image: From left to right: Florian Cabot, Sarah Kenderdine, Yves Revaz, Jean-Paul Kneib. view more
Credit: Alain Herzog / EPFL
You’re floating in space, just above the Earth. The International Space Station is an arm’s length away. You twist your head around only to see the moon, a tiny circle, far off in the distance. You can’t help but think that this is probably what an astronaut would see during a space-walk.
你正漂浮在太空中，就在地球上方。国际空间站就在咫尺之遥。当你转过头，你会看到远处的月亮，只是一个小圆圈。你不禁想到这可能是宇航员在太空行走时会看到的景。
This is the beginning of a journey into outer-space, in a virtual environment developed by EPFL scientists.
这是一场从EPFL 科学家开发的虚拟环境里开始的外太空之旅。
Now, for the very first time, you can enter the most comprehensive virtual universe based on the latest astrophysical and cosmological data, thanks to powerful, open-source software developed at EPFL’s Laboratory of Astrophysics (LASTRO). The software is called VIRUP, for Virtual Reality Universe Project, and a first beta version is being released today.
现在，借助 EPFL 天体物理实验室 (LASTRO) 开发的强大开源软件，人们第一次能够见到基于最新天体物理学和宇宙学数据的最全面的虚拟宇宙。软件名为 VIRUP，是虚拟现实宇宙项目的简称，它的第一个测试版将在今天发布。
“You can navigate through the most detailed map of the universe from the comfort of your own home,” explains Jean-Paul Kneib, director of LASTRO. “It’s the chance to travel through space, through time, and discover the universe.”
“你可以在舒适的家中浏览最详细的宇宙地图。” LASTRO 主任Jean-Paul Kneib解释道：“这是一个穿越时空、探索宇宙的机会。”
The VIRUP challenge : visualizing terabytes of data at once
VIRUP 的挑战：即时的TB级数据的可视化
Astronomers and astrophysicists are collecting data about billions of celestial objects in the night sky with the help of telescopes here on Earth and in space. There are already decades of observational data. Even greater amounts of data are expected in the near future.
天文学家和天体物理学家正在地球和太空中的望远镜的帮助下，收集夜空中数十亿个天体的数据。至今人类已经积累了几十年的观测数据，预计在不久的将来会有更多的数据。
In order to get visual representations of the vast amounts of data, like a movie, it’s standard practice to pre-render specific sequences. But what about creating a visual representation of the data in real-time, as if you were there, an observer at an arbitrary point in space and time? This is what astrophysicist Yves Revaz of LASTRO set out to do with the VIRUP, with the help of LASTRO software engineer Florian Cabot, and it meant rendering terabytes of data at 90 frames per second. The latter constraint is imposed by the virtual reality environment, for a fully immersive and smooth experience.
为了像电影那样获得大量数据的视觉表现，标准的做法是预渲染特定序列。但是如何实时创建数据的可视化表示呢？就像你身处其中，从空间和时间的任意点观测它们一样。这就是 LASTRO 的天体物理学家 Yves Revaz 在 LASTRO 软件工程师 Florian Cabot 的帮助下开始使用 VIRUP 做的事情，这意味着以每秒 90 帧的速度渲染TB级别的数据。海量的数据是虚拟现实环境的硬性要求，以期获得完全身临其境的流畅体验。
“Visualization of astrophysical data is much more accessible than showing graphs and figures, it helps to develop intuition of complex phenomena,” explains Revaz. “VIRUP is precisely a way of making all of our astrophysical data accessible to everyone, and this will become even more important as we build bigger telescopes like the Square Kilometer Array that will generate tremendous amounts of data.”
“天体物理数据的可视化比展示图表更容易获得，它有助于培养对复杂现象的直觉，”Revaz 解释道。 “VIRUP 正是一种让所有人都能接触所有天体物理数据的方式。随着我们建造更大的、产生巨量数据的望远镜（如平方千米阵列SKA），这种方式将变得更加重要。”
Astrophysical, cosmological data and simulations
天体物理学、宇宙学数据和模拟
For the moment, VIRUP can already visualize data from over 8 databases bundled together. The Sloan Digital Sky Survey consists of over 50 million galaxies and 300 million objects in general. The Gaia data of the Milky Way Galaxy consists of 1.5 billion light sources. The Planck mission involves a satellite which measures the universe’s first light after the Big Bang called the cosmic microwave background radiation. There’s also the Open Exoplanet Catalog which aggregates various sources of exoplanet data. Other databases include a repertoire of over 3000 satellites orbiting the Earth, as well as various skins and textures to render the objects.
目前，VIRUP 已经可以将集合起来的、超过 8 个数据库的数据进行可视化。斯隆数字巡天(SDSS)的数据包含了超过 5000 万个星系和 3 亿个天体。观测银河系的盖亚(GAIA)数据由 15 亿个光源组成。普朗克任务(Planck)使用一颗卫星，来测量大爆炸(Big Bang)后宇宙的第一道光，即宇宙微波背景辐射(CMB)。以及开放系外行星表，它集合了各种来源的系外行星数据。还有环绕地球运行的 3000 多颗卫星的数据库，以及用于渲染物体的各种皮肤和纹理。
VIRUP also renders data sets of contemporary and scientifically robust simulations based on research. You can watch the Milky Way Galaxy and its future collision with the Andromeda galaxy, our galactic neighbor also known as M31. You can also see huge portions of the cosmic web – the filamentary large-scale structures that extend across the universe – coming into existence over billions of years, based on simulations from a data set called IllustrisTNG which consists of 30 billion simulated particles. A major challenge is ensuring smooth transition from one database to the next.
