一本道无码

There is a lack of baby photos of the Universe. Scientists know it was born nearly 14 billion years ago, but it didn鈥檛 start with a bang, as the name鈥擝ig Bang鈥攕uggests. Instead, the Universe was like a rapidly inflated balloon. And it was hot. Very hot.

But there is a basic question that everyone is still asking: Religion aside, will science ever explain how we got here? Cosmologists鈥攁stronomers who study the Universe鈥檚 lifespan, its birth, growth, and eventual death鈥攈ave more questions. Is there one Universe, or many? What did the Universe sound like when it was born? What is the power of its black holes鈥攃ould they eventually absorb us all? And finally鈥攖his force that started to push the Universe bigger and bigger鈥攚hat is it?

One of the rising stars in the field of cosmology and astrophysics is , an assistant professor at 一本道无码. This year, she was named an Emmy Noether Fellow, an international award for young faculty members seeking to do collaborative research. Her research on dark energy made her the , given by the .

Dark Energy

Ho鈥檚 drive comes from wanting to understand the hardest questions.聽

She wants to figure out what dark energy is. She knows what it does鈥攊t鈥檚 some mysterious component in the Universe that pushes things apart.

鈥淚n the children鈥檚 museum, when you drop a coin and it goes around and around into the center鈥攖hat鈥檚 gravity. Imagine a force that does the opposite. We鈥檙e trying to figure out what that is,鈥� Ho says.

鈥淐alculations have become pretty good at producing real Universes.鈥�

Einstein didn鈥檛 know about dark energy. In fact, nobody knew about it until 1998, when exploding stars appeared dimmer than they should have. A team of scientists used telescopes across the world to compare notes on the fading stars and came to a landmark conclusion鈥攖he stars looked dimmer because the Universe was getting bigger; the stars were farther away than they used to be. If dark energy is pushing the universe to stretch, could it, like some scientists worry, cause The Big Rip, tearing our Universe apart?

鈥淪omething was pushing the Universe apart, and we didn鈥檛 know what it was. Einstein believed that the universe was static,鈥� Ho says. Einstein had gotten some clues that the Universe was moving, but he found a way to justify his assertion, saying that space had an energy in and of itself that could resist expansion or contraction.

Ho wants to better figure out why the Universe is expanding the way it is. To do so, she is watching galaxies move with the expansion, looking for any change in how they relate to one another as they move. She hopes this can help her understand the properties of dark energy. Discovering more about dark energy could lead to undiscovered physics or new particles鈥攐r could challenge scientists to rework the theory of gravity.

How does she do it? A lot of time at the computer.

There are several sophisticated telescopes gathering data on millions of galaxies. The data are compiled into a digital catalog and given to scientists.

鈥淧eople like to call this data mining or big data鈥攔eally, I鈥檓 just looking to make sure I get all the interesting physics that you may not expect from the massive amount of data,鈥� Ho says.

She thinks of it as giving each galaxy a barcode that she can scan and check in on. Over time, she watches how the barcodes relate to one another. This helps her with another piece of her work鈥攖rying to figure out just what the Universe was like fractions of a second after the Big Bang, another conundrum about dark energy鈥攆iguring it out may mean that scientists have to rework their entire theory of the Big Bang, so Ho and other cosmologists are testing carefully any information they have around the beginning of the Universe.

She has been able to confirm that the Universe did extend very quickly in a short amount of time, and after it did so it looked like a 鈥渃osmic soup鈥� of particles.

She鈥檚 also looked into the sound waves of the early Universe, 400,000 years after the Big Bang. The sound waves are imprinted, drawing a circle-like object around each galaxy. Imagine if these circles were filled with water and that you dropped a rock into the center鈥攖hose ripples have helped determine where future galaxies are formed, meaning each galaxy has a sphere of galaxies around it.

鈥淭hese sound waves were the first cry of the Universe, when the baby was born,鈥� Ho says. Watching how galaxies formed and moved over time further helps her understand whether the Universe鈥檚 speed of expansion has changed over time, pointing to the strength of the dark energy pulling the Universe apart.

Ho鈥檚 own passion for science was born at a young age鈥攕he remembers standing as a young girl in a public library in Hong Kong, reading a biography of Marie Curie. There was not much of a night sky in the city, but regular visits to the space museum helped her start to dream. At 18, she did her first astrophysics research project at the University of California鈥揃erkeley while getting joint degrees in physics and computer science鈥攖wo fields that can be typically dominated by men. She earned her PhD in astrophysical sciences from Princeton.

