What is Latency? Why is Starlink's Latency Lower than Other Satellite Internet Services?

Okay, let's talk about latency and why Starlink is significantly faster than traditional satellite internet in this regard.

What is Latency?

Imagine you're on a phone call with a friend who is very far away. You say "Hello" into the phone, and then you have to wait a moment before you hear them respond, "I hear you." The time you spend waiting in between is latency.

In the world of networks, latency means the same thing: it's the total round-trip time it takes for your device (like a computer or phone) to send a data packet (e.g., clicking a link) and receive a "response" from a distant server.

This time is usually measured in milliseconds (ms).

• Low Latency: Like talking to someone right next to you, the response is very quick. Web pages load instantly, online games are smooth, and video calls have no noticeable lag.
• High Latency: Like talking to an astronaut on the moon, you say something and have to wait several seconds for a reply. This manifests as web pages endlessly spinning, game characters teleporting, and video call audio and video being out of sync.

Therefore, the lower the latency, the better your internet experience.

Why is Traditional Satellite Internet Latency So High?

This is mainly because traditional satellites are placed too high.

Traditional satellite internet services (like HughesNet or Viasat) use Geosynchronous Earth Orbit (GEO) satellites. These satellites are located at an altitude of approximately 36,000 kilometers above the equator.

Your internet signal has to travel a long journey:

1. Your home dish (antenna) sends the signal up to the satellite 36,000 kilometers away.
2. The satellite then relays the signal to a ground network center.
3. After receiving it, the network center sends the data you requested back along the same path: ground center -> satellite -> your home dish.

Even though the speed of light is fast, the distance is simply too great! This round trip of over 140,000 kilometers typically results in latency exceeding 600 milliseconds. This latency might be acceptable for browsing news, but for online gaming, stock trading, or video conferencing, which require quick responses, it's a disaster.

(Image illustration: Traditional satellites are far, signal travels a long round trip)

How Does Starlink Achieve Low Latency?

Elon Musk's Starlink is clever because it uses a completely different approach: placing satellites very, very close.

Starlink uses a constellation of Low Earth Orbit (LEO) satellites. There are thousands of these satellites, forming a mesh-like network covering the globe, but they are only at an altitude of about 550 kilometers.

Now let's look at the signal's journey again:

1. Your Starlink dish sends the signal up to a satellite 550 kilometers away.
2. The satellite directly (or by relaying through other satellites) transmits the signal to a ground station, and then the data returns along the same path.

36,000 kilometers vs. 550 kilometers — this distance is reduced by over 98%!

The path the signal needs to travel is greatly shortened, and latency naturally decreases. This is like switching from international express mail to same-city flash delivery.

As a result, Starlink's latency can be as low as 20-40 milliseconds, which is comparable to many terrestrial fiber optic broadband connections. This performance is sufficient for almost all internet activities, including the most demanding online competitive games.

(Image illustration: Starlink satellites are close, signal travels a short round trip)

In Summary

Simply put, the core factor determining the latency of satellite internet is the altitude of the satellites.

• Traditional Satellites: Fly high (36,000 km), signals travel far, so latency is high.
• Starlink: Flies low (550 km), signals travel short distances, so latency is low.

By deploying a "space-based internet" composed of a massive number of low-orbit satellites, Starlink fundamentally solves the problem of excessively high latency in traditional satellite internet, allowing people in remote areas to enjoy an internet experience comparable to fiber optics.