VIRUP 还能渲染研究中的当代的，科学上稳定的模拟。你可以观看银河系，和未来它与仙女座星系的碰撞，仙女座星系也被称为 M31。您还可以看到宇宙网(cosmic web)的很大一部分——它是已存在数十亿年的，延展于整个宇宙的丝状(filament)大型结构——名为 IllustrisTNG 的数据集的模拟告诉我们。该数据集由 300 亿个模拟粒子组成。VIRUP的一个主要挑战是确保从一个数据库平稳过渡到另一个。
“We considered using existing graphics engines for visualizing the data, but in the end, I developed one specifically for the project. It’s flexible, we can add more data as it becomes available, and it’s tailored to astronomy,” explains Cabot. “For this first release of VIRUP, I have focused on rendering static data, so interacting with the data is still a bit rough and the rendering of simulations can’t yet happen in real-time for example.”
“我们考虑过使用现有的图形引擎来可视化数据，但最后，我专门为这个项目开发了一个。它很灵活，可以添加新发表的数据，而且它是为天文学量身定制的，”Cabot 解释说。 “对于第一版VIRUP，我一直专注于渲染静态数据，因此与数据的交互仍然有点粗糙，例如还不能实时进行渲染这些模拟。”
Of course, it’s only possible to navigate through the data and simulations imported into VIRUP. You can visit the 4500 discovered exoplanets so far, for instance, but the way they look are artist impressions inferred from observation. You can also navigate through the 50 million galaxies measured so far by the Sloan Digital Sky Survey, but the actual data has limited resolution and this limits how much detail can be shown in its virtual representation. That being said, there is still a tremendous amount of data that can be explored with the help of VIRUP. Some of the next steps could be to include databases of objects in our solar system like all of the asteroids, or various other objects in the galaxy like nebulae and pulsars.
当然，你只能浏览导入到 VIRUP 中的数据和模拟。例如，你目前可以参观已发现的 4500 颗系外行星，但它们的外观是基于观测推演的艺术加工。你还可以在斯隆数字巡天项目(SDSS)迄今为止测量的 5000 万个星系中畅游，但实际数据的分辨率有限，这限制了可视化时可以显示的细节量。话虽如此，在 VIRUP 的帮助下你仍然可以探索大量数据。接下来的计划，可能是添加我们太阳系中物体的数据库，比如所有的小行星，或各种其他在银河系中的天体，如星云(nebulae)和脉冲星(pulsars)。
Flexible immersive virtual environment
灵活的沉浸式虚拟环境
For the fully immersive, 3D, 360 experience, you’d need a pair of VR glasses and a computer for running the VIRUP engine, plus storage space for a selection of astrophysical and cosmological data.
要获得完全身临其境的 3D 360 度体验，你需要一副 VR 眼镜和一台运行 VIRUP 引擎的计算机，以及用于存储 TB 级天体物理和宇宙学数据的大量存储空间。
VIRUP is also capable of building a virtual universe in other VR environments, like a dome which is especially useful for venues like planetariums, panaromas, caves and half-caves. The open-software’s transition from the rather personal and isolated experience of VR goggles to the collective, theatrical experience offered by domes and caves, became possible thanks to a collaboration between LASTRO scientists and researchers at EPFL’s Laboratory for Experimental Museology (eM+), and funded by EPFL seed funding for fostering interdisciplinary projects.
VIRUP 还能够在其他 VR 环境中构建虚拟宇宙，例如(天文)圆顶，这对于天文馆、全景天顶、洞穴和半洞穴自动虚拟环境都特别有用。这个开源软件将使用VR 眼镜这种相当个人和孤立的体验，转变为圆顶和洞穴自动虚拟环境可提供的集体的、剧院式体验这件事变为可能，这要归功于 LASTRO 科学家和 EPFL 实验博物馆学实验室 (eM+) 的研究人员之间的合作，以及 EPFL 种子基金资助的用于培养跨学科项目的基金。
“It’s about data discovery. The immersive system means that you can embody the data which has a profound effect on how you actually perceive the data,” says artist Sarah Kenderdine who leads eM+.
“这是对数据的探索。身临其境的系统意味着你可以将数据具象化，这会对你实际感知数据的方式产生深远影响，”领导eM+ 的艺术家 Sarah Kenderdine说。
A journey though the universe – a short movie
With the release of VIRUP comes a short movie entitled “Archaeology of Light”, just one possible journey through the virtual universe made possible thanks to the open software.
The 20 minute movie starts from Earth, and charts out a voyage throughout the various scales of the universe, from our solar system, to the Milky Way, all the way to the cosmic web and the relic light of the Big Bang.
If you’re impatient to see the movie, you can watch in 2D, in 360° and in VR180 on YouTube. If you have access to a VR environment, you can immerse yourself in “Archaeology of Light”.
For the dome experience, the movie will be showcased at EPFL’s next exhibit, Cosmos Archaeology: Explorations in Space and Time, which opens on 21 April 2022 at EPFL Pavilions. A preliminary version of the movie was shown at the Synra Dome of the Science Museum of Tokyo in September, thanks to support from the Swiss Embassy in Tokyo. VIRUP will be presented this month at an exhibit, in Dubai, as part of EPFL’s Virtual Space Tour.