At 一本道无码, the has one of the highest female-to-male ratios, illustrating the changing nature of the field. Ho keeps an international profile. She co-chairs committees for (SDSS), employing one of the most advanced telescopes, which is used by more than 40 universities; the Dark Energy Spectroscopic Instrument dark energy group, which has members from more than 20 universities; and , which has more than 40 university members from around the world.

Imagined Universes

Ho isn鈥檛 the only rising star at Carnegie Mellon. , a 一本道无码 professor of , has created some of the largest simulations of the Universe in the world. Her simulations were the first to incorporate black hole physics. has been featured on PBS鈥檚 Nova, in Astronomy Magazine, in Science News, on MSNBC鈥檚 Science and Technology, and in the Pittsburgh Post-Gazette.

Di Matteo uses theories to create her imagined Universes, where she predicts both what might happen in the future and what might have been.

鈥淚t鈥檚 fascinating that through the power of this beautiful theory we can predict the world and its reality. It can predict something that nobody has dreamed of discovering,鈥� Di Matteo says.

The most famous theory drew her to the field in the first place鈥擡instein鈥檚 landmark theory of general relativity explained how objects behave in space and time, showed how light bent due to gravity, and, most importantly to Di Matteo as a student, proved that black holes existed well before they were actually physically proven to be a reality. She was hooked.

Di Matteo鈥檚 predictions can sometimes be initiated from someone on her 一本道无码 astrophysics and cosmology team, which covers a range of research, studying theoretical, computational, and observational cosmology. The team has access to worldwide X-ray satellites, the Hubble Space Telescope, and the SDSS.

If a person from the observational side of cosmology is looking at the Universe and wondering about, say, the properties of galaxies, they鈥檒l come to her as a resource, asking, 鈥淲here did they come from? How did they form?鈥�

While they are using telescopes to observe the real Universe, Di Matteo does two things鈥攆irst she thinks up a theory to explain something, then she goes to her computer to run simulations of the Universe.

Di Matteo starts to create her model Universes by accessing a supercomputer鈥攁 computer so large, which holds so much data, that there are only a few in the United States. The computer is accessed by people all over the world and is massive in size because it holds so many details of the physics of the Universe, starting with the Big Bang and continuing until present day. However, access takes time. Scientists have to be approved by the National Science Foundation by showing that their calculations are worthy of the resources.

鈥淚f you鈥檙e looking at a galaxy, you can use that to build a picture of how the galaxy has formed stars over time.鈥�

Computers have become so fast and sophisticated that Di Matteo calls her simulations 鈥渕ock observations鈥濃�攄ata that can be just as valuable as what is actually observed with the most powerful telescopes.

When Di Matteo adds her physics and equations to the Universe鈥檚 initial condition (the moments right after the Big Bang), she has a pretty good idea where it might be going next. She can show this prediction to other astronomers, who may be waiting for 鈥渞eal鈥� data.

鈥淐alculations have become pretty good at producing real Universes,鈥� Di Matteo says.

Di Matteo also uses this model to study black holes鈥攚hich can have a mass a billion times the size of the sun鈥攕itting in the middle of galaxies. This makes her the go-to person for questions. Her 一本道无码 colleagues studying 鈥渞eal鈥� data had seen that the size of a black hole was related to the size of the surrounding galaxies鈥攂ut they didn鈥檛 know why.

鈥淗ow do black holes know about the surrounding galaxy?鈥� Di Matteo asks. 鈥淎nd why does every galaxy end up with a massive black hole in the middle?鈥�

Di Matteo starts, again, with a theory, and then starts running simulations. She creates a fake star that becomes a black hole, swallowing matter around it. It grows bigger and bigger. She notices that in some regions of the Universe, which are very dense, that the evolution speeds up, the galaxy and black hole growing together. She can take this back to the observers and compare it to what they see through their massive telescopes.

Sometimes the observations of the real Universe guide the simulations, but sometimes it鈥檚 Di Matteo鈥檚 own curiosity and testing through her models that guide new observational tools.

鈥淭he things I see in simulations鈥攎aybe one day there will be an instrument that can test my predictions,鈥� Di Matteo says.

Cosmic Structures

Complementing the research of Ho and Di Matteo is , an associate professor at 一本道无码 who is one of the best young researchers using deflected light to try to understand dark matter. She is in the midst of a five-year, $750,000 grant from the U.S. Department of Energy to study dark matter and dark energy. She was also just one of 68 researchers nationwide to receive funding from the .

Dark matter doesn鈥檛 absorb, reflect, or emit light. Scientists haven鈥檛 seen it, but they know it鈥檚 there because it has gravity, and that gravity has an effect on all matter (including galaxies) around it. But scientists don鈥檛 know much about it, despite the fact that it makes up about 85% of the matter in the Universe.

For Mandelbaum, the appeal of can be traced back to first grade when she started organizing the details of her future. She wrote out her goals: She would be 4'11". She would have brown hair. And she would be a scientist. She was wrong about the first two鈥攕he has grown taller than her younger self expected, and she has red hair. But the last prediction was correct.

鈥淚 always wanted to know how the world works,鈥� she says.

Her observational technique, called weak gravitational lensing, watches how light is deflected in distant galaxies by different matter. She can observe the impact of subtle changes in the appearances of galaxies due to gravitational lensing, the deflection of light by the gravitational influence of matter鈥攊ncluding dark matter. So even though dark matter isn鈥檛 emitting light, she can see that it鈥檚 reacting to gravity.

鈥淚t鈥檚 one of the best ways to learn about the distribution of dark matter,鈥� she says. Figuring out its distribution can help her figure out what dark matter is altogether.

Mandelbaum can study a lot of different things with weak lensing, ranging from dark energy to how galaxies relate to dark matter. If dark energy is causing the expansion of the Universe to accelerate, then it鈥檚 changing the way that galaxies are clustering due to gravity. Galaxies tend to clump together, but using lensing, Mandelbaum can watch their cosmic structures change.

In fact, it鈥檚 not a certain piece of dark matter floating here or there that concerns Mandelbaum 鈥攊t鈥檚 the larger picture they鈥檙e in and how the pieces relate to one another.

鈥淲e鈥檙e looking at the degree of clumpiness,鈥� she says. 鈥淏ecause of gravity, we know it鈥檚 not random.鈥� That clumpiness likely helped form our own galaxy; its pull of gravity counteracted the expansion of the Universe鈥攎eaning it might have saved the Milky Way from staying in the hot-mess phase.

Mandelbaum can do her work in part thanks to the SDSS, utilizing the large telescope that has created the most detailed three-dimensional pictures of the Universe. 鈥淚f you鈥檙e looking at a galaxy, you can use that to build a picture of how the galaxy has formed stars over time,鈥� she says.

She also works with a camera called the Hyper Suprime-Cam, which is on an 8-meter telescope, compared to the 2.5-meter SDSS telescope. That width can collect more light, which lets Mandelbaum look at galaxies that are farther away.

The information captured by these telescopes is essentially organized by a software team into catalogs of images, which list things like all the galaxies, their positions, and the amount of light that comes from them. This information is the foundation for many observational research papers.

However, the work that Mandelbaum needs to do is critical to this first step of cataloging, and if there are mistakes, her conclusions may be wrong. So she has to serve as the Universe鈥檚 fact-checker. She meticulously checks correlations in the data, sometimes doing 鈥渘ull tests,鈥� finding things that should equal zero if everything is done right. Her process to check all of the data can last up to a year.

For example, just like when someone walks in front of the camera as a picture is being taken, so too can things like dust in the atmosphere prevent a clear image. In a sense, Mandelbaum and her team are taking cosmic photobombs out of the picture, which is much more than just tinkering with code. To develop a solution, it isn't like wait-an-hour-on-hold IT call鈥攊t can take years.

All of this means that scientists are having to hedge their bets to draw conclusions from the data鈥攖here are a lot of partially written papers while everyone waits. Mandelbaum鈥檚 thesis took three years because the original SDSS data analysis took a long time to come together properly, and she had to work with raw telescope data to produce some of the results. But her patience and meticulous approach are getting her noticed鈥攈er mentor, James Gunn, a professor at Princeton who helped develop the SDSS telescope, praises her technique.

鈥淚t鈥檚 easy to take the data and misinterpret it.鈥� he says. 鈥淚 think she is one of the best people in the world at this business. Maybe the very best.鈥�

Universal Story

So going back to that age-old question, How did we get here?, it鈥檚 clear we鈥檙e edging closer to some answers, thanks to the research of three scientists from Carnegie Mellon鈥擲hirley Ho, Tiziana Di Matteo, and Rachel Mandelbaum鈥攚ho are helping other scientists explain what has been unexplainable. As the three accomplished women distill their data and theories to create a picture of the Universe, they are telling the Universe鈥檚 life story.