Decoding Nebulae

“Electrostatic force is that which governs the motion of the atoms. It is the force which causes them to collide and develop the life-sustaining energy of heat and light, and which causes them to aggregate in an infinite variety of ways, according to Nature’s fanciful designs, and forms all these wondrous structures we see around us. It is, in fact, if our present views be true, the most important force for us to consider in Nature.”

–Nikola Tesla 

“Tesla, Marvel Of The Future.” Brooklyn Citizen, August 22, 1897.

The Stellar Buddy System

Our Sun has an entourage of planets, moons, and smaller objects to keep it company as it traverses the galaxy. But it’s still lonely compared to many of the other stars out there, which often come in pairs. These cosmic couples, called binary stars, are very important in astronomy because they can easily reveal things that are much harder to learn from stars that are on their own. And some of them could even host habitable planets!

The birth of a stellar duo

New stars emerge from swirling clouds of gas and dust that are peppered throughout the galaxy. Scientists still aren’t sure about all the details, but turbulence deep within these clouds may give rise to knots that are denser than their surroundings. The knots have stronger gravity, so they can pull in more material and the cloud may begin to collapse.

The material at the center heats up. Known as a protostar, it is this hot core that will one day become a star. Sometimes these spinning clouds of collapsing gas and dust may break up into two, three, or even more blobs that eventually become stars. That would explain why the majority of the stars in the Milky Way are born with at least one sibling.

Seeing stars

We can’t always tell if we’re looking at binary stars using just our eyes. They’re often so close together in the sky that we see them as a single star. For example, Sirius, the brightest star we can see at night, is actually a binary system (see if you can spot both stars in the photo above). But no one knew that until the 1800s.

Precise observations showed that Sirius was swaying back and forth like it was at a middle school dance. In 1862, astronomer Alvan Graham Clark used a telescope to see that Sirius is actually two stars that orbit each other.

But even through our most powerful telescopes, some binary systems still masquerade as a single star. Fortunately there are a couple of tricks we can use to spot these pairs too.

Since binary stars orbit each other, there’s a chance that we’ll see some stars moving toward and away from us as they go around each other. We just need to have an edge-on view of their orbits. Astronomers can detect this movement because it changes the color of the star’s light – a phenomenon known as the Doppler effect.

Stars we can find this way are called spectroscopic binaries because we have to look at their spectra, which are basically charts or graphs that show the intensity of light being emitted over a range of energies. We can spot these star pairs because light travels in waves. When a star moves toward us, the waves of its light arrive closer together, which makes its light bluer. When a star moves away, the waves are lengthened, reddening its light.

Sometimes we can see binary stars when one of the stars moves in front of the other. Astronomers find these systems, called eclipsing binaries, by measuring the amount of light coming from stars over time. We receive less light than usual when the stars pass in front of each other, because the one in front will block some of the farther star’s light.

Sibling rivalry

Twin stars don’t always get along with each other – their relationship may be explosive! Type Ia supernovae happen in some binary systems in which a white dwarf – the small, hot core left over when a Sun-like star runs out of fuel and ejects its outer layers – is stealing material away from its companion star. This results in a runaway reaction that ultimately detonates the thieving star. The same type of explosion may also happen when two white dwarfs spiral toward each other and collide. Yikes!

Scientists know how to determine how bright these explosions should truly be at their peak, making Type Ia supernovae so-called standard candles. That means astronomers can determine how far away they are by seeing how bright they look from Earth. The farther they are, the dimmer they appear. Astronomers can also look at the wavelengths of light coming from the supernovae to find out how fast the dying stars are moving away from us.

Studying these supernovae led to the discovery that the expansion of the universe is speeding up. Our Nancy Grace Roman Space Telescope will scan the skies for these exploding stars when it launches in the mid-2020s to help us figure out what’s causing the expansion to accelerate – a mystery known as dark energy.

Spilling stellar secrets

Astronomers like finding binary systems because it’s a lot easier to learn more about stars that are in pairs than ones that are on their own. That’s because the stars affect each other in ways we can measure. For example, by paying attention to how the stars orbit each other, we can determine how massive they are. Since heavier stars burn hotter and use up their fuel more quickly than lighter ones, knowing a star’s mass reveals other interesting things too.

By studying how the light changes in eclipsing binaries when the stars cross in front of each other, we can learn even more! We can figure out their sizes, masses, how fast they’re each spinning, how hot they are, and even how far away they are. All of that helps us understand more about the universe.

Tatooine worlds

Thanks to observatories such as our Kepler Space Telescope, we know that worlds like Luke Skywalker’s home planet Tatooine in “Star Wars” exist in real life. And if a planet orbits at the right distance from the two stars, it could even be habitable (and stay that way for a long time).

In 2019, our Transiting Exoplanet Survey Satellite (TESS) found a planet, known as TOI-1338 b, orbiting a pair of stars. These worlds are tricker to find than planets with only one host star, but TESS is expected to find several more!

Want to learn more about the relationships between stellar couples? Check out this Tumblr post: https://nasa.tumblr.com/post/190824389279/cosmic-couples-and-devastating-breakups

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

That's true with stars. We can never see stars or planets in the 'now' bc it took the light we are seeing time to get to us.

Even the sunlight takes 8 minutes to travel from the sun to earth, so if the sun exploded, we wouldn't know for 8 minutes.

In 2015, LIGO detected some gravitational waves from something that happened 1.3 billion years ago, in the constellation, Hydra. If you were on Hydra looking at Earth rn, you'd be seeing Earth from 1.3 billion years ago. 1.3 billion years ago, we were in the Mesoproterozoic Era here on earth. Life was just beginning to develop into multi-cellular organisms.

In conclusion: yes

wait i was in a tiktok comment section for something abt space and im no scientist obviously, but what if the reason we haven't found proof of life in space yet is because light takes time to travel from there to earth. like we arent seeing what's currently happening up there just what was happening way in the past.

what is the biggest challenge in the preparation of such a mission and how do you handle it?

Gravitational Waves in the Space-Time Continuum

Einstein's Theories of Relativity

Einstein has two theories of relativity. The first is The Theory of Special Relativity (1905). This is a theory of mechanics that correctly describes the motions of objects moving near the speed of light. This theory predicts that mass increases with velocity. The equation is E=MC^2 or Energy = Mass × Speed of Light ^2.

In 1916, Einstein proposed the Theory of General Relativity, which generalized his Theory of Special Relativity and had the first predictions of gravitational waves. It implied a few things.

Space-Time is a 4-Dimensional continuum.

Principle of equivalence of gravitational and inertial mass.

This suggests that Mass-Energy distorts the fabric of space-time in a predictable way (gravitational waves). It also implies

Strong gravitational force makes time slow down.

Light is altered by gravity

Gravity in strong gravitational fields will no longer obey Newton's Inverse-Square Law.

What is Newton's Inverse-Square Law?

Newton's Inverse-Square Law suggests that the force of gravity between any two objects is inversely proportional to the square of the separation distance between the two centers.

Stephen Hawking's Theory of Everything

Stephen Hawking's Theory of Everything is the solution to Einstein's equation in his Theory of General Relativity. It says that the mass density of the universe exceeds the critical density.

Critical Density: amount of mass needed to make a universe adopt a flat geometry.

This theory states that when the universe gets too big it will crash back into its center in a "Big Crunch" creating giant black hole. The energy from this "Big Crunch" will rebound and create a new "Big Bang".

Big Crunch: hypothetical scenario for the end of the known universe. The expansion of the universe will reverse and collapse on itself. The energy generated will create a new Big Bang, creating a new universe.

Big Bang: Matter will expand from a single point from a state of high density and matter. This will mark the birth of a new universe.

Basic Facts about Gravitational Waves

Invisible "ripples" in the Space-Time Continuum

Travel at the speed of light

186,000 miles per second / 299,337.984 Kilometers per second

11,160,000 miles per minute / 17,960,279.04 Kilometers per minute

669,600,000 miles per hour / 1,077,616,742.4 Kilometers per hour

There are four (4) defined categories

Continuous

Stochastic

Burst

Compact Binary Inspiral

What is LIGO?

The first proof of the existence of gravitational waves came in 1974. 20+ years after Einstein's death.

The first physical proof came in 2015, 100 years after his theory was published. The waves were detected by LIGO.

LIGO- Laser Interferometer Gravitational-Wave Observatory

The waves detected in 2015 came from 2 black holes that collided 1.3 billion years ago in the constellation Hydra. 1.3 billion years ago multicellular life was just beginning to spread on Earth, it was before the time of the dinosaurs!

Continuous Gravitational Waves

Produced by a single spinning massive object.

Caused by imperfections on the surface.

The spin rate of the object is constant. The waves are come at a continuous frequency.

Stochastic Gravitational Waves

Smalles waves

Hardest to detect

Possibly caused by remnants of gravitational radiation left over from the Big Bang

Could possibly allow us to look at the history of the Universe.

Small waves from every direction mixed together.

Burst Gravitational Waves

Never been detected.

Like ever.

Never ever.

Not once.

Nope

No

N E V E R

We don't know anything about them.

If we learn about them they could reveal the greatest revolutionary information about the universe.

Compact Binary Inspiral Gravitational Waves

All waves detected by LIGO fall into this category.

Produced by orbiting pairs of massive and dense objects. (Neutron Stars, Black Holes)

Three (3) subclasses

Binary Neutron Star (BNS) // Two (2) Neutron Stars colliding

Binary Black Hole (BBH) // Two (2) Black Holes colliding

Neutron Star- Black Hole Binary (NSBH) // A black hole and a neutron star colliding

Each subclass creates its own unique wave pattern.

Waves are all caused by the smae mechanism called an "inspiral".

Occur over millions of years.

Over eons the objects orbit closer together.

The closer they get, the faster they spin.

Sources Used:

On The Shoulders Of Giants by Stephen Hawking

Oxford Astronomy Encyclopedia

LIGO Lab | Caltech

LIGO Lab | Caltech | MIT

The Laser Interferometer Gravitational-Wave Observatory (LIGO) consists of two widely separated installations within the United States — one

nationalgeographic.com

National Geographic: Stories of Animals, Nature, and Culture

Explore National Geographic. A world leader in geography, cartography and exploration.

NASA

National Aeronautics and Space Administration

NASA.gov brings you the latest news, images and videos from America's space agency, pioneering the future in space exploration, scientific d

@watch-out-idiot-passing-through @nasa

i may not be beautiful but at least i know a lot of useless information

Is that even possible??

That's a wrap! Thank you all for the wonderful questions.

NASA Mars Perseverance Rover Mission Engineer Chloe Sackier answered questions about how we prepared for the mission, Perseverance’s entry, descent, and landing, and what Perseverance will do once on Mars.

Check out her full Answer Time for more: Career | Preparation | Entry, Descent, & Landing | Operation

We hope you had fun today and learned a little bit about our robotic astrobiologist landing on Mars on February 18th. You won't want to miss this! Tune in to NASA TV HERE starting at 2:15 p.m. EST.

If today’s Answer Time got you excited, team up with us to #CoutdownToMars! We created a virtual Mars photo booth, have sounds of Mars to listen to and more for all you Earthlings to channel your inner Martian. Check out ways to participate HERE.

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

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