What are Stars in Urbit, and what is their function?

As per the introductory article on what Urbit is, we learned that the basic architecture of the network is composed of planets, stars and galaxies, and stars and galaxies facilitate discovery and communication between two entities (such as two planets).

urbit stars illustration
Stars are part of a galaxy

In short, the main functions of stars are peer discovery/routing and distribution of OTAs. Let’s better understand what this means.

Peer Discovery/routing concerns communication between two entities. In practice, it allows one planet to quickly find and communicate with another within the network.

OTAs is an acronym for “Over the Air updates“. In the context of Urbit, they are a mechanism for updating the stars’ software remotely. When a new version of Urbit software is released, it can be distributed to the startups using OTAs. This allows the stars to be updated without having to physically access each star to update the software manually.

This functionality is important because the Urbit system is designed to run on specialized hardware, which means that the software and hardware are closely integrated.

OTAs work through a content distribution network that allows updates to be sent efficiently and reliably to all the stars. When a new update is made available, stars can choose to download and install it automatically, or wait for user confirmation.

In addition to updating Urbit software, OTAs can also be used to push critical security updates and fix security holes, which helps ensure that the Urbit network remains secure and up-to-date, giving users the best possible experience.

To ensure a star performs its role properly, it needs to be online all the time. When a star is providing services to a planet, it is said to be sponsoring the planet. A planet can choose which star will be its sponsor.

Since stars are typically hosted with more robust infrastructure than individual planets, it makes sense that they would be tasked with more computationally intensive tasks like significant bandwidth or disk space.

Reputation and Moderation

As a sponsor, you share a certain level of accountability for the planets you endorse. Should a sponsored planet engage in abusive behavior, others may request that you intervene by issuing a warning or even withdrawing your sponsorship.

While this is an infrequent occurrence, removing sponsorship unilaterally should be seen as a last resort. Currently, this relies on a system of social norms and expectations, but the development of various reputation frameworks can be anticipated in the future. Your reputation as a star holds significant weight, as no one desires to be associated with disreputable entities like unsolicited email providers, which could discourage others from conducting business with you.

The relationship between a sponsor and a sponsored planet involves mutual responsibility and consent. All interactions are voluntary, and if you gain a reputation for supporting abusive planets, others have the choice to disregard you or the ships under your sponsorship. Over time, formal reputation systems may become an influential factor in these decisions.

Additional Services

There are some additional services that stars can provide to planets for the sake of practicality and convenience. Although not mandatory, a star’s privileged position can make these services common.

Some examples of additional services that stars can offer include: providing hosting, operating a Bitcoin full node, and operating a layer 2 rollup to interact with Ethereum.

A star can decide whether or not to charge for each particular service.

Advantages of owning a star in the Urbit network

Each star can spawn 65,535 planets. That is, since the total amount of planets in the Urbit is scarce (about 4 billion in all), each planet has value. A holder of one star can sell thousands of planets.

Stars are much scarcer than planets. There are only 65000 stars in all.

Besides being able to sell planets, the owner of a star eventually in the future can charge a small fee for peer discovery services, OTAs and other services, depending on how the network matures.

Cautions when buying an Urbit Star

Care should be taken when buying a star to make sure how many planets have already been spawned by that star. It is possible that the owner has already sold all of them. We will teach you how and where to buy a star safely in other articles here on the site.

See also: