kennedy Space Center. Although she never flew in space, shuttle Enterprise underwent a series of fit and function checks on the pad in preparation for the first launch of its sister craft, Columbia.
Not Meant To Be
Enterprise sits on Launch Complex 39 at Kennedy Space Center undergoing tests after completing its 3.5 mile journey from the VAB. Have you ever wondered why Enterprise never went into space? Converting Enterprise from a training vehicle to space-worthy one was too cost prohibitive, our engineers felt.
Engage
Commander Fred Haise and pilot Charles Fullerton are seen in the cockpit of Enterprise prior to the fifth and final Approach and Landing Test at Dryden Flight Research Center (Armstrong Flight Research Center). The tests were performed to learn about the landing characteristics of the shuttle.
It’s Been An Honor To Serve With You
The Enterprise’s two crews pose for a photo op at the Rockwell International Space Division’s Orbiter assembly facility at Palmdale, California. They are (left to right) Charles Fullerton, Fred Haise, Joe Engle and Dick Truly.
Fair Winds And Following Seas
On July 6, 2012, the Enterprise, atop a barge, passes the Statue of Liberty on its way to the Intrepid Sea, Air and Space Museum, where is now permanently on display.
Learn more about Star Trek and NASA.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
Ainda estamos em 2015!! hahahah...
Terça, 36 de dezembro de 2015.
-
sophisticatedexuberance liked this · 4 months ago -
something-about-the-stars liked this · 2 years ago -
jorgiop liked this · 3 years ago -
an-abyss-called-life liked this · 3 years ago
